general-chat

[dusk flax]

I would check the docs. I know the methods are different for the BNO085

[limpid sedge]

ok thansk so much!

it seems to be working now!!!

[dusk flax]

Great!

Hope you can figure out the save, so you don't need to keep calibrating

[limpid sedge]

yea i will try

[limpid sedge]

it appears very gimicky though

the heading only works in one orientation or its opposite, it doesnt work in other ones

[dusk flax]

What do you mean?

Like only when it's flat, or upside down?

[limpid sedge]

if i make a full circle, the numbers only change by 30

flat, if i spin it around, only changes by 30

[dusk flax]

Okay, something is definitely off.

I think based on the accelerometer data, it's not returning x,y,z

[limpid sedge]

heres the funny thing though

using the adafruit script, both headings are accurate now

[dusk flax]

But are they accurate if you spin in a circle?

[limpid sedge]

yep

those ones are made off quants, not magnometers

but sometimes even those are spotty

[dusk flax]

So that uses all three modes, and can calculate for what way it's oriented

[limpid sedge]

each one of the x y z combinations only works in a specific quadrent

the adafruit script is the only one that goes in a circle 0-360, but it is off by ~12-30

[dusk flax]

So if everything is working correctly, if you turn it sideways you don't use x and y because they are being pulled differently. The trig formulas use gyro, mag and acc for true 360 understanding

Did you apply the offset to the Adafruit one?

[limpid sedge]

nope, applying it makes it worse

[limpid sedge]

is this for the adafruit one?

[dusk flax]

Which Adafruit one are you using?

[limpid sedge]

https://github.com/adafruit/Adafruit_CircuitPython_BNO08x/blob/main/examples/bno08x_find_heading.py

both the headings from this are relatively close

i havent added the calibartion to the adafruit one, thats my next step

[dusk flax]

So quaternion is calculated on chip and uses all 3 sensors.

[limpid sedge]

does that mean its more accurate?

[dusk flax]

Generally yes. More data means more accuracy. For example if the board is tilted, it can handle that

[gloomy aurora]

Y

[tame coral]

pi@ROS:~/Desktop $ python pl.py
Traceback (most recent call last):
  File "/home/pi/Desktop/pl.py", line 5, in <module>
    kit = ServoKit(channels=16)
          ^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/.local/lib/python3.11/site-packages/adafruit_servokit.py", line 92, in __init__
    self._pca.frequency = frequency
    ^^^^^^^^^^^^^^^^^^^
  File "/home/pi/.local/lib/python3.11/site-packages/adafruit_pca9685.py", line 176, in frequency
    old_mode = self.mode1_reg  # Mode 1
               ^^^^^^^^^^^^^^
  File "/home/pi/.local/lib/python3.11/site-packages/adafruit_register/i2c_struct.py", line 81, in __get__
    i2c.write_then_readinto(buf, buf, out_end=1, in_start=1)
  File "/home/pi/.local/lib/python3.11/site-packages/adafruit_bus_device/i2c_device.py", line 140, in write_then_readinto
    self.i2c.writeto_then_readfrom(
  File "/home/pi/.local/lib/python3.11/site-packages/busio.py", line 224, in writeto_then_readfrom
    return self._i2c.writeto_then_readfrom(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/.local/lib/python3.11/site-packages/adafruit_blinka/microcontroller/generic_linux/i2c.py", line 98, in writeto_then_readfrom
    readin = self._i2c_bus.read_i2c_block_data(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/.local/lib/python3.11/site-packages/Adafruit_PureIO/smbus.py", line 264, in read_i2c_block_data
    ioctl(self._device.fileno(), I2C_RDWR, request)
BlockingIOError: [Errno 11] Resource temporarily unavailable

I get this error

[tardy badger]

Happy new year to Europe!

USA coming around in less than 5 hrs

Well, eastern seaboard anyway

Can’t forget Canada as well

[rapid geode]

canada had its new year in november

🙂

[tardy badger]

Nonsense

Canada celebrates eternal winter

[tame coral]

Iim gonna Post it in #help-with-circuitpython

[rapid geode]

yeah, except i was picking fresh rosemary this morning. Winter forgot to come. jon snow is a liar.

😛

[rapid geode]

new years fancy pizza mmm

rosemary in the crust, white truffle sauce. 5 different cheeses

[tardy badger]

Nice

Looks yummy

[rapid geode]

was good. i made 2.

i dont think i would buy a tiny $20 bottle of pizza sauce myself, but it is quite nice

sauce was a gift

[tardy badger]

isn't all sauce?

[fierce prawn]

You can buy it for Thanksgiving just for all the praise

[honest jolt]

Happy new year to EST!

[ebon dew]

https://tenor.com/view/new-year-2022-gif-24334949

[hallow locust]

Happy New Years Everyone, hope 2023 was good for you guys, see you in 2024 🎉 🙏

(Im on Pacific Standard Time, so its 10:55 for me)

[devout snow]

Happy new year

[devout snow]

Yeh, im on UTC +1

[hasty quarry]

Happy new year to my favorite nerds

Thanks to this community for truly changing the world

[hallow locust]

same!

[tranquil swallow]

c++ on vscode is giving me a headache

[modern osprey]

Hi all, just wanted to take a minute to wish you a happy new year, most of all good health! These days people don't spend much time or thought on some personal words to their friends and family, they just copy and paste some random message and send it on. So after all we've been though together this year I want to thank you for your friendship and wish you a happy and fulfilling 2018 - you’re the best gymnastics group anyone could ask for. Best wishes, Helen xxx

[honest moth]

https://www.deviantart.com/smashtoons/art/Are-You-Doing-Your-Patriotic-Duty-Today-519828053

[dapper hatch]

Happy new year all. 🙂

[hasty quarry]

Agreed

[urban arrow]

Hey all in case any of you are dealing with a Metro ESP32-S2 with a TFT resistive touch shield on top (prod 1651), here's the working pinouts for the shield (took me some fun and games finding out how to translate these from D6/D7 etc. on a "normal" Metro...):
Shield:
tft_cs = board.IO15
tft_dc = board.IO14
and SD Card:
SD_CS = board.IO9

[violet parcel]

I'm a bit confused with RLC circuits, time constants, first-order/second-order, RC circuits etc when using a microcontroller board. Am I supposed to analyze my own circuits each starting from a gpio or am I supposed to analyze the whole thing including my custom sub-circuits on gpios ?

[tardy badger]

The GPIO pin itself will have some character resistance/capacitance/inductance but you should just be able to use the resistance of the pin as a resistor between gpio and ground. From there you can do your analysis

Depending on the data sheet, you may actually get the average capacitance of the pin as well

I would be surprised if most modern data sheets didn’t include some Thevenin value to represent the pin’s influence on the circuit

[violet parcel]

Hopefully the data sheets have that. Especially that most microcontroller companies dont publish their internal MCU schematics. I was trying to understand the theory but couldn't help thinking - ok but I'm using microcontrollers boards, wont that affect things... - and that was preventing learning

[tardy badger]

Which MCU are you thinking of using?

Samdx1 data sheets have simulation characteristics tables that they provide

Which would be helpful

[violet parcel]

I have a couple, grand central express m4, teensy 4.1, stemma qt esp32s, uno r1 to r3 and a mega 2560 r1

Normally I'd say that it's hard to not use both a mega 2560 (because it can easily handle old 5v components) and a 3.3v stemma qt esp32 that can easily buck-down 5V from a battery pack to 3.3V to prototype stuff. Dont like to wear down the more expensive MCUs for no reason

Anyway since it might matter this is really an X=>Y question. The X problem I'm trying to fix is that I have no idea what I am doing building a circuit and Im trying to become better at circuit design and having a clue by building a circuit theorically before I buy anything so that I will know what I need and having a couple of circuit to use as building blocks in my brain

Because whenever I build something the problem is not that I dont know how to use the components individually. It is that I don't know how to use them together and be reduced to trial and error instead of having a clue of what I am doing and why

[late fulcrum]

There are several ways to get this sort of knowledge. If you prefer a more discovery based approach, you can get a solderless breadboard and an assortment of components and build things to see how they work. For a more directed/explanatory approach, there are a variety of electronics learning kits available (Elenco, Snap Circuits, Brick 'R' Knowledge, etc.) with step by step instructions and explanations of how the components are used and how the circuits work.

[violet parcel]

I was hoping books might help but from what I am reading on many websites this is an experience things and all a book will do is tell you the theory of why they works

but unless a book is specifically on say RF it wont mention building blocks like frequency filters. I mean not even practical electronic for inventors goes deep enough for me. It talks of relays and pros and cons of each type but not what to do to actually solve these problems

Another suggestion Ive seen is to grab a circuit simulator with a lot of examples circuit since it will include many circuits that are commonly used as building blocks to not reinvent the wheel

A corollary of this is how do you learn that a PLL, frequency synthetizer and frequency generator and op amps go together if no one ever told you. That is not a simple google search

[late fulcrum]

There are some good books out there. I don't normally recommend starting with RF, which has complexities of its own, but getting the basics of passive components (resistors, capacitors, etc.), discrete semiconductors (diodes and transistors), and then integrated circuits (both digital like gates, analog like op-amps, and mixed like timers).

For a thorough approach that involves some effort but rewards it with solid understanding, "Learning the Art of Electronics" is an interesting book. It's basically the course notes for a hands-on course for learning electronics. You can obtain the parts and go through the labs to learn things from the ground up.

But you can get a much quicker and cheaper start with something like the "100 in 1" kits, Snap Circuits, etc.

This kit is inexpensive and supports some RF projects as well https://shop.elenco.com/consumers/electronic-playground.html

There are a bunch of useful learning kits on that site

[shadow siren]

You could invest in

There is also a parts kit to go along with the book you can get

[late fulcrum]

That looks like a good middle-of-the-road option, between the basic learning kits, and the "whole ball of wax" approach of Learning the Art of Electronics

[shadow siren]

There is even a section on microcontroller programming in the end section of the book.

[violet parcel]

I feel like these are for total beginners no ? Like I said " The problem is not that I dont know how to use the components individually." it is that I don't know how to use them together. Like I know how to use my sensors individually, I2C, SPI, chaining them together, a led, a passive speaker etc. I just don't know how to use more than 1 together and I can't do real-world circuits because of that. Like if I use a led and a passive speaker of the same gpio I have no idea what's happening to the voltage and current at the 2nd component. I could ask every time but I could also know the theory. Same with level shifter I just know they are required but I dont know why.

Another example is a demo circuit about an lm386. But why these farads capacity, why these resistors capacities etc. Yes that can be found I guess with datasheet but that I wont help if I add something else to the circuit and now I have to to figure out what values to change these to

[shadow siren]

The book goes through ohm's law and basic electronic theory and why you have the various components and why they are used.

[late fulcrum]

It seems like you have basic knowledge of components (which is a great start), but not detailed knowledge of how they work together. Hooking an LED and a speaker to the same GPIO isn't likely to do something useful without some additional circuitry, for example.

If you wire two components in parallel, they'll see the same voltage. If you wire two components in series, they'll see the same current. These are the basic sort of principles you need to understand what happens when you hook stuff together.

[violet parcel]

yeah in this case it would be to alarm the user about something detected from a sensor on another gpio

which I can do

but if one of them isn't 5V on a 5V MCU I am completely stuck

Like I know that I would need a buck-up or buck-down but I wouldn't how to connect it. And this is one of billion problems I could encounter. And it stops me everytime because I have no clue

So I would like to get that clue so when I see something of a different voltage for example I dont panic

or have the reflex that if more power source is noisy I already know to make a filter for it with caps with the correct circuit in mind so that I again dont panic. These are examples I know but Im sure there are thousand that I dont know

And the next step would be able to understand something like this in a datasheet to know if I need that IC or not: - because currently I barely understand 1% of it -

[late fulcrum]

This sounds like you're looking for broader, deeper, more detailed working knowledge of how to put stuff together, how to choose approaches, and how to debug things

[violet parcel]

I wish I could explain better but I have been stuck on this set of problem for a while that is basically summarized in "having a clue and stop costly trial and error" for months and I just cant get throught it

[violet parcel]

yeah that sounds like it a lot

Just like when I program in C++ I have regular trees, character trees, red and lack trees etc in the back of my mind and depending on what I want to do I can pick which one I need for my app. Like for search completion a character/word trees seems the best approach

[late fulcrum]

When you're developing new things, trial and error is a part of the process. You learn how to limit the damage so it's less costly, but I've been at this a long time (over half a century) and I still burn stuff.

[violet parcel]

but in electronics I cant do that at all

[late fulcrum]

A lot of it to me is like programming, I try to modularize and refactor, and eventually get a feel for where I can divide a circuit and develop a piece at a time and then put them together with some confidence they'll actually interoperate

[violet parcel]

The only thing Im kinda able to do is put the correct amp in something using a resistor

and use parallel resistiors if I dont have the exact correct one. So if I have a single IC or another component I can generally feed it what it need in it's spec

[late fulcrum]

When I'm building stuff, it still starts like this

[violet parcel]

I guess I should start with the very basic circuits, but it's hard to know what a rf bypass filter actually does without seeing what it does visually or hearing it...

[late fulcrum]

I got a huge advantage there because I learned on a system called Lectron that let me get a real intuitive feel for what components actually do.

I still remember the first time I truly grasped what a capacitor does, using Lectron

I had read a ton of books saying stuff like "a capacitor conducts AC but blocks DC" which is true as far as it goes, but not a concept I could really internalize.

[violet parcel]

yeah thats my problem when I read art of electronics

I read something like this and have no idea where it comes from

practical electronics for inventors is a bit better for such explanation but doesn't go deep

[late fulcrum]

So I took a small capacitor, and charged it to 9V with a battery. Then I pulled it out and held it in my hand. "Okay", I thought, "I have a capacitor in my hand, and it's holding 9V of charge. Now what?" Then I went the next step and connected the capacitor to a switch and an earphone. When I pressed the switch, I could hear a "click" in the earphone, which was the sound of the flow of electricity out of the capacitor.

[violet parcel]

like "here is detailed explanation of how to convert ac to dc and why we use capacitor to do it" but we have to take into account these problems but Im not going to tell you how to solve them

so I kinda understand that ac is sinusiodal and a type of capacitor cut it in halves to just keep the dc. But I still dont know how to build one or have a deep knowledge of it

[late fulcrum]

The other problem (and it's an especially pernicious one in a complex field like electronics) is that different people learn and understand differently. You need to find a book/kit/whatever that lets you understand the concepts in your own way.

[violet parcel]

Like for me it's still not clear how the capacitor know what voltage to hold when used with a battery like when the voltage keep going down

[late fulcrum]

Note: capacitors don't convert AC to DC by themselves, the most common approach uses a capacitor and a diode or diodes

[violet parcel]

Like Im not sure if it will take the voltage after every time it is emptied or it only take the original one as long as the circuit is on (but then why would I need a regulator)

ie: over time as my circuit is kept on and the battery voltage goes down Im not sure if the cap will go 5.0V - empty - 4.9V - empty - and so on keeping that voltage during a time constant but not over the time the circuit is powered on or it will go 5V - empty - battery goes 4.9V - cap still 5V etc

[late fulcrum]

That's where the diode comes in. As long as the voltage on the anode is higher than the voltage on the cathode, the diode will conduct. So when the incoming sine wave becomes higher than the voltage on the capacitor, the diode conducts and the capacitor charges.

The capacitor will only go up to the battery voltage, and then go down depending on how fast energy is being drawn out of it.

With a sinusoidal input, the process is a little more complex as the incoming voltage keeps varying back and forth

[violet parcel]

yeah but the explanation didnt cover what happens if the DC part is too fast to empty the charge. As far as I know if the cap get emptied it lose the voltage it had in it

Like what Im trying to say is that if I have a battery that goes down in voltage and my cap empty faster than it charges it wont keep the circuit under the starting voltage of the battery

[late fulcrum]

You're mashing together several concepts at once, leading to confusion

[violet parcel]

hmm I thought they were the same. if I use a cap to produce DC 120V from AC 120V before step-down I thought the goal was to keep things always at 120V

so when it goes down to 0 V and to -120V Im releasing charge to keep it to 120V

[late fulcrum]

I'm unclear on what you mean by "if the DC part is too fast"

[violet parcel]

but if it goes up from -120V to 120V Im accumulating charges. But like how does it know it's 120V when it lose all charges ? I mean like I must have a time limit to do this

[late fulcrum]

And "the capacitor gets emptied" is the same as "it loses the voltage it had in it"

Again, you can't use a capacitor alone to produce 120VDC from 120VAC.

[violet parcel]

Ok let me try to clarify

None of the book Ive seen tell me how the capacitor knows what voltage of charge it must keep since the voltage written on it is the max possible.

It seems to be that is set on the first charge that enters it

but what if it gets emptied of all charge

[late fulcrum]

The voltage on a capacitor depends on the amount of charge in it. You start with the simple DC case. If you hook a capacitor to a 9V battery, a large current will flow briefly from the battery into the capacitor, charging it to 9V. And yes, you want to do this with a capacitor rated for at least 9V.

[violet parcel]

Ok. So now what if the capacitor is too low capacity and lose all charges and the capacity being used a bit the battery has dropped to 8.9V

the capacitor is holding 8.9V charges now or still 9V ?

[late fulcrum]

Whether it has a high or low capacitance, it's still basically a bucket. If you fill it, and then remove some charge, the voltage will go down.

[violet parcel]

ah I understand my confusion now. I tried to understand a capacitor from a specific application of capacitors

Now I get it's just like a battery except faster

but if I use it voltage goes down too

[late fulcrum]

Right. A battery's voltage will vary some with the charge level, but a capacitor's voltage is entirely determined by the charge level.

[violet parcel]

thanks for you patience I get it a lot more now 🙂

I'll try to be careful next time to not assume that a specific application explains the whole thing

[late fulcrum]

Yeah, it's tempting to imagine the components somehow "know" what the voltage should be, but they're simple devices following fixed rules. Their behavior comes directly from these rules.

[violet parcel]

Yeah btw for the 120AC thing I know my explanation sucked but just didn't want to confuse myself even more. I know there are limits like since you are only using the positive part of the AC sinusoidal wave that mean at most you get half the voltage of the source so 60V DC and you have to use a rectifier etc

[late fulcrum]

Even a half-wave rectifier will give full voltage. It works out to more than full voltage, since 120VAC RMS has a peak that's 1.4 times the RMS voltage, so a capacitor connected to 120VAC via a diode will charge to on the order of 170VDC

[violet parcel]

so hmm might as well asks the next question

if my capacitor get a voltage spike of says 12V instead of the 5V the circuit uses and is high capacity enough I know it will absorb it and still provide 5V to the circuit

put at the price of higher current

so if there is a led after the capacitor the led might get toast, unless I put another resistor but then my led would get dimmer than normal when I dont have a voltage spike

[late fulcrum]

You're glossing over some circuit functionality that's important here. If you really applied a 12V spike at zero impedance to a capacitor, it would instantly charge the capacitor to 12V. However, there's not going to really be zero impedance, so the capacitor will start charging towards 12V at a rate determined by the source impedance and the capacitance. If it's a brief spike, the capacitor generally won't charge far, so it could be some fractionally higher voltage than it started with. Using the bucket analogy again, it's as if you turned on a hose briefly, which would slightly raise the level of the water in the bucket.

I'm not sure what you mean by "at the price of higher current": the capacitor will tend to load down the supply voltage more if the voltage changes suddenly, and a higher current will flow into the capacitor then, maybe that's what you mean.

[violet parcel]

" higher current will flow into the capacitor then, maybe that's what you mean." yeah that is what I mean but doesn't that increased current flows in the rest of the circuit too ?

[late fulcrum]

Now to the LED. Suppose the capacitor briefly charged to a higher voltage, which would tend to push a higher current through the LED. That won't toast it instantly unless the voltage changes a lot (or you have minimal headroom between the supply voltage and the LED voltage, leading to a small current limiting resistor that can't limit the current effectively)

No, the rest of the circuit will tend to draw current based on the voltage of the capacitor. So the voltage into the capacitor will briefly be higher, but the voltage out of the capacitor will have a smaller bump, proportional to the change of the capacitor voltage.

Unless your circuitry is non-linear (like LEDs), in which case, yes, the current change due to the voltage change can be more than proportional.

[violet parcel]

yeah that is what I thought, higher current in cap = higher voltage, not a problem for a led because of voltage drop but higher voltage also mean P = RI has gone up

so my current limiting resistor might not be enough anymore

[late fulcrum]

There are many ways to avoid the voltage getting out of hand and damaging your circuit. One popular approach is a voltage clamping circuit (and optionally a current limiting circuit) ahead of the capacitor, so the 12V incoming spike is redirected elsewhere, and only a lesser voltage spike reaches the capacitor.

[violet parcel]

But if I multiply it by says 10x in normal uses Ill have a dimmer led. Unless I use a current-limiting component but then if I do that I'll need to dissipate heat and so on... or a shunt/fuse

[late fulcrum]

I normally run my LEDs conservatively, so a 10% bump in capacitor voltage won't overload them.

So you'd have an LED that's 10% dimmer (actually less than that loss because LEDs are more efficient at lower currents)

But if you want to run LEDs at max current, you probably want a voltage regulator circuit instead of just a simple capacitor.

[violet parcel]

capacitor scares me hence this discussion 😄

I feel like if I don't use the charges fast enough and a 120V cap on a 5V circuit Im going to end up with smoke

or if I use a 12V cap the cap will explode instead

[late fulcrum]

A 120V capacitor can withstand up to 120V. If you supply 5V to it, it will only get charged to 5V.

However, if you're using something like a capacitive dropper to produce a 5V supply from a 120VAC source, there will be multiple opportunities for things to go wrong.

[violet parcel]

no I just thought that it was like a battery as well in the sense that more charges = higher voltage and it can exceed the input voltage

[late fulcrum]

I often use 100V capacitors in 5V circuits, it's fine as long as they aren't electrolytic

[violet parcel]

like I thought that's how peoples ends up with a 100KV tesla coil or a 170VDC from 120VAC like you mentionned earlier, charge it faster than its discharge time constant

[late fulcrum]

The voltage is proportional to the charge, but the only way for a capacitor to produce a voltage that's higher than it's supply voltage is if you change the capacitance of the capacitor while it's charged (not a common use case!)

You can raise voltage with inductors, or use voltage multipliers (generally arrangements of capacitors and diodes that arrange for the supply voltage to charge several capacitors that end up in series, producing a higher voltage, those only work on an AC input)

[violet parcel]

Inductors can be nice to watch : . "You cut my circuit so im sending the current in ur switch"

[late fulcrum]

Yup. That energy has to go somewhere!

[violet parcel]

yeah that is why I must have a complete understanding of it before I use inductors or capacitors 😄

and trial and error isn't acceptable with something that can spark or do an accidental RF spark-gap

[late fulcrum]

You're getting closer to a working knowledge of capacitors, inductors are ... more complicated.

[glad ruin]

I wouldn't call them "more complicated", but they are arguably less intuitive.

[ebon dew]

So Pretty

[violet parcel]

so for the capacitors am I right to assume that since it is sorta a battery that if I want to use something with a voltage drop without the voltage drop I could use one to provide charge of the correct voltage when the circuit is being voltage dropped ? Like if I put a led right after a battery but dont want the rest of the circuit to now have battery V - led voltage drop = X V remaining. Like I could put a cap in front of the led and have it switched out of the circuit in regular intervals so it stays up for a couple of ms because of the cap and is reconnected so it wont affect the rest of the circuit when it's on

I had a bit of fun yesterday with the caps olympics

Like which one make the led last the longest after power is turned off

[late fulcrum]

Ignoring capacitors, you're basically asking how to power a circuit with two elements (the LED and something else) with the same voltage. As I mentioned above, things wired in parallel will see the same voltage. So the voltage source (whether it's a capacitor or not) would be connected to the resistor powering the LED, and also to the other circuitry to be powered. Then both circuits (resistor + led circuit, and the other circuit) will see the same voltage.

You can also play games with pulsed power to distribute things across time as you describe, but I consider that a separate issue.

[tardy badger]

Re: Applications of KVL/KCL

🤓

[violet parcel]

yeah I just dont know if gpios are parallel or series ... so it might not matter

ie: it's not that I dont understand it it's just that normally I use a microcontroller and mnost of them dont have schemetics so 99% of the circuit I use is hidden from me

So everyone I read "so in an RC circuit" or " in a series circuit".... ok but but I dont know if the microcontroller circuit is that and how adding stuff on an gpio do anything for that

if gpios are parellel like I think they are I can just use another gpio for the led

[tardy badger]

Well, a portion of the gpio can be represented as a resistor in parallel, there would also be a capacitor in parallel as well due to some inherent parasitic capacitance

[late fulcrum]

You can regard a GPIO as a (weak) voltage source.

[violet parcel]

btw the IR leds won the caps olympics because I have no idea if they turned off when they turned off 😄

[tardy badger]

If driven as an output, if it’s an input, probably just a RC circuit in parallel no?

You probably could just do some small femtofarad capacitor, resistance could be negligibly small

[late fulcrum]

I scribbled out a couple of diagrams. In this case, I'm using "V" to represent a voltage source (which could be a GPIO) and "C" to represent some circuitry to be operated along with the LED. In diagram A, the circuitry will see the voltage from V, regardless of the forward voltage of the LED. In diagram B, the circuitry will just see the forward voltage of the LED.

[violet parcel]

I was hoping to see the response time of the higher capacity caps because my caps olympics idea sounds stupid , obviously higher capacity = led last longer

but I couldn't see the response time even if I blinked the led 55 times so I would see when it missed one

[late fulcrum]

A larger capacitor will take longer to charge as well as longer to discharge (unless you assume it's being charged with infinite current)

[tardy badger]

If you want to measure voltage across, you could measure it with an ADC

[violet parcel]

so it was originally about both response time and capacity, but in fact I couldnt see with my eye any difference in response time when I hit the button to turn off the led

[tardy badger]

Since that would measure in parallel to your LED

[violet parcel]

I'll keep that in mind when I need a led to show the battery are working where C is the MCU

especially on MCU that have no indicator they are working and appear dead otherwise like the picos...

I still dont understand everything about caps but I was able to make some logical connections yesterday and I slept less stupid than the day before so that is good 🙂

[violet parcel]

Ok Ill go build one ! 😆

More seriously thought I cant wait to have some sort of 3 prongs voltage source as a permanent circuit so I can solve the conversion to 3.3V/5V once for all

[late fulcrum]

It's a journey, we all have to assemble understanding a chunk at a time

[violet parcel]

normally I dont ask these questions on fictional stuff or components I cant buy but...

yesterday I saw supraconductivity means r = 0 ohms

but a short circuit also means that so Im very confused

like my circuit would blow up if I used superconductive wires ?!

[late fulcrum]

Superconductivity does exist, but it's not something that would show up at random. In general, you can usually get way with pretending that things are ideal. Like assuming wires have zero resistance. In real life, they have very low resistance. So when you make a short circuit across a power supply, you don't really get infinite current (even if you did it with a superconductor) because the power supply can't provide unlimited current in the first place.

But suppose you had a working circuit, and replaced the wires with superconductors. It would still work, just with slightly higher efficiency. Instead of a bulb getting 2.999V due to wire resistance, it might receive 3.000 volts. Not really worth worrying about in most circumstances.

[violet parcel]

but a sperconductor would have no resistance right or even then it's ideal and the correct wording is that it would have limit resistance -> 0 but never exactly 0

[late fulcrum]

That's the surreal thing: a superconductor does indeed have a resistance of exactly zero. You can induce a current into a superconducting loop and it will flow forever.

It's a weird effect that comes out of some physics that doesn't seem intuitive, as "ideal" behavior is generally not seen. But in this case, it is.

[violet parcel]

ok but that wont that immediately cause a short circuit and cause the battery to overheat etc ? Some forums said that it's not defined by ohm law so resistance = 0 ohms for a superconductor doesnt mean the same as resistance = 0 ohms for a short circuit

[late fulcrum]

If you were to connect a superconductor across the battery terminals, a large current would flow and the battery would possibly heat up and be damaged. However, connecting a piece of wire across a battery would have the same effect.

Normally a "short circuit" doesn't specifically refer to zero ohms as much as a "short cut" where the current (often an excessive current) flows through an unintended path.

[violet parcel]

I once connected a spring across the 2 prongs of a night light and put it in the socket and the socket charred, the spring exploded (stainless steel afaik) and a fuse blew out in the breaker room when I was very young. Still dont understand why since it's like adding a wire to it and the spring should have resisted the heat... But I guess it was some sort of short circuit

But besides that with the complexity/hidden box of microcontrollers it's kinda difficult for me to say something is a short circuit

Maybe for learning fundamentals I should just not use an MCU

[late fulcrum]

Yes, the spring probably provided a small resistance, but think about it. Suppose the spring had a resistance of 1 ohm. 120VAC (if that was the mains voltage there) would attempt to push 120 amperes through the spring, producing over 14,000 watts of heat. Obviously it's not going to survive this for long, and the excessive current would also trip the breaker.

When you hook a GPIO directly to some voltage, set it as an output, and try to switch it to another voltage, there will be a tug-of-war with the GPIO pulling one way and the voltage source pulling the other. In most cases, the GPIO will lose, sometimes sustaining damage in the process.

[violet parcel]

but it's connected to a load (the night light) so Id thought the load would limit the current being put in it

That is why I still dont understand it because I didnt put a string by itself in the socket. It connected it throught the hole in the prongs of a night light which should have limited the current to what the night light need

but I guess the current never actually reached it because the path being the prongs is the best for the current

[late fulcrum]

It is a short circuit, the voltage is offered two paths, either up one prong, through the night light, and out the other prong (the usual mode of operation), but you added a second path, up one prong, across the spring, and out the other prong. This was a (much) lower resistance path, so it drew (a lot) more current.

If you had managed to plug one prong into the socket, touched the other prong to one end of the spring, and the other end into the socket (DO NOT ATTEMPT THIS), the night light would have limited the current as you would have had a series circuit instead of a parallel circuit.

[tardy badger]

I think it would be easier to think of short circuits as a “least effort circuit,” at least that’s how my brain thinks of it

The term short circuit does feel weird sometimes

[violet parcel]

I see. And yeah for readers dont attempt this. Just trying to understand stuff I did as a toddler that unfortunately we all tried to do and that's why child protection exists for sockets

[late fulcrum]

That's why I pointed out I think of it as a "short cut circuit"

[tardy badger]

Yeah

My brain omitted the “cut” from your term lol..

[violet parcel]

So last question in this topic

Because I feel like that toddler from back then that didnt know any better about it

My multimeter claims to be 240V max. And on videos I see I can stick the projngs into a socket to measure its voltage

but I cant work the courage to do this. On videos it seems to not be a big deal they dont even use leather gloves with the prongs

[tardy badger]

Yes, there’s a 10A fuse

Slow blow, so you can hold it in long enough to measure the current

[late fulcrum]

I prefer a CAT IV rated meter and probes if I'm going to be connecting it to mains.

The 10A fuse is for measuring current, not voltage

[tardy badger]

Sorry, multitasking lol

[violet parcel]

so it seems that I am right to approach it as if we talk about mains Im not doing anything even if I had all the knowledge in the world unless I have a fluke or something high-end like that and certified leather gloves for electricity

[late fulcrum]

Annoying, my cat chewed through my fancy expensive CAT III leads (while I prefer CAT IV, I'll use a CAT III meter if I have to)

[violet parcel]

my multimeter says it's cat IV and has prongs lik your pic ()except straight) but at the price it costs me I dont trust it and even if they showed a cert Id assume it's fake

Had an electrician come here to install something and they used my multimeter to stick it into a socket and test what they installed when they saw it but amateur me wouldnt do it lol

[tardy badger]

I have no idea what mine is, just that I can measure 600V/200mA fused, 500V max to ground

It is a $10 craftsman multimeter

[violet parcel]

yeah but these are just claims just like computer PSU says they are 750W but the parts inside are rated at 400W max on cheap psus

[late fulcrum]

Woo hoo! My fourth patent was granted on December 26 and I just found out!

[violet parcel]

thats why I say I dont trust my multimeter since it costs me 49$ and is true rms. That just dont respect financial laws so you cant have cat iv at this price or resistance to 240V or so despite what they claim

[late fulcrum]

I get a lot of use out of my $5 Harbor Fright multimeter. However, I don't use that one for mains voltage work. But to see if I'm getting voltage out of a GPIO pin, it's fine.

[tardy badger]

Apparently my multimeter sells on eBay for $60 used

[late fulcrum]

I'm pretty sure CAT IV requires at least 600V so if it says CAT IV and 240V, that seems bogus to me.

[tardy badger]

$191 new on Amazon, $129 new on eBay

[late fulcrum]

I'd trust the eBay "new" one before I'd trust the amazon one.

[tardy badger]

All I remember is I paid like $10 for it back when Kmart had those games you could win points on and use the points to redeem for things

I got a decent tool box with that too

Oh there it says CAT II

Derp, should have took the leads off

[late fulcrum]

I wonder who really made it. You could look up the actual manufacturer from the Craftsman part number back in the Sears days, unsure if the Kmart ones work like that too.

[violet parcel]

" measures up to 600V AC/DC voltage, 10A AC/DC current and 60 MOhms resistance, electrical tester also tests temperature, capacitance, frequency, duty-cycle, wire on-off, and test diodes and continuity.
easy operation - Switch the dial to the function you need, and the LED lights on the jacks will shine accordingly. To plug in the leads is easy. Autoranging saves you the hassle of having to know which range of value. Large 2.9 LCD backlight display, easy-to-read digits offer a 6000-count resolution.
MULTI-FUNCTION - Non-contact voltage testing and Live function with sound and light alarm. Flashlight on the back ensures easy use in dimly lit places. Min/Max/Average to record signal fluctuations. Stable kickstand, Pen slot on the back, Low battery prompt, Data retention, Auto power-off.
SAFETY FIRST - IEC Rated CAT III 1000V, CAT IV 600V, CE, RoHS certified. Anti-Burn with double ceramic fuse and thermistor protection circuit. High Voltage Protection is active on all ranges. Double insulated unit. Silicone protective case prevents it from falling damage."

It's a kaiweets. Bought it back then because of reddit wiki recommendation on /r/electronics or something like that

but I believe none of it anyway not at this price

[late fulcrum]

That sounds like a nice meter on paper, at least

[tardy badger]

I got it through sears since Kmart and sears were kind of the same brand at the time I got it

[late fulcrum]

Do you have the model number? Should be something like 3 digits, a period, and some more digits

The 3 leading digits are a code for the manufacturer

[tardy badger]

It’s a Craftsman 034-821410000

[violet parcel]

yeah it's good enough for electronics and simple to use because of colored probes and led flashing in succession to tell me how to connect the probes and the auto rms thing (very nice for resistors)

[tardy badger]

Sells for $25 on Walmart marketplace

[violet parcel]

I just dont like that it scream like a smoke alarm and a led turns red when testing continuity scares me everytime and the manual doesnt says why

• the number on the screen keeps going up when it does that like a reverse countdown before something bad happens

same thing happens if I touch the two probes to each other and keep it on continuity testing

[patent hemlock]

i have a totally useless software patent that, as far as I know, was basically a waste of money (company's) and time (mine)

[tardy badger]

Toaster pop up detection software?

🤓

That’s actually a useful patent

[late fulcrum]

Most of mine is of dubious usefulness, but there is a clever bit of reading off resistor ratios with an MCU and no additional hardware.

[tardy badger]

Oh neat

[patent hemlock]

"Software business platform with networked, association-based business entity access management "

[tardy badger]

Salesforce?

Wait, physical access management or virtual?

[violet parcel]

I dont have a patent but I was in a coding competition once to analyze made-up surface radar contacts over a large amount of water to prioritize them and after I made the code I jokingly asked if I should patent it and they says they would classify my patent. That day I found out you can ask for a patent but they can prevent it from being patented, you get no protection and can't tell anyone about it 😦

[patent hemlock]

it was basically a "network" model imposed on business relations for the automotive industry -- auto dealers have very complicated relationships

[tardy badger]

Those relationships are written into law in many states

Not necessarily the actual relationships, but how they’re managed

[late fulcrum]

That happened to Richard Feynman during the war. They asked him if he could think of patentable ideas based on atomic energy and would give him a dollar for each idea. He just spit out "submarine, airplane, boat". They said the submarine and boat were taken, but the airplane idea was his. They thanked him, but he insisted on getting his actual dollar. Then he forgot about it until years later when someone called him to ask about atomic planes. He wanted to know why they had called him in particular and they said "your name is on the patent!"

[patent hemlock]

each dealership has a 🫏 load of units and they each have their own connections, even with each other

yeah, i found out about mine 10 years after it was granted

[tardy badger]

I tried to file for a patent back 10+ years

It was for a system to stop vehicles using a system that detected vehicles going too fast approaching red lights or 4 way intersections

And also stopping them

[violet parcel]

I got an offer after the code competition so I guess I didnt do too badly but I dont know if it was related to that since Im not interested to go throught the process of getting a clearance just for 9/5 "work". I feel like it's a huge intrusion on my life just like overtime

[tardy badger]

Using large electromagnetic arrays

Basically there would be sensors leading up to the place of concern, actively detecting and reacting to people’s speed

[violet parcel]

stopping them with like a magnet ?

[tardy badger]

Yup

Keep in mind I was like 17 at the time and had very crude understanding of electromagnetics

[violet parcel]

if the magnet can stop a car can't it screw up their biology too or pacemakers etc ?

[tardy badger]

Sure

[violet parcel]

Like the warnings on big neodymium magnets ?

[tardy badger]

Don’t speed

Lol

[violet parcel]

Yeah but when I read it I thought this was more for involuntary speeding

[tardy badger]

My brother jokingly proposed just having large barriers pop up

💀

[violet parcel]

Like someone is in coma because of a medical issue and nobody can stop their car

[tardy badger]

Anyway, there was an additional component that would be installed on the vehicles of habitual speeders which would disable the car and take control to bring the car to a stop.

The idea was to stop drunk drivers and reckless drivers

[violet parcel]

I wish something like this existing to stop speeding pilot (ie: plane crashes) like a tractor beams or for careless submarine operators

[tardy badger]

I think my idea is a lot more feasible with current technology

Just disable user input to prevent their actions from influencing the stopping of the vehicle

Sort of like FSD on Tesla but only for stopping accidents at intersections which claim thousands of lives every year

[violet parcel]

Yeah I know I'm just being dreamy / semi-serious. / wishing ..

[tardy badger]

Not sure how you’d do it on airplanes and subs/boats

[violet parcel]

Would be even better if you dont signal a turn it stops your vehicle so you dont run over a pedestrian who had no way on knowing you would turn on them or crash with another car

[tardy badger]

Or just prevent cars from moving when peds are in the cross walk

[violet parcel]

Well for submarine it would be from a much bigger ship I guess and a magnetic field under the ship slowly causing the submarine to magnetically gets close to it

The weight difference would cause the magnetic field to affect the ship less (like a submarine tender/cargo ship) vs the much more lightweight submarine

Tehnically I guess the same could be done from a bigger airplane that is dispatched to stop a crash

[violet parcel]

That's only fair if you the same to peds trying to cross on a red light when the cross walk signal isnt on with magnets under their shoes!

[violet parcel]

you got anything on FCC site yet ?

I think the order of precedence is like patent < FCC < USB cert < HDMI cert

[late fulcrum]

No, nothing on the FCC site

Other than my ham radio license

[dusty citrus]

hey guys... i am about to buy an acer RTX 4090 + intel core i9 laptop... but i hate windows 11.. so i will try to install windows 10 on it... now i am really concerned because...

My current laptop has windows 10... multiple components are corrupted, including (microsoft store, drivers, windows features + sandbox and many more)
after i downloaded a windows 10 ISO from the offical website and registered it with the key, the components are still corrupted and the brightness slider disappeared from windows display options.
reinstalling drivers always returned that it could not find them and manually selecting also didnt work.
If i am right then after reinstalling windows, EVERYTHING gets erased... right? so why is it still corrupted?
i am not using pirated software/activators and i dont even know how that works.

any comments on that?

[patent hemlock]

install linux? 😀

[dusty citrus]

i dont know how that works

and i dont think im smart enoguh for that

@patent hemlock

[patent hemlock]

please don't do that

[dusty citrus]

do what?

[patent hemlock]

"at" me in a big, bold font -- if i don't reply, it's because i don't have an answer for you

[devout snow]

pinging him

[dusty citrus]

bruh

this server aint helpful at all

why am i here

[patent hemlock]

and i ain't your bruh

[dusty citrus]

yes you are

[devout snow]

Thats not nice

[dusty citrus]

dude... why you sent me here?

[devout snow]

Maybe you get help tomorrow

[dusty citrus]

/:

[devout snow]

can you wait one day?

[dusty citrus]

my messsage will be buried

already

[devout snow]

Nah

Just wait okay?

[ebon dew]

Laptops usually have a manufacturer OEM version of Windows and not a retail version. There might be some settings that don't work correctly if you use a retail version even if it's a generic OEM version. A default install assumes that it's for a desktop but there are laptop features included with that you can tweak such as power options, display options, etc...

If your laptop has special features like a brightness slider or knob something like that would need the manufacturer version. Recommend you try to contact tech support from the laptop manufacturer. Though many of us here have PC support knowledge this discord isn't a good replacement for your manufacturer tech support.

[violet parcel]

or even a good replacement for pc problems specific discords

[ebon dew]

Here's a discord specifically for free PC Tech Support https://discord.com/invite/r-techsupport-749314018837135390

[rapid geode]

fun fact. mercedes first public demo of a self stopping car at an intersection plowed right through and crashed 😛

[violet parcel]

I hope first contact isn't a self stopping spaceship that plow into the planet

[rapid geode]

ha

thats what we did to the moon, sooo

[violet parcel]

I'm sure they have something like murphy law and dunning-kruger elsewhere in the universe too 🤣

[rapid geode]

we are just a little rock in the way of an interstellar highway.

[violet parcel]

yeah nobody stopping here with the binary star system next door

It's like being a castle near versailles "your little fort is okay I guess but versailles is next door"

[patent hemlock]

https://www.space.com/37015-schiaparelli-mars-lander-crash-investigation-complete.html

[late fulcrum]

Heh, just read a novel like that ("Gate Crashers", by Patrick S. Tomlinson)

[tranquil swallow]

where does FCC have all those pictures of electronics internals, i cant find it

[late fulcrum]

Generally under the report for a specific device (for example https://fcc.report/FCC-ID/QEA-U282-2G4R)

[ebon dew]

I used FCC docs once to figure out why a specific router continually overheated and ports would die. It was because they didn't put heatsinks on the PHY chips that were all stacked so close together causing an overheating situation that reached up to 135F, well beyond what they claimed it would reach. Modified it with some little heatsinks and an active cooler, voila no more overheating, no more randomly dead ports. Those docs can be very helpful.

[late fulcrum]

I used the link I posted to get the schematics for an R/C car so I could modify it

[ebon dew]

that sounds fun

[rapid geode]

Soo, would something like a mac book motherboard have schematics in there? Or do they get away with not having to do that? (bla bla right to repair bla).

[late fulcrum]

Many things do not have schematics, it seems to be optional. I've seen some where the schematic links are marked "private" as well. That said, Macbook schematics are findable.

[ebon dew]

If it's wireless it has to go through FCC certification, in the US at least.

[late fulcrum]

Yes, but "certified" and "making schematics publically available on the FCC site" are two different things.

[ebon dew]

Yup and some of the documentation can be vague sometimes or with poor quality images or schematics. The quality of documentation varies.

[late fulcrum]

The R/C car was a $10 find at a thrift store. The FCC ID yielded the schematics, and while it supports its own proprietary battery, it also supports generic DeWalt style 20V tool batteries. A prime platform for experimentation.

[ebon dew]

wow, you just plug a dewalt battery in that thing? it's got a slot for it. i've never seen that. that's really cool.

[late fulcrum]

I honestly did not expect that, but yup, you slide a little plastic piece over (it's even marked) and plug in a dewalt battery. Thanks to whatever thoughtful person added that little feature.

[ebon dew]

That is such a great idea. Aren't most RC cars like 7.4V or 14v? Would it need special motors for 18/20V or would it use a buck converter?

[late fulcrum]

This one's set up for 20V for whatever reason (it says "20 VOLT" in big letters on the side). But it's not fast, it kind of creeps along.

[ebon dew]

Here's the one I have. It's 7.4V. Removed the top and 3D printed a place for a cheap FPV camera.

[late fulcrum]

Ah, nice mod.

I'm making another one into a Ghostbusters style "remote trap vehicle" with a 3D printed trap.

[ebon dew]

Hmm there are rock crawler modes that will sacrifice speed for torque. Might be able to change it with a receiver mode switch.

awww that's so cool

[late fulcrum]

I'm building a matching retro style transmitter and adding a few additional control channels for "open trap", "lights", "sound", etc.

[ebon dew]

and a custom transmitter... of course you would. I can't do something like that, beyond my skill. That is so cool.

[late fulcrum]

Here's a pic of the original movie prop I'm trying to replicate

[ebon dew]

oh wow that is actually really really close

[late fulcrum]

I'm using an off-the-shelf transmitter module that takes serial data

[ebon dew]

sbus?

I still haven't quite figured out sbus :/

I'm using a lot of Radiolink stuff. I think Flysky is more popular but Radiolink was a cheap entry point.

[late fulcrum]

I ended up with Lemon RC. https://www.buddyrc.com/products/dsmp-diy-module-for-legacy-transmitters-dsmx-dsm2-compatible

I designed the housing in Fusion's "sheet metal" module and had an outfit laser cut it for me

[ebon dew]

Oh it's got an STM chip. That moment when you're like "hey I know that chip".

[late fulcrum]

Yeah, some of them have an ATmega8 and some have the STM chip. I also found an STM chip in a computerized COVID test module.

[ebon dew]

you never cease to amaze me. why not get a transmitter and gut it instead?

I guess it would still need to replicate the prop anyway?

[late fulcrum]

I have grand plans to open source the whole thing, and the 1970s era Futuba transmitter it's based on is hard to find

[ebon dew]

Someday I would like to make an RC car work with RFM modules and circuit python. Problem is the tx/rx speed of rfm modules have too much delay. Was thinking maybe if I put like 4-6 rfm modules in sequence and enumerate through them it might work. still beyond my skill level but a neat idea.

[late fulcrum]

I played with a few different approaches, hitting the same sorts of problems. The LemonRX modules are design to support the old PPM protocol, which they internally convert to and from the serial data stream. The current lashup drives the transmitter with PPM (provided by PJRC's PulsePosition library) and taps off the serial data from the receiver and decodes it (LemonRX doesn't document the protocol, but it's the same as the Spektrum protocol but at a slightly different baud rate)

[ebon dew]

I've noticed that most of the protocols for RC are all fairly similar but also different enough where if you don't have a oscope to discect the protocol you're basically locked into their ecosystem.

[late fulcrum]

I figured I could use one of the "satellite" receivers intended for diversity reception to save cost (since they're just the receiver bit without the demodulator) but curiously, the more complex receivers are cheaper.

Once I determined it was asynchronous serial, I just needed the scope to figure out the bit times. Then I was able to figure out what the bits meant from the Spektrum documentation.

[ebon dew]

I suppose that is the hurdle with RFM/LORA. It can send or receive but not both simultaneously. I think if you can put enough of them on a board (maybe 20 of them) it might be possible to do both fast enough. The board would be bigger than could fit in a small RC car. Maybe stacks of boards like a cubesat. Easier said than done. Too many hurdles vs. an RC receiver for like $6.

and working with RC itself has it's own hurdles like the voltage differences between all the different components is frustrating to deal with.

[late fulcrum]

Note that the ones I'm using are mostly one-way, there's a fast channel for controlling things, and an optional slower backchannel for sending back telemetry.

However, they are 2.4GHz spread spectrum, small, and inexpensive.

[violet parcel]

My understanding is that they always asks (99.9%) of the time to restrict it. So it's "there" but can't be seen by the public. It seems since 2002 that those classification never expires which is a bit unfair to me so it seems most schematics are from before 2002 which I guess is great if you time travel and need to make an obsolete device from the last millenia. Also it didn't give the software for the microcontroller which I think most of the important stuff is. . ps: just answering so that readers intersted inn the discussion can get some understand of what that FCC thing is.

[tranquil swallow]

trying to remember this really old computer architecture book i read with a sectiont that covered binary math stuff like two's complement, otherwise any recommendations?

[patent hemlock]

i was trying to find the one i used back in the Dark Ages but memory and search aren't coming up with anything -- i remember several pages devoted to that kind of math (and i love that it still sometimes trips up things)

[rapid geode]

machine code for dummies?

[lusty fossil]

Does anybody know if kits for electric bicycle conversion exist that are higher torque and lower speed? I want to convert a free bicycle I got two electric to travel between sites at work, while potentially towing a trailer with up to 200 lb in it. I am speed Limited except for in one area where I need to cross the street but even then I don't think I would want to go that fast, so I'm really looking for something that's high power but not necessarily High speed. Anyone have thoughts?

[hasty quarry]

Crimping dupont by hand is among the most tedious things I've ever done

My crimps just don't align properly and when they look like they did, they don't fit into duponts

Infuriating, just horrible

[rapid geode]

So, for clarity, you are not conforming to e bike laws in this case? (not a judgement, just a question for spec)

the motor i have has an internal planetary gear system

so its 250w, but only 25kph with a lot more torque

if you really need torque you want a central motor that uses the bike gears, but that almost always needs a purpose made bike (and they cost a lot)

[dusty citrus]

@ebon dew !!!

why am i banned i just asked a question about why pc isnt working after i used format c

[lusty fossil]

What would I be breaking?

Going slowly?

[rapid geode]

ebike laws are 500w max power, 32kph max speed in most places in north america.

you can buy WAY more powerful motors, but technically they are illegal on the road.

(but noone cares)

[lusty fossil]

Oh I don't think I'd need that?

[violet parcel]

What the max power and kph until they become illegal for the laws of physics ?

[lusty fossil]

C

[rapid geode]

hehe

[violet parcel]

ie: stalling speed before they become airborne

[rapid geode]

anyhow. yeah if you want to stay within the law, you need something with gears. either interal to the hub motor, or run the motor through the bike drivetrain

[violet parcel]

but what if someone isn`t actually on it ?

Like a drone one ?

[rapid geode]

....

[violet parcel]

afaik you cant have a fine or lose points on driver license if someone else was driving your vehicle

[rapid geode]

also, you need to decide what happens when the battery is dead. hub motors sap energy if you try to pedal them

(pedal only)

[violet parcel]

stuck in place and have to wait for towing (possibly from a tug electrical bike with a better engine so they can tow multiple bikes on a mass casualty site along with someone on them)

[rapid geode]

....

are you ok?

:P:

[violet parcel]

yeah just being silly. Not sure mass casualty was the right word here not english speakers

but I meant like many peoples being out of electricity in says a park

more seriously it's kinda unfair since some peoples can go faster than that on regular bicycles

I wanted one for a long time but everytime I think of it: 1) probably could make one for less than 5000$ for a lawmower motor. I dont see what else add to the insane cost 2) I worry about lazyness because it's a bit like going to the gym and having an automatic hydrolic system do reps for you

[rapid geode]

a lot of the e bike laws dont realyl make any sense

but its better than nothing right now

[violet parcel]

3. and this is still a serious one. Some cities in canada have road that are so cratered that Id need an e-motocross - like montreal

[rapid geode]

ha

thats called a mountian bike

but no idea what montreal would need that for. its pretty flat and paved there

[violet parcel]

yeah mountain bike wont do for ostrich or pterodactyl road nests in montreal

like a couple of months one ate a fire truck

[rapid geode]

aaaanyhow. i need to make some money this week with my CNC. what can i make for $0 and sell for $500?

hmmm

😛

O_o

ostriches ate a fire truck?

ha

[violet parcel]

yeah that one

imagine your e-bike encounter that at 35kph

[rapid geode]

that happened in front of my house. they did sewer work, but didnt backfill corectly and it all fell in

but no cars got stuck

anyone want a $100 billet aluminium feather case? 😛

no? ok

oooh, i have something to sell i already made a few years ago. i put them in a box when i moved and forgot about them.

some wood guitar bridges

should have at least 20 of them

[violet parcel]

item from us: 100$ canada custom fees: 0-800$ (randomly determined, seeded with time and customs officer mood) taxes: 15% of the total of the two previous amount shipping carrier fee: 80$ for doing nothiung. End cost: up to 1100$ for a 100$ item

[rapid geode]

ha

no

first, im in canada alreayd

soo

but tax is 13%. brokerage fee is $20 max by law.

[violet parcel]

I add a single cable on adafruit and already have to pay 59 US$ for delivery...

[rapid geode]

buy at digikey. adafruit uses UPS which is a real problem

[violet parcel]

yeah I have seen several posts here before, on the forums and reddit about how some especially DHL charges much more than that and hope you dont know it's 20$ and you have to wait hours to fight it

[rapid geode]

digikey is slightly more money, but $8 or free shipping

[violet parcel]

the customs cost depends on where the item was made too, not where it was shipped from

so if they decide adafruit mostly resold an ali express item you get the full percentage on electronics

[rapid geode]

theres almost never real duties on anything.

but like i said, use digikey

then you dont need to deal with any of that

[violet parcel]

yeah my issue is that they are unable to tell me how much in advance even with a ATIP request

[rapid geode]

they stock almost everythign on the adafruit site

[violet parcel]

yeah the problem is in the "almost" and having to assemblr a 100$ order to get free shipping

that has cancelled a lot of my projects before

[rapid geode]

pay the $8 then

stop being a baby

😛

[violet parcel]

didnt know it was that little I expected them shipping from the US

It's not that. I dont like when I dont know how much I'll spend total for an item in advance

[rapid geode]

digikey and mouser are both $8

[violet parcel]

Doing an ATIP request on a description of eleectronics and the service itself not being to tell me is a huge red flag

That is clearly because they decide randomly

[rapid geode]

anyhow

digikey ships next day, no customs, no worries.

[violet parcel]

yeah basically I'm assembling my next order atm in google sheets for when I dont need a wheelchair anymore

it interferes a lot with my life so I cant really do circuits at the moment but I use the time to learn more about electronics theory

So far I have an SI frequency generator, couple of bucks, buck/boost etc a PLL and an lm386 with the 5V speakers from adafruit. Reading practical electronics for inventors atm with their suggested electronics purchases so I can get a vaerity of caps/transistors/basic ic2 etc since I noticed I dont have many different types and would be stuck for certain projects

[violet parcel]

Feel like there are less and less regulars here not normal that i am the last speaker for a day or two in a few channels...

[patent hemlock]

some people have lives beyond discord 😏

[rapid geode]

yes, some of us also go on reddit

wait, what?

bah. im trying to draw a kid guitar that fits on my cnc in one go. the neck is always too long though. hmm

[violet parcel]

Im just saying a few years ago this discord had much more peoples

[rapid geode]

its new years. everyone in on holiday

relax guy

[violet parcel]

and much more chatting. Seems like chip shortages pushed a lot of peoples away. Seeing the same at the makerspaces for electronics too

[rapid geode]

well, nothing is the same now as it was in the before time. cant expect that

[late fulcrum]

There's also an ebb and flow dependent on season, weather, school, work, and other factors.

[rapid geode]

its 520mm long, and my machine is 305.

yup

thats not gonna work

haha

[late fulcrum]

Haven't you heard of folding guitar necks?

[rapid geode]

ha

i think i need to make some trades with my friend.

[spice moss]

github skylines is here for 2023

[fading hare]

too bad I did absolutely zero interesting things in 2023 on GitHub 😦

Oh, wait, it's not as bad as I thought... https://skyline.github.com/tbjers/2023

[spice moss]

my year got like end of the year focused so much

[tardy badger]

Mill it in two steps?

[tardy badger]

I don’t do much except on random days where I hyper focus lol

https://skyline.github.com/skerr92/2023

most of my years are not amazing. 2020 I think was my best year

[rapid geode]

yeah, but its a bit tricky cause when you flip it to do the back carve, there is not where to really clamp it.

[tardy badger]

too bad you don't have one of those super cool vacuum beds that help supplement that issue.

[rapid geode]

i have a super cool vacuum bed

hehe

but theres not enough surface area to work well

there would be avou 6-7 square inches on the last op. which is 60-70 lbs of pull force

with pins to hold it laterally

its not bad but i dont think it will hold well enough

[night crescent]

WE ARE LIVE! SHOW AND TELL! https://youtu.be/-uoTEYZq-6s

[tardy badger]

Zip ties? Lol

Also

I love gig fiber

Down loads go brrrr

[rapid geode]

ha

im lucky to get 10mb/s

they damaged my fibre a while back and never bother to fix it

[tardy badger]

🥲

[thin relic]

Does anyone know where I can ask for recommendations for a project? 🙂

[tardy badger]

You can browse the Adafruit learn site

2500 learn guides, among that is cool projects

[night crescent]

WE ARE LIVE! ASK AN ENGINEER! https://youtu.be/mkWPgJ-WvWc

[lucid linden]

This is my first message in Discord, let’s see if it works….

[fossil dawn]

Worked 👍

[astral cedar]

Hi

[devout snow]

Yeah, you must be a pro

You got it first try

[patent hemlock]

https://developers.slashdot.org/story/24/01/04/0126247/niklaus-wirth-inventor-of-pascal-dies-at-89?utm_source=feedly1.0mainlinkanon&utm_medium=feed

[patent hemlock]

That led him to quip, "In Europe I'm called by name, but in the US I'm called by value." ```

[hasty quarry]

What is the significance of a root-mean-square over just a mean?

[tardy badger]

From a statistical standpoint, it tends to represent a closer or more true value than just the mean

[tardy badger]

Probably good to emphasize this is in relation to normal distributions

[whole jacinth]

for stuff like sinusoidal AC signals, it’s a more accurate description of the delivered power (because polarity reverses, but power flow doesn’t, at least for resistive loads)

[tardy badger]

Yeah, very true

[rapid geode]

i like my power trapeziodal

[tardy badger]

I derive my power from natural sources, my home has tree phase power 😂🫣

[rapid geode]

newfie power

(newfounlanders say tree for three)

(usually with an f word before and after)

😛

[dusk flax]

Does anyone have a home WiFi mesh system they like? I purchased a new one from Netgear and they over charged me ~$400 and so am retuning it and looking for a new brand

[tardy badger]

AmpliFi is pretty decent imo

I’ve used it, it was pretty decent

I operated it in Ethernet backbone mode

The AmpliFi Instant is what I used, though personally currently I have a UniFi Dream Machine Pro and two APs

[spice moss]

i have asus AI mesh

[tardy badger]

Is a dream machine pro overkill for home internet? Yeah probably

[weary fiber]

I'm trying to make a glove control system for cosplay electronics, and I'm a lil stuck on how I wanna design this

My general structure is like

A helmet with the complex electronics, and some sort of button controls on/near the hand

[tardy badger]

I’d use a touch controller, ideally something that can work over I2C

[weary fiber]

I wanna avoid running wires (so I could maybe do a tiny lipo/MCUin the glove) but how would they communicate? I'm assuming a low-profile RF module but idk

I'm willing to spend a lil for the right solution-- going for polish/useability here

[tardy badger]

You could use a small coin cell, touch controller, and then like an esp32-s3 qtpy

Or a small LiPo, the LiPo bff, esp32 QtPy and a touch controller. Use conductive thread for the contact in the fingertips or something

[weary fiber]

Ooh yeah coin cell's better-- I'm mainly confused about the communication method. I know esp32s have wifi/bt, so... would one create a tiny wifi access point? would I somehow pair them over bluetooth?

[tardy badger]

You can probably put the glove one in AP mode, have the main one connect to it when you have say a switch in a specific position or something like that

If you’re using Arduino, that should be pretty manageable

Idk if circuitpython supports AP mode quite yet for ESP32

[weary fiber]

Oh I'm using the arduino ide and doing everything in c++

starting to realize the limits of the arduino IDE, but setting up VSCode with makefile commands & such is too much work

[honest jolt]

PlatformIO?

[weary fiber]

Honestly I just need to get off my butt and learn how to configure that lol

[patent hemlock]

if it's too much work, you can always just use a text editor (zero setup) 😀

[weary fiber]

dang, it's looking like wifi/BT between microcontrollers is the way to go

I was hoping I could just like... buy some sort of RF breakout board that would essentially allow transparent UART between the boards-- somethin cheaper and easier than BLE/WIFI enabled boards

[patent hemlock]

that is pretty much the definition of "wireless"

[dusk flax]

Which one?

[patent hemlock]

the closest i've come to "painless" cross-communication is mqtt over wifi

[spice moss]

RT-AX55 the one router i have the older is still as node

[weary fiber]

Okay yeah, distilling down this issue: if I've got two physically-separate wearable microcontrollers, is bluetooth/wifi the best way for them to communicate (assuming minimal throughput)?

[spice moss]

the asus AIMesh microsite https://www.asus.com/microsite/aimesh/en/index.html

[patent hemlock]

depends on the micro-controllers and how much "work" you want -- you can get all sorts of combos with wifi, BT/BLE, or other radio-enabled controllers, but the effort to program them will all be different and they all have different capabilities

and you have to factor in power requirements, as well

[weary fiber]

at least for the glove bit, I think I have my winning combo

tiny MCU with BLE, tiny battery manager, and I can just use a few GPIO for wearable buttons (I think)

[patent hemlock]

the stemma/qt port also adds a lot of extension capabilities beyond just the GPIO, including GPIO extenders -- have fun!

[timid anvil]

Where can I ask for help with my xbox one?

[rapid geode]

www.microsoft.com

[timid anvil]

Funny ha ha

[timid anvil]

Nvm figured it out

[rapid geode]

🙂

[dusty citrus]

Hello people I just installed Windows 10 Pro and I do not have the brightness slider in the window settings

Any help is appreciated

Windows already says that I have the newest display drivers

[tardy badger]

First decent snow storm of the season

[dusk flax]

I miss the snow. Where abouts are you?

[honest jolt]

Apparently we are supposed to get a decent amount of snow this weekend (Massachusetts)

[ebon dew]

That's beautiful.

[tardy badger]

Utah, wasatch front

[dusk flax]

You're in the south east of the US right? If you see that it's time to move...

[dusk flax]

Never been to northern Utah. Was in the south part last year

[hasty quarry]

Hey guys, if I'm sourcing power to my circuit from a 5V wall outlet supply, should I still be wary of noise with a good capacitor or something?

I don't really know when to worry about this

[spice moss]

lots of snow with cold weather

[late fulcrum]

It depends on the quality of your 5V supply and how much your circuitry cares about noise.

[nocturne agate]

so i deepfried an led

whilst testing an arduino

well, now i know it works

i connected it to 5v and gnd

bad decision

i literally heard it burning inside

[cinder cloud]

yay first mistake successfully accomplished

you have to burn things to learn

[nocturne agate]

i have fried several things

just not an led

[cinder cloud]

there's a first to everything

but have you fried rice?

[nocturne agate]

lmao

i have

[cinder cloud]

shark fried rice

@nocturne agate tried embedded rust?

[nocturne agate]

uhh

i use it for a lot of stuff but not embedded

[cinder cloud]

oh i see

how u find it?

[nocturne agate]

i love it

[cinder cloud]

it's rare to find a programmer that loves his language lol

[nocturne agate]

yes

ive migrated an app from kotlin to rust today

10x faster

and actually works

[cinder cloud]

||i use arch btw||

[nocturne agate]

||same||

[cinder cloud]

Which framework or?

[nocturne agate]

just a cli app

nothing big

[cinder cloud]

ooh i see

that's still cool

[nocturne agate]

actually not really cli either

[cinder cloud]

😭

[nocturne agate]

can you use rust for arduinos

just curious

[cinder cloud]

yes u can

[nocturne agate]

https://blog.logrocket.com/complete-guide-running-rust-arduino/

[cinder cloud]

https://youtu.be/ZPSqhb4KKNc?si=2QEAuGHp1M8pde3d

[nocturne agate]

oh my god

https://tenor.com/view/phineas-and-ferb-phineas-i-know-what-were-going-to-do-today-gif-15622268

[cinder cloud]

HALs are starting to pop up in rust

and maybe check the embedded rust book

[nocturne agate]

i will

[cinder cloud]

goodluck fam

[lyric stratus]

Is there a good channel for fusion360 questions?

[rapid geode]

probably the printing channel? or just here.

speaking of fusion.. boing

also... dont drink milk shakes when you are already cold from being outside.... top tip.

[half plank]

Any way to mirror the red laser and ir light through a set of lenses to be able to fit the max30102 in close constraints.

[rapid geode]

technically yes, but youll need mirrors and lenses/glass that work with those wavelengths. Ordinary glass or plastic may not be adequate.

[half plank]

What would be a good process or can they be bought

This is what I would be using. Periscope lense

[rapid geode]

hmm. (side note, i had a prism from a russian sub)

[half plank]

Red-Reed light. Blue - ir

[rapid geode]

im not an expert, i only know that certain light wavelengths need special mirrors. like lasers

co2 laser is IR range

[half plank]

Ok

[rapid geode]

tv remote is 940nm. a laser cutter is 930-1060.

so maybe look at some co2 laser first surface mirrors and lenses

[whole jacinth]

um, CO2 laser is typically around 10.6 microns, so order of magnitude off. you're going to need toxic materials like ZnSe to deal with CO2 wavelengths

[half plank]

Ok. Thanks for the help

[whole jacinth]

oh, for that device, it looks like the IR LED peaks around 880nm, so visible light optics might work, but somewhat more poorly

[rapid geode]

oh, 10600. eek. thanks. haha

[violet parcel]

You know you won at electronics when you have something like for ur repair shop:

and here I thought an oscilosscope and digital microscope were the biggest expenses

[honest moth]

yo

YOOOOOOOOOOOOOOOOOOOOOOOOOOO_

[cinder cloud]

yoooo indeed

[random saddle]

#help-with-3dprinting may help

[hasty quarry]

This is going so well

[wary veldt]

👋 which channel can i go to for help with issues on the adafruit RGB matrix hat?

the 64x32 matrix display i have it hooked up to works except the bottom half of the screen always puts blue on max/255 when running examples (but turns off appropriately when examples aren't being run).

[ebon dew]

Welp it's covid season I guess. 2nd visit to the ER in 3 days. First hospital didn't know what to do and started handing out morphine like candy.

2nd hospital tested positive for covid and got some antibiotics and steroids.

https://tenor.com/view/covid-19-vaccine-gif-24513727

[late fulcrum]

Note that there are some tweaks you have to do for 64 row displays (additional address line, and different wiring for some versions)

[ebon dew]

It will do that if there isn't a good connection on a pin. The 64x32 matrix panels adafruit uses and the library splits each panel into an upper and lower half.

R1,B1,G1 are one half, R2,B2,G2 is the other half in a 6 RGB pinout.

[patent hemlock]

i hope it all goes well

[wary veldt]

It wound up being something to do with the Pi (it was an older one). After extensive wiring troubleshooting I just switched the Pi 3b+ I was using for another Pi 4, same demo and settings (except changing GPIO slowdown for the 4), and it worked! My guess is probably something with the GPIO on that older Pi is bad. It has been through many projects, so I wouldn't doubt it 😛

[violet parcel]

well that's a bit disapointing. Normally I dont keep the brand in screenshot but that is to illustrate this is an ethanol conversion for car... with basically no vibration/shock/dust/heat protection at all not even comformal on the board and it's like 4$ of electronics sold for 200$. A bit surprised there is no LCD either or that you have to open it to change the percentage of ethanol (bottom-left)

[cinder cloud]

steal the design, improve it, and sell it for cheaper, ruin their market

[violet parcel]

1. Dont have a car 2) Dont have the money to purchase 10 PCB for no reason 3) I have no idea how this works 4) was it really worth it to ping me when I'm just discussing this and clearly not asking to solve a problem here ? 5) they are illegal to make/use in my country Id have to move to the US and I haven't won the green lottery despite participating

[last vector]

i don't think they meant that much by their comment...

i maybe a little late to the party or missed things but given all the drama around art tablets going on at the moment has there ever been a concerted effort to make an open source/open hardware drawing tablet?

[cinder cloud]

people learn by making projects, not learn to make projects

• wasn't serious tho dw

[violet parcel]

what do you mean by "people learn by making projects, not learn to make projects" ? I just enjoy watching teardown videos when I feel bad about spending money on electronics and remind myself I have already saved a lot more money than I have spent avoiding commercial devices that were less capable than simply an inexpensive 3.3V MCU and IC 🙂 Atm I'm working on making the code on an RP2040 to be able to use an old sony remote to remote control the circuit and some "logic blocks" like knowing how dark it is in the room to light the headlights/backlights on

[weary fiber]

I commissioned B/W pixel art of my fursona, then added it to the firmware of my Ender 3 as a bootscreen

I think it came out good :>

[last vector]

love this. love to see furry makers too! :3

[cinder cloud]

but yeah the automobile industry needs some open sourcing (not a 2007 electric tesla)

[dusty citrus]

crack websites be like:

1. Install program;
2. Run patch and wait for the process to finish;
3. Reboot system;
4. Enjoy having a Virus :D

[slim shard]

Try installing Windows someday, at least a virus tries to be subtle about its misdeeds.
🐧

[tardy badger]

I have a ton of pokemon cards I’d love to grade, but grading is expensive. So the logical choice is to purchase the things to start grading cards myself. Hashtag making projects for myself lol

The highest grade for my cards will be a double gold duck

[violet parcel]

need a cam possibly connected to rpi, portable, to take good quality pictures of very small electronic parts/chip lettering since my smart phone camera is broken when I need a pic to make you guys understand what I am trying to do

maybe 64mp arducam ?

[night crescent]

WE ARE LIVE! Desk of Ladyada - Final Revision Push, 600 and beyond https://youtu.be/USnrJEMbDpg

[floral tartan]

Hello, what's the better way to protect the fragile nOOds? I've broken one recently and I can't seem to find a sleeve for them that still keeps them flexible

[raw orchid]

Hi!

I just got a few of these guys

https://www.adafruit.com/product/3178

How can I connect STEMMA QT devices to it?

Which piece do I need to add a connector?

[dusty citrus]

Rate My New Desktop 0 to 100

[ebon dew]

https://www.adafruit.com/product/4209

Red - 3.3VDC Power
Black - Ground
Blue - I2C SDA Data
Yellow - I2C SCL Clock

[tame coral]

how much power does a fully decked out pca9685 draw from its terminal block when 12 servos are moving?

[patent hemlock]

depends on the servos

[tame coral]

i got 12 mg966r

[patent hemlock]

12 x servo max draw would be a good start

so that's about 12* 1.5 == 18A, which is really too much for that board

note that is for the stall current, so if you're not preventing the servos from turning, the actual draw will be less, but dependent upon load

[tame coral]

well yeah but I need 12 servos to move at the same time

[patent hemlock]

two boards, two power supplies

[tame coral]

pain

[patent hemlock]

you can't fight the laws of physics -- well, you can but the result is usually painful

[tame coral]

what, the board will fry if I give it too much amps?

whats the max amount of mg966r I can run at the same time so the board doesnt go kaboom?

[patent hemlock]

according to my search, the board is noted to burn out over 10A, so splitting your 12 across 2 boards is within that limit

(cat on keyboard)

[glad ruin]

I think the bigger question here is what are you doing that requires 12 servos?

Hobby servos are notorious for their inconsistency and tend to have excessive power draw when idle because they are effectively stalled.

And with 12 of them you're going to see just how unreliable and inconsistent they are.

[tame coral]

a robot dog lol

because right now, some servos just dont move at all with my current power

or move to the completely wrong angle

or the wrong servo moves

[patent hemlock]

some of that is indicative of insufficient power, some of that is due to inconsistencies in hobby servos (you may need to have trim adjustments for each one) -- as for the "wrong one" moving, that may be due to overload or a code error, which will be hard to separate until you resolve the power issue

[tame coral]

Do you recommend any power supplys which can supply enough power?

[violet parcel]

Trying to figure out how to connect this "SPI"(?) LCD to an rp2040:

From a schematic with the rp2040 and lcd together on a separate product this is what they did but it doesnt make much sense:

The issue is obviously that their pins dont correspond to anything SPI

and no there are no instructions specific to rp 2040, only for pure arduinos, one stm and numbered raspberry PIs sbc

[fossil dawn]

don't confuse GPIO8 with pin 8 of the Pi pico. GPIO8 is Pin 12 of the Pi pico. And Pin 8 of pi pico is ground so not GPIO

[fossil dawn]

this doesn't make sense to me either tbh

[violet parcel]

there's not even a gpio25...

[fossil dawn]

Except if they're doing something with PIO (programmable IO) of the Pi pico and they aren't using the SPI hardware of the RP2040 at all

[fossil dawn]

lol right

RP2040 does have a GPIO25. Different boards might have it broken out

[violet parcel]

the above diagram for the pico doesnt have a gp25 thought. But here is the diagram for a numbered rasperry pi:

I guess this is the only thing I can really start from but I bet rasperry pi sbc pins can be reconfigured so the actual pins are meaningless

But even then there isn't at least 4 pins like standard spi

miso is missing I think

meh I guess I'll have to try it

guess MOSI = data in (DIN) SCLK = clock (CLK) and CE0 = chip enable/chip select (CS) makes sense(?)

[fossil dawn]

looks like that to me as well

[fossil dawn]

sounds right

The RP2040 names its SPI pins TX and RX because it can be "master" or "slave". So I would do RP2040-SPI-TX -> DIN

[ebon dew]

Not sure where these directions are from but they seem to indicate that GPIO is the physical pin #. So GPIO25 is physical pin 25 which would be GP19. The physical pins are the ones in the grey box.

Just remove the GPIO part and it's basically telling you which physical pin # it is.

[violet parcel]

these are the schematics for the version of the LCD soldered to an rp2040 chip they sell apart

[ebon dew]

GP# is not the same as GPIO#

[violet parcel]

it shows the same LCD connected to an rp2040 on a printed PCB so I thought it could help

[ebon dew]

but even if you follow that schematic it appears as if they're using pins from both SPI busses.

[violet parcel]

yeah. But if they are GP # like penpengu said it makes sense

I guess next time I'll stick to adafruit stuff ...

Instead of that confusing mess

[ebon dew]

I think this is more of what they meant. These do match up to the physical pins.

[violet parcel]

but why two ground, and 2 tx ?

it's an lcd screen rx doesn't make sense either

[ebon dew]

Yes they don't make sense and they're on 2 different busses. Pin 9 & 10 are on SPI bus 0. Pin 11 & 12 are on SPI bus 1. Not sure where you got that diagram but I don't think it's a correct diagram for the Pi Pico.

[violet parcel]

this is the schematic for the rp2040 combo version: https://files.waveshare.com/upload/6/60/RP2040-LCD-1.28-sch.pdf

this is the wiki for the loose version without an MCU that Im trying to figure out how to connect to MCUs other than the 3 shown: https://www.waveshare.com/wiki/1.28inch_LCD_Module

ah yeah I think I see the problem now. They used a rp2040 directly not a pico. Not the same pinouts

so I can only really use the pinouts they show for the raspberry pi 3 or better to figure out how to do it with other MCUs

[ebon dew]

ohhh it has an RP2040 integrated on the back of the display, sorry havent seen that one before.

[fossil dawn]

The grey boxes = Pin numbering of the pi pico PCB
Green boxes with "GP" = GPIO number of RP2040. They're 1:1. So GP10 is GPIO10 and so on

[ebon dew]

I thought you wanted to hook the display up to the Pi Pico. It already has an RP2040 chip on it. Are you trying to do board-to-board communication with uart?

[fossil dawn]

waveshare has 2 products. That round LCD itself. And that round LCD with RP2040 onboard

I think Kitteh has the first one, right?

[violet parcel]

Yeah give me a min to explain

I have the LCD without rp2040. I want to hook it to a pico W. I thought the schematic for the LCD with the rp2040 would help with that

I dont want to use an obsolete MCU like arduinos so Im hoping to find a way (and make a program) to connect/code them on my grand central M4, pico and teensy 4.1 so I can reuse that lcd as much as I can

yeah but the pico dont have a gpio 25 on the pinout

[fossil dawn]

lol right yes. forgot that again

could just be that any GPIO works for that 🤷‍♀️. Seems to be just the backlight

[violet parcel]

I think I'll just work it out from the raspberry pi 3/4 connection diagram

Another fun thing is that's it's round so many coordinates in it's resolution wont even display

Like it's still adressed as a rectangle screen even if round, so for instance (1,1) will not do anything since it's not present in the round

thanks for your time/help @fossil dawn and @ebon dew . Nothing like trying and seeing if it works with the stock image

[bold rose]

hello

[tame coral]

Hello

[bold rose]

hi I'm new here

and I'm having some issues

can I discuss it here or elsewhere?

[hard estuary]

Welcome! You can ask here or you may have better luck with the #help-with channels depending on what you need help with

[bold rose]

I'm having problems with installations. I have a Raspberry Pi Pico and I've installed circuitpython onto it. I've read some documentation about the basics but when I tried to import the board module, it threw an error saying that "No module named 'board'". I have no idea why this is the case as I would assume that the board module would come installed with circuitpython? I've tried importing digitalio and the same error occurs. I'm very new to this and any help would be fantastic. Thank you.

[rapid geode]

i think skerr uses those?

[floral tartan]

Hello, what's the better way to protect the fragile nOOds? I've broken one recently and I can't seem to find a sleeve for them that still keeps them flexible

[half plank]

How can I make 5 i2C max30102 sensors interface separately with an arduino nano

[umbral phoenix]

@half plank Does the sensor breakout allow choosing different I2C addresses? up to 5 addresses? If not, then you can use an I2C multiplexer, like a TCA9548A or PCA9548

[half plank]

No, but that will work. Thanks!

[umbral phoenix]

you could also use more than 1 I2C bus, but I'm not sure if the nano allows that many

[violet parcel]

how do I find a circuitsim that has as most parts as possible ? It seems every of them are either costly and/or tied to a specific manufacturer. Like Ti dont seem to offer their ltspice compatible models anymore due to "legal issues" or their ltspice derivative. Some like hytek and silicon chips make pretty unique stuff etc

I doubt it has any adafruit MCU either

[late fulcrum]

If you're doing analog simulation, you probably don't need logic chips like MCUs. If you're doing logic simulation, it's far simpler.

[violet parcel]

mostly want to know the power requiements in advance and make sure Im providing the right resistors and caps since circuits are getting more complicated and I want to understand what's going on in "building blocks circuits" I mentionned before like rf filters or power management. I guess I can blackbox ICs but I would have liked to have a graphical representation of the whole circuit even if some parts aren't simulate mostly to communicate better here

For instance ltspice don't have ti power management buck/boost or lm386/lm386 upgrades which is annoying or silicon chips (SI) frequency generators, analog stuff afaik

[late fulcrum]

It's annoying, but in my opinion, ltspice isn't the right tool for the job in either of those cases. The buck/boost chips have extensive documentation on how to use them, choose capacitors, inductors, and support components, etc. Someone else has done the heavy lifting (and probably by hooking up actual components and analyzing what they do with laboratory instruments instead of trusting a simulation that may be inaccurate).

An LM386 is just a speaker driver: squirt in a signal and hook up a speaker. Not much call for simulating that.

Then again, I've inherited some of Jim Williams' biases and don't bother with simulation much. I just breadboard things and see what they do for easy stuff like an LM386. If I fry one, a replacement is less than a dollar.

For switching regulators, I peruse the data sheets in detail and read the associated app notes, which contain a wealth of useful information.

[violet parcel]

Also for my charlieplexing the only alternative I see is doing it by hand and calculating all the nodes. Would prefer some software to do it for me and double check the actual amps in each led so I dont blow anything up

And of course how many total amps/voltage is required

[late fulcrum]

One advantage of current regulating LED drivers is that the current is known.

[violet parcel]

It seems to produced weird measures when I add a cap too

Like I dont understand why that cap would drop the voltage by 2.28V (battery is 4.999 something because of internal resistance, 1 ohm according to energizer)

I suppose the capacitor isnt correctly defined and drop charges too fast

Like a youtuber I follow always use it to explain the circuit and pull out a graph for A/C over time or a DC curve at different nodes like this:

Really help to understand stuff for me

like if you have diodes/transistors in it it's supposed to tell you are not providing enough voltage/current to them and would immediately identify a bad circuit

[late fulcrum]

It would do that at turn-on while the capacitor is charging. Which time step is that?

[violet parcel]

hum Ill try to find that answer. No idea what it means when it's in blue at circuit design.

[late fulcrum]

I don't either (I haven't used that tool)

[violet parcel]

doc says "The DC operating point analysis calculates the DC voltage and current of each node in the steady state of the electronic circuit.". I guess that make sense

[glad ruin]

Can confirm. This is part of my job at ADI.

[violet parcel]

since it's not charged the voltage is very very low

[late fulcrum]

I would expect that circuit to briefly flash the LED as the capacitor charges, and then finish with the capacitor at the full supply voltage and no current flow. But if the simulator is worse, it may impose a fixed forward voltage on the LED and subtract that from the capacitor voltage. If the simulator is better, it may simulate leakage through the capacitor and the resulting small current flow.

[glad ruin]

In LTSpice it all depends on what the diode model parameters are.

[late fulcrum]

It would probably take me a few minutes to key all that into LTSpice, and be left wondering what the time scale is and whether the model parameters are appropriate to the circuit. Whereas I can round up a power supply, capacitor, resistor, and LED and stuff them into a breadboard in a few seconds and get real world accuracy (which is what I normally do)

[violet parcel]

Guess I'll need to figure out why it acts that way with capacitors. Anyway I guess my circuit designer problem isn't solved only the simulation step (for analog circuits only). Fritzing became paid so Im looking for something else and fritzing dont have many chips I use

[violet parcel]

I guess the oscilloscope tells you all of this

[glad ruin]

Also you'd have to get those parameters in the lab, preferably averaged across a large number of parts.

[whole jacinth]

yeah, simulations allow you to test a variety of parameter variations that you might not have physical hardware for. physical measurements are still valuable, though, in case your simulations are waaay off

[late fulcrum]

I wouldn't even reach for an oscilloscope, a multimeter would be sufficient. Simulating it in my head yields what I described: the LED flashes briefly as the capacitor charges, after which the steady state is the capacitor remains at supply voltage and (essentially) no current flows.

I do recognize the utility of tweaking components and getting complicated data like resonance sweeps quickly with a simulator, but in real life I've never actually done so.

[glad ruin]

Simulations can be useful, during design. But after that you have to deal with the simulator's shortcomings.

[late fulcrum]

I have been known to look at a scope, realize "that waveform is not what I had in mind", hooking up a snubber network with a potentiometer, and tweaking it until the waveform looked right to me.

Then just reading off the potentiometer value and replacing it with a similar fixed resistor.

[violet parcel]

Seems like the reasons I have given so far dont convince madbodger but I also have no clues about components and also would help for training/education

[late fulcrum]

Oh, I understand your reasons, but I think you're trying to use simulation in ways where it's not going to help you

Like that wonky capacitor voltage reading would not help me understand much of anything

[violet parcel]

I think ltspice is too scientific anyway if you understand my meaning

like something happen but you dont know why

Where as Id prefer less scientific but knowing why

[late fulcrum]

Yeah, the "why" is the key to it all. Not an easy key to obtain, but worth the effort in my opinion.

[glad ruin]

LTSpice does document the conditions used for each simulation mode in the help.

[violet parcel]

yeah but doesnt seems to be what I was looking for (fritzing replacement actually using ISO circuit symbols that can also generate a pcb design). One I saw also let you interact with the circuit live, here I was trying to figure out how long I had of lighting once the circuit is off

[glad ruin]

That's going to vary considerably from part to part.

Voltage is a very ineffective way to control LED brightness.

[violet parcel]

Just want the led to not turn off instantly want I disconnect it but like slowly like a real car

[late fulcrum]

You can do that with a capacitor (as a timing component) and a transistor (as a voltage to current converter), or the way the car does with PWM (but that's a lot more circuitry)

But in most cases, it would be parallel capacitor instead of a series capacitor

Sort of like this current regulator I built a little while ago, but its job was to ramp the current up slowly (controlled by the voltage on the 1000µF capacitor charging)

Worked a treat, too

[violet parcel]

see this is exactly why I need a circuit sim

to see current and voltage over time to understand what is happening and avoid bad surprises (like a shock or a cap blowing up)

[late fulcrum]

I can understand how you may want a simulator, but I'm not sure you "need" one (I never simulated any of this, I just hooked it up and tried it). I've learned some basic rules to avoid blowing up capacitors (don't overvolt or overcurrent them, don't hook electrolytics backwards or to AC), and the maximum voltage of this circuit was about six volts, so no risk of shock

[violet parcel]

ok 😦 but I dont understand the time thing in a capacitor and Im worried that it will charge up much faster than it discharge and send a huge current to a led and blow it. I know I could add current protection etc. But nobody does that afaik because they understand the time constant of it

Transistor is the issue of voltage. Like I would prefer to not have a tesla coil level voltage without knowing / blowing my multimeter on voltage setting measuring it but it's rating at 640V and not 50k volts

[late fulcrum]

Neither capacitors nor transistors can create voltage. If your power supply voltage is X, you're not going to get more than X voltage out of a capacitor or transistor.

Tesla coils can produce high voltage because they're exactly that: coils. Coils can do some cool tricks, and boosting voltage is one of them.

[violet parcel]

was talking about mosfet transistors and NPN but maybe I understood wrong

especially if I was to try to repair stuff like audio equipment I cant tell at a glance which part might have a lot of voltage because I cant tell mosfet/transistors/caps just by looking. Like in the audio channel I had no idea those green things were capacitors

where as if I have the schematic in ltspice I would know by location the GND in the schematic vs the inside of the equipment

[late fulcrum]

Neither MOSFET nor bipolar transistors can boost voltage. Granted, I didn't always understand this either: when I was a kid, I saw a circuit that would let you change the tone of an oscillator by touching some contacts with your fingers. I figured it was powered by 9V, but transistors could amplify by a factor of ten, so I was afraid of possibly touching 90 volts. But that's not how it works, as I eventually figured out.

Yes, when you're repairing things, there can be a shock danger. And even recognizing parts may not help. A lot of designers will just 100V capacitors in several places, as it's cheaper to just use the same part instead of several different parts. But without knowledge of how the circuit works, you can't tell by looking which 100V capacitors might actually have a lot of voltage on them (especially if a circuit is broken, and voltage is getting to places it shouldn't)

And "ground" in the schematic can mean all sorts of things. In some circuits, "ground" is directly connected to the hot side of mains!

[whole jacinth]

if you switch capacitors between being in parallel and in series, you can produce a voltage boost (typically at low current), but it's not something you tend to do by accident

(https://en.wikipedia.org/wiki/Marx_generator for an extreme version of this idea)

[late fulcrum]

That's true: it's not something that commonly happens, and it isn't the capacitors boosting the voltage as much as the circuitry arranging them so their voltages add (like hooking batteries in series)

I used to work on a big (the size of a dumpster) Marx generator when I worked at the plasma physics lab, and it does exactly that: charges a bunch of capacitors in parallel, and discharges them in series, multiplying the supply voltage by (basically) the number of capacitors

The voltage on each capacitor doesn't increase, but the surrounding "circuitry" (in this case, ionized gas) acts as a bunch of switches to rearrange the capacitors so they're in series

[violet parcel]

Also accidental rf spark gap I guess can be any risk but not really possible with MCU power I guess (I might be exagerrating here - but isnt that when an inductor does when it arcs throught a switch?)

[glad ruin]

I assume this manual tuning approach works better for audio than it does in some other applications.

[late fulcrum]

In this case, (mis)using a switching regulator to drive a step-up coil for high voltage and high (out of human hearing) frequency

[violet parcel]

so if I had a pcb made from a schematic from an internet project and I have no idea what I am doing. What happens if they asks questions about it and I obviously cant answer ?

I think it's time to do it with a pcb from a credible youtuber and get acquainted with the rule check in eagle etc

[wispy granite]

Man i love those adafruit coasters. I was just thinking how i needed a coaster somewhere then i peeked in a box of stuff i got last week and realized i got a free coaster in it i have another one that i got a few years ago too

[rapid geode]

coasting throuhg life with your free coasters

[tame coral]

https://www.amazon.de/-/en/LEICKE-Universal-Power-Supply-Plug/dp/B07YVBHH6K/

would this power supply be sufficient for 12 servos on a pca9685

[urban arrow]

Howdy. Just curious as to HOW this works. I confuse easily.
After noticing this in a new code project, the SH1107 OLED I2C display was not even in the code, but it still displayed the terminal. So I set up the simplest code possible...
How does the board/code know what the "attached" display is, just because you set up the SPI bus?

[umbral phoenix]

@urban arrow has the MCU been reset since it last had a display set up?

(reset button, power cycle, or microcontroller.reset())

external displays are persistent across reloads, but not across resets

[hasty quarry]

I just found out about crystal oscillator load capacitance and I don't really understand why that's a thing

Is this correct?

An Adafruit article gave me a formula and 22 pF works for stray capacitance from 0 to 21 pF which seems like a massive range. I'm just scared I'm doing something wrong

[violet parcel]

Can you link the article because it seems that choice would be for a specific crystal with a load capacitance of 16 pF

If you have to provide the crystal here they would go for an average safe value for 16 Mhz crystal. So it seems some context is lacking

or you are asking why it has capacitance at all ?

[urban arrow]

No power cycle or reset this morning - thank you! I'm not losing my mind (yet). Just back from lunch and powered it back up - no terminal. NOW I get it 😀

[tardy badger]

So stray capacitance is hard to predict and can only really be accurately measured in board. This said, in general stray capacitance is pretty small with it being pretty normal to assume 3-5pF of stray capacitance. I tend to pick a stray of 3-4pF for two and four layer designs, less than 3 for boards with more internal layers.

Load capacitance is kind of an interesting topic too. Crystal has what we call a RLC equivalent representation which is pretty specific to the crystal circuit in the component. Generally there’s a dominant inductive source and a resistive load as well. In order for the crystal to then resonate at the given frequency it’s recommended to have a load attached at both sides of the crystal to appropriately match the represented circuit inside the crystal. The load capacitance then becomes important because too low or too high outside a buffered range of the load capacitance and you end up with a frequency that is either too low or too high.

There is probably better ways of explaining it, and perhaps Electroboom or others have talked about this more in depth

[hasty quarry]

That got pretty complex

[violet parcel]

Isnt it easier to look at load capacitance for a crystal in terms of particles and chemistry ?

Like a quartz crystal is SiO2 on the surface, an electronegative bond that try to resist giving electroncs to the other plate making it a very poor material for a capacitor. Changing the crystal structure of it with a voltage with two capacitors to pull charges (as they try to equilibrate two electroneutral metal plates) force the crystal to give electrons anyway which it compensate by vibrating back to it's electronegative equilibrum ?

[tardy badger]

https://www.analog.com/en/technical-articles/design-a-crystal-oscillator-to-match-your-application.html#:~:text=Basics of a Crystal Model,to the mechanical quartz resonator.

Regardless, yes you can look at it from the perspective of the composition of the physical crystal, but it’s far easier to model it in terms of an RLC circuit

[violet parcel]

that doesnt talk about electron/proton and positive/negative charge and how a piezoelectric align them though

[tardy badger]

For the average designer, that isn’t important

[violet parcel]

I was trying to understand how it differ from a regular capacitor with a insulator

[tardy badger]

There is going to be some inherent capacitance for the crystal and its supporting package circuitry (the semiconductor properties)

[violet parcel]

Seems like to figure out 0-20pF in the above I would have to know Ls (series resonance) and shunt resistance. But the series reonance depends on the physical properties of the crystal not given typically in a datasheet

so like Noe I have no idea how that schematics cames out with 0-20pF range

[tardy badger]

The ESL and ESR are going to have larger impacts on required load resistance in many cases, not withstanding shunt capacitance

[violet parcel]

This is for a 12Mhz crystal at 18 pF load capitance, ABLS-12.000MHZ-B4-T . So 27pf for both capacitors from the rp2040 design note make sense

[tardy badger]

Yes

[violet parcel]

but on the Noe schematic it doesnt. In my case the resulting CL is 16.5-20.5 for a target of 18 with the standard stray capitance between 3 and 7 pF

It also has a 50ppm frequency stability but I dont know how to convert from the above to ppm

Surprisingly most crystals datasheet dont provide the frequency vs CL range to adjust the frequency of the oscillator... Im kinda confused

[tardy badger]

ppm being how accurate you can expect time keeping to be under normal conditions (usually 25°C) from my understanding is more related to the quality of the physical crystal in the package

And the actual resonant frequency of the crystal is also tied to physical properties of the quartz crystal enclosed.

That analog article goes into a bit of detail about that as well

A pretty detailed primer actually

[violet parcel]

yeah was reading something similar by a company that make them: https://www.ctscorp.com/wp-content/uploads/Appnote-Crystal-Basics.pdf

[late fulcrum]

AdaFruit offers a useful writeup too https://blog.adafruit.com/2012/01/24/choosing-the-right-crystal-and-caps-for-your-design/

[violet parcel]

@late fulcrum since Im not sure that in #help-with-hw-design that creonico is convinced with my explanation for 100nF decoupling cap in the rp2040 design notes/if my answer answered their question. Can you tell me if this seems valid (provided by the youtuber I was talking about): . Blanked most of it because it's in french so I translated what seems to be the important points

[late fulcrum]

I'm not sure what to make of that diagram. I normally explain the common 100nF capacitors as a local source of power to satisfy quick current spikes without too much voltage drop.

[violet parcel]

Well I guess the question is, is it true that on a capacitor I want ESR to be near zero and resistance across it to be as much as possible ? So if a capacitor says esr 15 vs esr 0 I should throw it out

[late fulcrum]

Depends on the use case. Low ESR is often desirable, but how low is also situation (and capacitor) dependent. You generally want the leakage resistance to be high, but it can be surprisingly low in large electrolytic capacitors.

[hasty quarry]

This looks awesome

This is the most comprehensive prototype I’ve made in a long time

[tardy badger]

Driving 7 segment displays?

[violet parcel]

Didnt even know it was possible to convert a battery to AC:

[hasty quarry]

LED cube

[tardy badger]

Oh nice

[dusty citrus]

BRUH

HELP!!!

[violet parcel]

ah well project cancelled. I dont have a printer to reprint the galvanometer dial and the equipment to zero it

[dusty citrus]

I NEED A ANTI VIEUS

[hasty quarry]

Hey @tardy badger can you explain to me why I probably shouldn’t hook my LEDs up to my shift registers with no series resistor? I’m really insecure about their 1/8 duty cycle brightness, and the current resistances have them in theory getting 20-30 mA which even then is slightly above specs. But their brightness with no resistor at all looks good and seems like the maximum it can reach

What is really so bad about just doing that if they don’t seem to explode when I do

Their continuous 20-30 mA brightness looks great, but their 1/8 duty cycle brightness really does drag it down

[tardy badger]

Well, LEDs tend to draw as much current as the supply will allow without series resistors, which a shift register if I recall can do like 50mA output total across all the pins so. So you could likely end up drawing more current than the pins support. Which could damage the shift register

[violet parcel]

Also If on an MCU: that should be max 3 to 5 mA to not burn a MCU pin. But is actually lower in practice due to the max total pin mA as well depending on how many other pins you use.

[tardy badger]

Also damage the LED as a potential side effect

[whole jacinth]

check the datasheet for the max current per pin and total

the output drivers have intrinsic impedance as well, which could mean that your required resistance is lower, but they rarely tell you that directly (because it's often somewhat nonlinear)

[hasty quarry]

You almost gave me a heart attack but the 595 datasheet says 35 mA per pin

Is this property the maximum package current?

[tardy badger]

There should be a maximum for the entire chip

Looks like 160mA total

So ~20mA per output pin

If you use all them

[hasty quarry]

Ouch, on paper I'll have a maximum of 195 mA

[tardy badger]

I’d imagine 160mA total at 5V is going to be just shy of 1W dissipated

Which could get toasty

[hasty quarry]

Although that chart

[tardy badger]

I’d recommend like, a 5k resistor

[hasty quarry]

The second row is room temperature

I don't understand what that symbol next to A means

[tardy badger]

I’m fairly sure it’s supposed to be mu

Just looks weird