help-with-hw-design

[long wraith]

5Vo is the 5V boosted output from the battery. USB is tied to the microUSB 5V, so you’d want to connect your 5V charging source to that

[spice zenith]

Sounds good, thanks. Just wanted to be 100% sure. Given how hard RPi's are to get nowadays, I do NOT want to risk this one in any way at all.

[long wraith]

Safety good!

[rancid lagoon]

i just finished a little 6502 thing and i just thought to post it here before i send off the gerber in case i made any big mistakes

[supple pollen]

That's a really compact layout. You may want some decoupling capacitors. Assembling it will be fun with components on both sides.

[rancid lagoon]

I forgot the decoupling caps

Yes it will be “fun”

It’s only 2 chips on the bottom everything else is on top

I have no idea how it fit into 4 layers (for a sense of scale the board is the size of a 40-pin dip package thats 0.6 inches wide)

Thank the autorouter gods it worked

[supple pollen]

I figured you were going for that footprint

[grand quartz]

I'm trying to design PCB for a custom controller in eagle, How do I go about adding the Analog sticks?

[supple pollen]

If you can't find the matching part in some board or library out there, you may have to draw up a custom part and footprint (it's not too difficult)

[grand quartz]

where would I start looking?

[supple pollen]

SparkFun, AdaFruit, Microbuilder, and many parts producers offer libraries. There's also librarian software out there. Normally I just do a web search for the part number and "eagle" and see if something useful comes up.

[grand quartz]

How do I import the .lbr

oh wait nevermind

Thanks for the help :D

[sharp notch]

SnapEDA also is good and you can pay them to make a part/footprint/3d model if they don't already have it for download.

[sharp notch]

The parts I needed are checked into my inventory at jlcpcb, and I'm racking my brain on what else I could be missing/should triple check before submitting my 20 board order. I just found one thing which was the default settings wasn't including my via's in the solder mask, so I adjusted that in the DRC rules. What else might I be forgetting?

[dry pelican]

Is this a good footprint design for a Tesla coil gate drive transformer? I'm wrapping the coils around a 22.1mm OD 80 ferrite toroid, and this footprint will have the toroid laying down on the PCB and the wires going to the pads. The left side is for the primary, and the right is for the secondaries. Should I use this design, should I place the secondary pads closer together so I can twist the secondary windings together (which may reduce noise or noise susceptibility), or place all the pads close together so I can twist the primary and the secondaries together?

[sharp notch]

Well I spent the last 7 hours improving the routing and trace widths of my board. I hope these trace widths will be sufficient, namely 24 mil for VBUS, 20 mil for 3V3, and 10 mil for everything else. GND has its own pour on both sides of the board, but for visualization I have left that ripped up. I've verified the drill holes match the trace widths and that the DRC rules include all the vias in the solder mask. I've quadruple checked the footprints and the schematic. Getting very close to placing my order, reading through lists of beginner mistakes, etc. If you happen to see something wrong with this (I'll add the ground fill), I am all ears.

[limpid nest]

When do you pick a fet over a bjt for switching power

?

[hasty solar]

After some direction for creating adafruit-esque breakout boards for personal use. Adafruit have a breakout board for light sensor AS7341, I’d like to try out another sensor from the same company, the AS7343, but there are no breakout boards for it.. so I thought I wonder if I could make one!
Now I’ve no experience doing this but as I see it the adafruit board is a good starting point and work out if the new sensor needs different or additional circuitry.
Following from that I need to learn how to adjust the existing adafruit library to work with the new sensor, hopefully they’re similar enough for changes to be minimal…
Is it that ‘simple’ or does it seem like I’m missing something? As I said I’ve no experience really designing any circuitry so hopefully the similar adafruit board is a valid starting point!
Interested in any thoughts or opinions on how best to go about this little project

[sharp notch]

@hasty solar Do you plan to use Eagle or what software will you be using? In my experience the software used matters a lot, but my experience is from college 15 years ago and more recently the last month of getting my feet wet with Eagle again. In a month of spare time I have the above board that I think is ready to be built.

To answer your question though, it sounds simple enough with the right amount of time and the right tools.

[hasty solar]

No software yet! Need to have a look at what’s available. I’ve seen there’s a free browser based one that looks well featured but unsure what I’m looking for honestly

[sharp notch]

Well you can do a 2 layer under a certain size with Eagle free edition, otherwise Eagle paid is what I found to be the most "affordable" software that I would actually trust, but I am old school. I would have preferred Allegro but its like 6x the cost.

[long wraith]

Eagle has also been around for ages and from what I understand is very standard in the industry

[sharp notch]

Yeah for sure and you'll find a fair amount of footprints and libraries that are Eagle compatible, and you can pay small amounts to SnapEDA to make them for you if you aren't sure and can't find any. I was mostly interested in some of the more expensive software that is out there now (like Allegro) because from what I understand the auto-routing capabilities are a lot more advanced. Some may even have auto placement algorithms.

It took me about 100 hours to get comfortable with Eagle again, but that time was split across a wide range of the features. I thought how it manages libraries and parts is somewhat convoluted when I when I was getting started, but it works.

[hasty solar]

This would be my first ever pcb design. I think that it’s fairly likely (if I’m lucky) that it’s almost a swap out of the current sensor for the new one so I might be able to use most of the adafruit circuitry design but we’ll see!

[long wraith]

If it’s the same package and electrical soec, you could actually just order the PCB for the Adafruit one (They usually have all the files on the product page) to test and make any mods if necessary

[sharp notch]

Yeah, same pinout and everything.

[long wraith]

Nice. Really just needs the silkscreen changed to reflect the part change then, most likely

[sharp notch]

yeah -- it would be a good first intro to Eagle project 😉 Assuming you wanted to do a more complex board in the future, having stepping stones like this is useful.

[long wraith]

Unless you start with like, putting a battery connector, LED, resistor, and switch on a board… y’know, super simple circuits just to get a feel

[hasty solar]

Nice one, thanks for the input 😁 if it’s just a job of swapping out the sensor that would be amazing but we’ll see! 🤞 should be a fun little project either way!

Have no idea where to start creating a library for it but I’ll cross that hurdle later!

[spare galleon]

would anyone be willing to look over my (messy) modification of the esp32 feather schematic? i've added the following:

• gps
• gyro/accelerometer
• pressure sensor
• microsd card
• power output terminals

[sharp notch]

I mean I could look at it, but I don't know much about the esp32 yet.

[rancid lagoon]

do you see any glaring flaws before i send this to oshpark?

[sharp notch]

What are all of those vias about @rancid lagoon ?

I just ripped up my board layout and am re-doing it, full manual this time.

[rancid lagoon]

the xtal pins and the filter cap are on the bottom

i need the xtal pins to program the attiny

[sharp notch]

Its hard to tell from that image but the traces running between those pins, that would bother me. How wide are the traces? Not a lot of clearance there.

In J1

[rancid lagoon]

the kicad default of 0.25 mm J1 is the ICSP header

the board size is 0.8 x 1.2 inches so scale is a bit weird

[sharp notch]

I just mean if there was more space between that and that smt mount you might be able to route the wires less close through the pins.

[rancid lagoon]

why not? would it affect the circuit?

[sharp notch]

Perhaps not, but if there are clearance issues with the drill holes, it could. I am fairly new to the manufacturing side of things.

[rancid lagoon]

this is the 3d render (i changed R1 from THT to 0603 SMD)

[sharp notch]

That helps me visualize it better for sure

[rancid lagoon]

i looked at the oshpark previews and it looks fine

and here is the 3d render without the parts

[sharp notch]

Its probably fine, you should seek an additional opinion though. What is the trace widths on those?

[rancid lagoon]

0.25mm

the kicad default

[sharp notch]

Are they all logic lines?

[rancid lagoon]

it's a small battery powered project so current isn't a issue

[rancid lagoon]

wym?

[sharp notch]

As opposed to voltage supply

To J1 I mean

[rancid lagoon]

i'm using the ground plane for the ground trace and the battery voltage goes straight to the attiny

[sharp notch]

What do the switches do?

[rancid lagoon]

wait i just noticed the battery is meant to be soldered in so the 5v from the icsp would fry the battery

[rancid lagoon]

pull down logic lines (i'm using the internal pull-ups of the attiny84a)

i forgot a diode

since the diode has a voltage drop i wonder if i should go for a 3AA battery holder instead of 2AA's or i could just take out the battery when programming

[sharp notch]

I think its a shottky diode has a lower voltage drop? well 2 AAs is only 3V and 3 is 4.5V right? so-- if you're aiming for 3.3 you're not going to get a 1.2V drop from a typical diode.

I had a strange outcome earlier, my board was rendering fine in the quotes but I reworked it right, so I flipped a row of 8 connectors to the back side of the board and the ones on the back I flipped to the front, now the default CPL export renders in the board house upside down, but if I flip the orientation in the CPL by 180 degrees it renders correctly. But it renders correctly in Eagle without any of that, and I dunno which thing is correct -- should I trust the preview rendering of the board house and cater to it by modifying the CPL file orientation?

[rancid lagoon]

the attiny can go down to 1.8v i just want the led to light up

[rancid lagoon]

CPL?

[sharp notch]

If it can go down to 1.8v I would stick with 2 batteries.

[rancid lagoon]

what does CPL mean?

[sharp notch]

The CPL (Component Placement List) This file specifies the exact position, rotation and on which side of the board each component reference designator needs to be populated.

Also called a pick and place file.

[rancid lagoon]

oooo

[sharp notch]

It's basically a csv of data

[rancid lagoon]

it tells the pick-and-place machine where everything goes

[rancid lagoon]

i would probably try to figure out the cause (try to replicate it on another board) and fix it but if you need to i would trust the board house and modify the cpl

[sharp notch]

That's a good idea and also a sign to sleep on it. Should always have a good nights rest before pushing the PCB order, I mean its my first one, but start strong.

In college I designed a schematic and my buddy routed the board and we sent it out and it worked, so I am hoping to be as lucky doing it myself.

[rancid lagoon]

i'm only a teenager and this is also my first time ordering one which is why i'm asking here (i've designed a few that are in various stages of completeness from pretty much done to barely a concept that i probably won't finish)

[sharp notch]

Oh wow, you're that young? That s super impressive you have an interest in making boards. I am 37, went to University of Illinois for ECE.

[rancid lagoon]

the way i do electronics is pretty much "if it can be done it software it will be done in software even if it's a pain (with a few exceptions i don't think you can code a reset pull-up resistor)"

[unreal flax]

Heh heh. You're going to be deadly once you sink your teeth into FPGAs, then.

[rancid lagoon]

i've had my eyes on FPGAs for a while but never actually got into them (pricy)

[unreal flax]

Have a look at the Tang Nano boards... super-cheap.

[rancid lagoon]

oooo

[glad lynx]

You're lucky. When I was a teen, you couldn't order small batches at a reasonable price, so I had to learn to etch my own boards. Most of them were drawn with Sharpie resist. They are horribly ugly, but they work. I was so happy when I discovered photoresist boards!

[rancid lagoon]

that is a good skill to know (probably one of the cheapest ways to make flex pcbs too)

[long wraith]

Every board I’ve ever designed I did on paper and etched by hand, lol

[glad lynx]

Indeed, and I'm really glad I learned it, but it would have been really nice to be able to order more...professional boards.

[sharp notch]

@glad lynx I remember etching boards in college, we used a school projector and printed on the projector sheet what we wanted etched. The chemicals are not fun.

[glad lynx]

Once I graduated from Sharpie, I did some with inkjet printed transparencies. The chemicals are definitely not fun, but it turns out so much nicer than Sharpie!

[rancid lagoon]

without CAD all of my designs would not exist (i'm kinda lazy when it comes to IRL design (CAD is a different story sometimes i'l stay up late trying to route that one trace (you know what i mean) that the autorouter couldn't(yes i use an autorouter(yes i am nesting parenthesis))))

[glad lynx]

Yeah, I was really happy when I learned KiCad. Hand drawing circuits is a horrible pain.

[spare galleon]

how would i hook up this 3 pin power switch to my battery input?

[glad lynx]

I would depend on the switch type. If it's a two throw switch, pin 2 probably goes to your electronics and either pin 1 or pin 3 goes to the battery. You might also connect the unused pin to ground, but it depends on what you are trying to do and whether 1 and 3 are internally connected or not. (Alternatively, you could do battery -> device -> switch -> ground/-battery.)

[rancid lagoon]

peppperoni505 you've been running vscode for 9 and a half hours?!

[glad lynx]

(You would think this would be a simple question, but it's kind of not...)

[spare galleon]

it's been running in the background 😅

(i leave my computer on)

[rancid lagoon]

i would go for the SPDT switch symbol and set the footprint to the switch you want to use to make wiring and understanding the circuit easier

[glad lynx]

Yeah, this is probably the best plan.

(I found three pin switches confusing when I got my first one as well...)

[rancid lagoon]

i would recommend you watch the electroboom 101 series by electroboom on youtube (it's educational and fun to watch him shock himself/blow up capacitors)

[spare galleon]

haha - i'll give it a watch

[long wraith]

This implies people turn their computers off…

[glad lynx]

I generally do after a kernel update, though is rebooting really turning it off?

[rancid lagoon]

i would keep mine on 24/7/365 except for the fact my computer is called a "laptop" so it has this thing called "battery life" and my external hdd halves this "battery life"

[glad lynx]

I keep mine plugged in!

[long wraith]

Psshhh, battery life… plug it in, plug it in!

[rancid lagoon]

i have to turn it off to transport it to the mobile fast unlimited hotspot called "car"

[spare galleon]

aside from my switch situation, is there any way to check how royally i messed up my schematic? as i mentioned earlier i used the feather v2 as a base and added a lot

[glad lynx]

Yeah, I remember when I was a student and had to take my laptop places. There wasn't really any other option aside from turning it off.

[long wraith]

You can get an inverter to power it in the car XD or a chonk external battery

[rancid lagoon]

wym?

[long wraith]

sleep

[rancid lagoon]

my mobile hotspot comes with one built in

[spare galleon]

my first time designing a pcb, so i've probably wired some things (if not everything) wrong

[glad lynx]

Linux didn't handle sleep that well back then.

[long wraith]

Unlimited power

[rancid lagoon]

if you're using kicad it won't allow you to connect traces to stuff they aren't supposed to connect to

[spare galleon]

im using eagle

[rancid lagoon]

both the hotspot and outlet turn off when you turn the mobile hotspot off to refuel it

[glad lynx]

Lame.

[spare galleon]

i guess the better question is how do i ensure this design will work before i spend the money and time getting it manufactured

[rancid lagoon]

we have a linuxer among us (i am one of the fabled people as well)

[long wraith]

Just need a battery

I Linux too XD

[rancid lagoon]

the hotspot part tho

[spare galleon]

i would use linux if it the games i played ran on it

for me thats a big issue

[rancid lagoon]

another of the fabled

[long wraith]

Use your phone!

[rancid lagoon]

i can't download 150gb worth of flight sim on 0.6 mbits/s (yes i used up the 15gb already)

[glad lynx]

I do have a Windows computer, for the games. Lutris and Steam handle most of what I play on my Linux laptop, but there are some exceptions.

[long wraith]

0.6Mb/s?!?! Where are you, Narnia?!?!

[rancid lagoon]

throttled hotspot

[glad lynx]

Narnia has magic. I'm sure you can get better than that there.

[long wraith]

Fair

[spare galleon]

would something like this work?

[rancid lagoon]

i would have wiped win 11 off this laptop and replaced it with linux mint if not for 4 reasons
1: i'm lazy
2: it came with the computer pre-licensed and windows license expensive
3: games
4: i am dual-booting with linux so i have it and windows

[glad lynx]

@spare galleon That looks about right to me.

[long wraith]

You should upgrade to Windows 10

[spare galleon]

i feel like im the only one who likes win 11

[glad lynx]

With those three pin ones, one pin is usually left floating.

[spare galleon]

thanks!

thanks dyno

[long wraith]

You are… it’s ok, you’re allowed to be wrong

[rancid lagoon]

no he's not alone

[glad lynx]

Lol! Recently got a Windows 11 laptop for the kids, and it was a nightmare to setup.

[spare galleon]

i love the design of it

(this is coming from someone with a love for macos)

[rancid lagoon]

also my last message was flagged as spam by dyno because i put one too many 9's in it

[glad lynx]

Had to install a program to replace the task bar with the Windows 10 one, just to get it to not group tasks.

Lol!

[long wraith]

I hate the look, but my biggest gripes are performance, security, and random weird stuff

[spare galleon]

perf has been fine for me

[long wraith]

I don’t find MacOS super visually appealing XD

[spare galleon]

nothing worse than windows 10

[rancid lagoon]

NO win 11 is much better than win 10 (i've used both and wiped win 10 in a heartbeat (more like it self-corrupted (it actually did explorer.exe was throwing some error about some instruction so it constantly restarted)))

[long wraith]

… child, have you not used ME

[glad lynx]

I liked Windows XP. I didn't switch to 10 until 2019.

Oh, ME was definitely the worst!

[spare galleon]

???

[long wraith]

Windows ME… one of the worst operating systems of all time…

[spare galleon]

i have never heard of it

so i guess whatever they did to hide it worked

[long wraith]

Oh sweet summer child

[glad lynx]

Windows ME is pretty much the worst Windows ever. The only thing it did right was mounting multiple partitions on partitioned USB drives.

[rancid lagoon]

search windows ME (it's windows: millenium edition so let that tell you about it)

[glad lynx]

(I was a tech during the ME era.)

[spare galleon]

it cant be that bad

[rancid lagoon]

you have been blessed

[long wraith]

HAHAHAHAHAHA

[glad lynx]

Oh, it can!

[long wraith]

OH IT IS BAD

[spare galleon]

i am not getting much from these screenshots

[rancid lagoon]

uh oh you just declared war against everyone here

[glad lynx]

Lol!

[long wraith]

You couldn’t pay me enough to use ME. I don’t even play with it

[glad lynx]

To be fair though, Vista does get close.

[long wraith]

Vista shudder

[rancid lagoon]

it's the last of the 9x line (windows 95, 98, and me) it was buggy, unfinished, looked like someone copied win 98 and changed just enough to call it different, and more

WHO UTTERED THE WORD "vista" THAT WORD IS CURSED (yes i have a history with the OS)

[long wraith]

ME was a crime against humanity

Vista is also a crime against humanity

[glad lynx]

I actually wrote a blog post about Vista being a beta test where you have to pay to participate. Then when Windows 7 came out, people started saying that it's like Vista was the beta for Windows 7. Yeah...

[long wraith]

7 is what Vista should have been

[glad lynx]

Indeed. (And in my opinion, even 7 wasn't that great. Vista managed to make it look really good though.)

[long wraith]

7 was good… but when 10 came around? YEET

11 is going backwards

[glad lynx]

Indeed. Removing the good features and adding a bunch of things no one needs.

[long wraith]

Change for the sake of change is not good

Also it’s ugly

[rancid lagoon]

sounds likely (someone probably mixed up some files so some executive thought vista was the full release and started marketing it and the scourge that bears the name "vista" was unleashed onto the world to the horror of IT professionals and people with eyeballs alike)

[long wraith]

No no, Vista had been under development for years… pre-planned to go out… it was just bad

[glad lynx]

One of my friends pointed out that MS goes through a cycle, where it adds a ton of a low value features and makes unpopular changes for a few versions, until too many people are complaining about poor performance and lack of good features, then they cut it back and streamline it for one release before starting over.

Yeah, I wish my tongue in cheek suggestion about Vista being a beta was true, but sadly it wasn't.

[rancid lagoon]

win 10 was the latest of the bad versions win 11 is the cycle starting again

[long wraith]

… windows 10 has some of the best performance and built on top of 7 in terms of features and compatibility

[glad lynx]

No, Windows 10 is the one where they cut back. Compare memory footprint and hard drive space to the previous version.

[rancid lagoon]

my first windows version was 8.1 tho so roast me

[glad lynx]

11 isn't as bad as the +1 after that usually is, and there are some good things, but there are a ton of bad things as well.

[long wraith]

Eww

[glad lynx]

My first was 3.1, and at one point I used 3.0 for a few years. I remember when Windows wasn't even an OS!

[rancid lagoon]

win 11 is the one after the clean restart so it's still good but is starting to show signs of bad things to come

[glad lynx]

8.1 is a harsh place to start.

Right, that's what I'm getting at. Windows 11 is still better than most Windows.

[rancid lagoon]

it was my first laptop when i was 5 ok i didn't know about the freedom of linux yet

[long wraith]

I couldn’t use 11 because of the dumb UX changes, plus a number of my tools just… don’t run. Because Microsoft.

[glad lynx]

Lol! Hey, I was in my 20s before I discovered Linux, and it took nearly another decade before it was my primary OS.

[long wraith]

yeah let’s just break compatibility we’ve had since NT.

[glad lynx]

The UX changes are the big issue in 11 for me as well.

[rancid lagoon]

i like the new UI

[long wraith]

It’s gross and mushy and fat as far as I’m concerned, lol

[glad lynx]

It's not the UI so much as removing a bunch of customization features that are important for productivity. They basically made a lot of defaults the only option, and they weren't good defaults, especially for power users.

[long wraith]

10 is so clean… not perfect, but much better

[rancid lagoon]

i do like the more rounded theme it has over windows 10

[long wraith]

I like sharp

Windows 2000 noises intensify

[glad lynx]

Yeah, the theme is fine. I would rather a steampunk theme, but I'm not horribly picky. (At least, as long as they don't do something dumb like put the title bar controls on the wrong side...)

I always reverted my XP taskbar to the WIndows 2000 look.

[rancid lagoon]

i do like the new task manager UI (it needed a dark mode)

[glad lynx]

Ug, the centered taskbar buttons.

[long wraith]

The start menu in the middle is just such WHYYYYY

[glad lynx]

At leat that can be fixed though.

[long wraith]

That’s one of the weird things I’ve hated about MacOS

[glad lynx]

No, there's a solid UX reason to put the start menu in the corner. It's much easier to hit with the mouse when it is in a corner, because you don't have to aim carefully. Just swipe the mouse down left far enough, and you are there. Putting in the middle makes it much harder to aim for.

(My CS degree included a whole course on UX, and this is one of the things we discussed.)

[rancid lagoon]

happy now? (i never really liked the icons being off-center)

[long wraith]

The start menu also is just massive and full of garbage you can’t get rid of for no reason

[rancid lagoon]

imagine if you could set the taskbar to be on the right

[glad lynx]

Yeah, XP's start menu was the last good one, and 8 totally jumped the shark. The search feature is nice though.

[long wraith]

https://tenor.com/view/get-out-leave-gtfo-get-out-of-here-gif-6207127

[rancid lagoon]

the 8 start menu was good for touchscreens (my laptop had one but it is now broken thanks sister)

[glad lynx]

Prior to 11 (maybe before 10?) you could! Only a monster would, but on XP at least, you could put it on any edge.

[glad lynx]

Right, but not for anything else. It's like MS was all, "Let's make Windows for tablets" and forgot that anything else even existed.

(That said, even for touchscreens it was rather bloated by default. No one needed most of the default stuff.)

[rancid lagoon]

yes finally someone understands that

[glad lynx]

Hey, I'll give credit where it is due. Even a dumpster fire can keep homeless people warm.

[rancid lagoon]

i just realized we've been having a conversation about windows UI elements in the #help-with-hw-design channel

[glad lynx]

Yeah. Ironic? Perhaps.

[long wraith]

I am not responsible for this

I should sleep

[glad lynx]

Lol! I'm not too worried, as long as we aren't preventing people from getting help when they ask.

[rancid lagoon]

i'm testing out explorerpatcher and this looks WEIRD (and yes i slightly panicked which is why taskmgr and cmd are open)

[long wraith]

It’s the gross icons

[rancid lagoon]

this is hurting my brain

this is a wave of nostalgia

[long wraith]

Try Windows 3.11 and see how your brain fairs, lol

[glad lynx]

ExplorerPatcher is exactly what I installed! I can't stand task grouping. It makes task navigation really slow when you have multiple browser, terminal, and editor instances open.

Windows 11 won't allow you to disable task grouping, so I found a way to fix it.

[rancid lagoon]

i'm not old enough

[long wraith]

I’m surrounded by children

[rancid lagoon]

the oldest version for me was xp

[glad lynx]

Lol!

I liked Windows 3.11.

[long wraith]

3.11 is actually a favorite classic

[rancid lagoon]

how were your eyes not exploding? other than that 3.11 is nice

[long wraith]

Let’s have a challenge where the kids have to use all the old stuff for a week XD

[glad lynx]

Let's indeed! Livestream it.

[rancid lagoon]

I CALL USING AN OLD COMMODORE MACHINE

[glad lynx]

Lol! The first computer I owned was a 286 with Windows 3.0.

[rancid lagoon]

i may be young but i'm still a nerd for all things retro

[glad lynx]

Lol! Yeah, like, I wouldn't want to use it for my main work machine, but it's fun to play with.

(That said, I'm comfortable even in just a bare terminal, though having a browser is pretty important for work.)

[long wraith]

I forget my first computer, but I think it was an 8086

[glad lynx]

Well you win then.

[long wraith]

Lynx time!

[glad lynx]

I've done it before!

[long wraith]

Hehe

The kids will SUFFER without a GUI

[rancid lagoon]

that's stone age compared to today

[long wraith]

Indeed

[rancid lagoon]

...i called the comodore m8

[glad lynx]

Seriously!

[rancid lagoon]

you realize i'm a kid (in that context) right?

i can live without a GUI for a week

wait no

commodore machines can run GEOS

[long wraith]

I could live without computers for a week

[rancid lagoon]

sure you could

[long wraith]

Bet you can’t

[rancid lagoon]

toss me a c64 and a few datasheets and i'm set

[long wraith]

C64 is a computer XD

you’d probably implode with no computer

[glad lynx]

I've been known to go without a computer for a few days at a time, but I don't prefer it.

[rancid lagoon]

toss me some vacuum tubes and i'l have a blinking light by the end of the week

actually don't toss them just hand them to me

[long wraith]

Lmao, that’s still getting into computers

[glad lynx]

Does it count if you build it yourself?

[long wraith]

… yes?

Hmm

Let’s just say “no technology”, exception of lights

[glad lynx]

Lol! Hmm, not sure I have enough transistors for a 4 bit processor, but I could probably make a few adders...

[rancid lagoon]

something's off

[rancid lagoon]

how do you power them?

[glad lynx]

LEDs? That gives me diodes... Actually though, technically I know how to make diodes and transistors from copper and lead...

[long wraith]

lights and accompanying power

[rancid lagoon]

perfect

i can make some diode logic

[long wraith]

Actually let’s just CAMP CAMP for a week, the OLD FASHIONED WAY, with NO electronic technology

[glad lynx]

Oh, relays. Can I have magnets? I know how to make diode relays with magnets, flexible metal, and some wire. From there, digital circuitry isn't too hard (though very power hungry and slow...).

[long wraith]

Everybody gets a tent, knife, sleeping bag, and food in cans

[glad lynx]

Lol!

[rancid lagoon]

how do we open the cans?

[glad lynx]

Mind if I make some charcoal, build a forge/smelter, and find some ore?

Rocks.

[long wraith]

Pull the tab

[glad lynx]

Lol!

Oh right, with a magnet, I can extract iron dust from soil.

[rancid lagoon]

we over here restarting civilization

[glad lynx]

Lol! Indeed. I like to study old tech, and I'm not talking only 50 years old either.

[rancid lagoon]

ye ancient tech

[glad lynx]

Yes, that.

[long wraith]

I know how to restart civilization XD

[rancid lagoon]

we restarting the modern world starting from the roman era

[rancid lagoon]

press the reboot button

[glad lynx]

Oh, that wouldn't be too hard. The Roman Empire is a really solid starting place!

[rancid lagoon]

i meant to say era

[long wraith]

https://tenor.com/view/spongebob-squarepants-spongebob-patrick-star-rebooting-reboot-gif-4770991

[glad lynx]

Lol!

Well, that escalated...

[rancid lagoon]

you unplugged it so it would reboot it

[long wraith]

I need to unplug my consciousness

[glad lynx]

Man, I need to make a new forge/smelter. I had to leave my old one behind when we moved a few years ago.

[long wraith]

My forge exploded

[glad lynx]

Hmm, that sounds...fun?

[long wraith]

It was exciting

[glad lynx]

I'll bet! Gas or charcoal?

[long wraith]

Solar reflector

[glad lynx]

(Or, inductive! I haven't done that yet.)

Oh nice! I haven't done that either!

[long wraith]

Do not recommend XD

[glad lynx]

Lol!

[rancid lagoon]

we're kinda back on this channel's intended topic

[glad lynx]

Yep!

Kinda

[long wraith]

It’s hardware at least, lol

I need sleep… nini peeps

[glad lynx]

Later. Sleep well!

[rancid lagoon]

we went from helping someone design a pcb to fighting about windows to restarting civilization to exploding smelter

sleep well

[glad lynx]

Sounds like a complete day to me!

[rancid lagoon]

we both should probably hit the hay

it's 11:45 right now

unless you live in china or smthn and you just got up early to talk

[glad lynx]

I'm pretty far west, so I still have a few hours, but sleep well!

[rancid lagoon]

gn time to mess around with the computer for the next 15 minutes

[glad lynx]

Later!

[rancid lagoon]

cya tmrw

[bleak cosmos]

hey guys, i need some help with creating a pcb

i had a project and i want to improve it's feature. I used arduino uno at first but it doesnt have the potential that i need

[spare galleon]

can you give more info

[bleak cosmos]

im writing it, give me 15 mins

• usb-c 5v 2A to power the curcit and charge the battery
• 1 SCL and 1 SDA for connecting 2 I2C devices (mpu6050)
• 4x analog inputs and GRD (it is currently 2 for now, but it will be upgraded in the future and use 4)
• GRD and 5v input to power the curcit and recharge the battery
• 4x (GRD and 5v output) to power the other components (2x flex sensors) (2x mpu6050) (1x bluetooth device "undecided yet")
• 2x digital input and GRD (for 1 button and 1 switch)
• 2x (100k ohm resistance) for the flex sensors
• microcontroller "not decided yet"

Goal ->

• must be able to connect to windows and android through bluetooth
• must not use an external program (plug and use)
• input the movemnet of the mouse (all 3 axises + 3 buttons)
• switch to keyboard mode once the computer/android device enter writing mode
• button should recalibrate the gyroscope
• swtich should turn the cuircut on and off, but doesnt enterfeire with charging the battery

main device ->

• a glove to move the mouse depending on the movement of the user's arm
• drawing the letters on a flat surface should write the letter on windows/android

[rancid lagoon]

so you want a combination mouse/keyboard/gyroscope that uses bluetooth HID?

i don't think that switch to keyboard mode function is possible in just software

combination things like that mimic both at the same time

do you want 2 mpu6050's on the board at once?

on the microcontroller part a rp2040 stamp would probably work well

i might be able to put something together in kicad later today

[bleak cosmos]

yes 2, one will be place at the top of palm of the hand, and the other a bit under the shoulder. I already tested it on arduino uno, and reading both at the same time is possible

[bleak cosmos]

in this case, we can add another button to switch between them

[rancid lagoon]

I can make the schematic but you will have to make the pcb so you can lay them out how you want

The rp2040 stamp also works with circuitpython so coding will be easier

[bleak cosmos]

great, it would mean alot to me

[rancid lagoon]

np

[rancid lagoon]

also you will have to do the code as well

[rancid lagoon]

should one button recalibrate both gyros at once or one button for one gyro?

also that switch part will have to be done in software so when a pin goes low it puts it into a loop effectively turning it off

[fervent lance]

why am I missing the "panelize" button?

on kikit

[rancid lagoon]

what software is that?

[fervent lance]

kikit on kicad

[rancid lagoon]

i've never used that so sorry i can't help you (some googling might help)

[bleak cosmos]

which language tho?

[rancid lagoon]

arduino or circuitpython

you pick

[bleak cosmos]

this is a software thing, but yes both

[rancid lagoon]

just making sure

[bleak cosmos]

sounds perfect to me

I'll head to sleep now, it's 1:40 am and I got classes tmrw. and again thank you so much for ur effort @rancid lagoon ,and good luck 👍

[rancid lagoon]

ok

i'l dm you with details/further questions and the finished .zip

[bleak cosmos]

aight

[eternal fox]

Quick question: Can you use VIA's to connect things like kaihl hotswap sockets to traces that go on the other side of the PCB?
Like rows go on blue side, collumns go on red side (kiCad)?
Trying to get the routing to be done in a nice fashion. Im currently working with this:
Would that be possible or am i askin for problems by doing this?

Or if anyone has a basic ortho (65%) base with an rp2040 mcu that i can look at that would be absolutely fantastic 🙂

I assume you wire it up to the MCU just as you do normally. Id love to make it look nice and have something to draw inspiration from but its hard without having the pcb in hand really.

[rancid lagoon]

Yes

A via inside another pad isn’t an issue if they are on the same net

It might get filled with solder when you solder on the switch but that isn’t an issue

[wicked root]

https://reddit.com/r/wholesomememes/comments/z6rwwi/its_nice_to_have_someone_who_believes_in_you_3/

[worldly schooner]

Looks fine, though if you don’t include diodes your keyboard will have ghosting issues.

[fervent lance]

in the end the button was always there but I wasn't seeing it

[supple pollen]

I know that feel

[eternal fox]

Another Kicad question: Each layer can only hold one layer of tracers, right? I cant have one blue tracer going over another blue tracer without them touching, right? I assume the tracers are developed from one single sheet of copper and that the kicad intersect-graphics are only there to confirm that you have indeed connected one tracer to another tracer?

[unreal flax]

Correct. One layer is literally one physical sheet of stuff in the board, whether it's ink or copper.

[eternal fox]

Nice, good to know 🙂 Thanks m8!

[dry pelican]

This is my second PCB design for my Tesla Coil power driver circuit. It’s a half bridge, but it will be able to be configured for full bridge operation. I just want to know if the layout and traces are good or if there are any glaring design flaws. It’s not a final version, as I still have to clean it up, and add some more information on the silkscreen.

Some things I will also change in the next version: add a separate power rail for the mosfet driver (so that I can feed it with a higher voltage) and maybe a 12v regulator for the fans. Maybe remove C6 if it would cause worse performance. Possibly add some fly back or TVS diodes to the FETs, although that might be outside the PCB.

PVCC voltage: 12-31V (maybe more if I can get a beefier PSU)

[supple pollen]

I'd keep the protection components nearby, at those frequencies

[dry pelican]

The mosfet driver output clamping diodes?

GDT: 8:12:12 or something around an 80 21.1mm OD ferrite toroid

Phase jumper: allows you to select phase of output (when two are combined for full bridge or performance is better if phase is switched)

C6: filtering high frequency harmonics that could cause bad operation? (I don’t know if this will work)

EN: input from interrupter

IN: input from feedback or oscillator circuit

Prim1: goes to the primary coil

Operating frequency: 1.3 MHz or lower

Here’s how prim1 connects to the Tesla coil primary. I’m using 10uF cylindrical pulse caps (rated 250v I think) because I got a good deal on them. It’s probably overkill, but I think they’ll work fine.

[supple pollen]

Why are you AC coupling it to both PVCC and Pgnd?

[dry pelican]

To provide a PVCC/2 point that is capacitively coupled so that there is no DC component over the inductor that would waste power. I can’t use resistors because that would be wasteful, and all I have is a bench top power supply. I don’t have a variac, and at don’t want to play with rectified mains power. Most other half bridge sstcs do this. For example:

[idle python]

whats the pitch connector used for DSI in the cm4io board i want to use the same one

FH12-22S-0.5SH(55)

found it

[supple pollen]

That won't provide PVCC/2, since capacitors block DC.

[dry pelican]

What I meant was a capacitor divider. It will let AC through, but block DC. The point is to block DC so that an almost purely AC current can flow through the primary rather than what would happen in a single mosfet (not class E) coil where there is a DC component always on the inductor that is shorted by the inductor and creates power loss. (As I understand it)

[supple pollen]

It will do that, but it will do nothing to set the voltage (which will basically be set by the voltage at the other end of the inductor). So electrically a capacitor (of appropriate value) to ground would be the same (and easier on your power supply)

[dry pelican]

So the capacitor from PVCC to the inductor can be removed. That makes sense, but then why has every half bridge coil schematic I’ve seen use two caps in series with the primary in the middle?

[supple pollen]

I can only guess, but my thinking is someone did it once for some reason (valid or not) and then everyone copied it (this happens with many designs)

[dry pelican]

makes sense. My guess (other than the copying designs theory) is that it acts as a capacitor divider as well as a DC blocker that provides a virtual ground to the primary.

[supple pollen]

While it is possible to build a capacitive divider for AC signals, that's not what this hookup is going to do.

[rancid lagoon]

for some reason i've never thought of a capacitor divider

it makes sense in theory but for some reason i've never thought of the idea

[supple pollen]

Oscilloscope probes are possibly one of the most common uses, consisting of a resistive divider in parallel with a capacitive one, to achieve linear scaling across a wide range of frequencies, often DC to tens or hundreds of megahertz.

[dry pelican]

Another guess as to why the series capacitor configuration exists is because the top capacitor will pass current when the bottom mosfet switches on, and the bottom cap will pass current when the top mosfet switches on. But the bottom cap will also discharge, passing current through the primary, when the bottom mosfet is switched on.

[supple pollen]

It doesn't really happen that way. Both capacitors pass current at every switching. But basically when the bottom MOSFET switches on, the top capacitor will get charged and the bottom one will get discharged, and current flows through both of them in the process. When the top MOSFET switches on, it reverses, and the top capacitor gets discharged and the bottom capacitor gets charged, and again current flows through both of them. You'd get the same behavior and amount of current with a single capacitor (with a value of the sum of the original two) to ground (or to the supply voltage), as it alternately charges and discharges.

[supple sky]

I have been trying to find a good "pillow speaker" for a few years now. I've landed on a bluetooth conductive speaker that works great, the only thing is it doesn't work while it's charging. Simple enough right? Not really, I forget to charge it a lot so I ordered a switching DC charger so I can keep it plugged in and switch it on to charge. This is also kind of annoying though. I was researching ways to make it work while charging but always seem to find articles that discussed fixing chargers and not solving the problem I have. Has anyone ever done this? Is there a place I could get some more information or technical phrases that I could use to find more specific information this type of mod?

[supple pollen]

What type of mod do you have in mind? Continuous charge? Just powering it from DC? Something else?

[fervent lance]

I just snap my USD $3.00 headset (plastic) in half and give each earpiece a twist to remove 'em. Shove under the pillow: done.
I stock up on 'em when I hit up the V.A. Patriot Store ;)

[supple sky]

Thank you!

[supple sky]

Just powering it via DC power, I think if charging is what shuts it down I could stay away from that. Here's what it is https://www.amazon.com/dp/B09JKWFQNH?psc=1&smid=A2PZN8Y1QOG9D1&ref_=chk_typ_imgToDp I'd be willing to buy something else if it's a better solution. I ordered another one so I can tear it apart to try to make it work while plugged in lol.

[supple sky]

I actually have used regular headphones like this before and my girlfriend is an extremely light sleeper. Regular headphones are very high pitched and you can hear them, plus, I like it to be bluetooth if possible because sometimes I watch youtube while she's watching something else lol.

[supple pollen]

I tend to avoid amazon stuff, but the basic approach is to hook the power supply up as if it were the battery. Here's a video about someone converting a phone to run on an external power supply https://www.youtube.com/watch?v=7f8SliNGeDM

[supple sky]

I've actually built a little bluetooth speaker myself using this https://www.amazon.com/gp/product/B086GDNR72/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1, it didn't work that well but I could keep trying to troubleshoot it. I do really like the sound of the conductive style.

[supple sky]

This is perfect! I watch this guy all the time and then buy stuff on Amazon to make something then fail LOL

[supple pollen]

Heh, something about "100W amplifer" with "extremely light sleeper" sounds like a possible issue

[dry pelican]

SparkFun has some surface transducers that you can hook up to an amplifier if you want to make your own

[supple sky]

Thank you, I think this is a good option too!

Is that all that is in a capacitive speaker?

[dry pelican]

capacitive?

[supple sky]

Sorry, I mean conductive, not capacitive.

[broken zenith]

Am I allowed to offer a one-time paid gig related to hardware design in this channel, or is the jobs board the place for that?

[rancid lagoon]

idk maybe

i don't see anything that says you can't but it also says that just because it isn't written down doesn't mean it's allowed so idk

[rancid lagoon]

i would go for the jobs board and if you get nothing than ask a moderator before posting it here

[distant raven]

The jobs board is the only place for paid work. Offering of or requesting paid work on the server is heavily discouraged

[rancid lagoon]

ok so don't post it here

that's why i said ask a moderator

[distant raven]

The reason for deferring people to the jobs board is because the posting a get vetted to ensure there isn’t a bad transaction. And it also helps protect this community from spam and members getting into a messy situation that is difficult for the moderators to handle.

[rancid lagoon]

makes sense

they probably should update the code of conduct with that

[distant raven]

It’s in there, I believe it falls under

“Discussion or promotion of activities or projects that intend or pose a risk of significant harm”

Though if you think it should be more clear, definitely make a suggestion in #help-with-community

[rancid lagoon]

It should be more clear because I didn’t see it

Done

[broken zenith]

Ok, thanks for letting me know. To the Jobs board I go!

[woven bluff]

is it OK to use 6.3V ceramic cap as bulk capacitor for 5V rail?

[supple pollen]

Should be fine, but some of the hi-K ones will lose some capacitance

[heavy jasper]

Are you planning on using it as the bulk capacitor for the output of a voltage regulator on the same board, or say the rail at the end of a long USB cord or set of wires to your power supply?

High-capacitance, low-ESR ceramic caps being hot-plugged into long inductive power supply cables can ring to ~2x the specified input voltage.

[dry pelican]

But you could mosly solve that with bypass caps placed near every component that needs them and a ground plane. Right?

[woven bluff]

it's the input bulk capacitor of SMPS

I'm trying to design a compact version of charge-boost board

is this reasonable?

unlike Adafruit charge boost, this one has an enable pin that works in all three conditions: 1.external powered 2.external powered, no battery 3.battery powered

[supple pollen]

As to the capacitor question, the PAM2401 data sheet recommends ceramic capacitors. The 47µF in the schematic should be sufficient, even if there's a loss of capacitance if you use a high-K unit (that much capacitance in a ceramic capacitor is likely going to be a high-K dielectric). I'm unsure why you have the AP2411 basically in parallel with the regulator, that seems like it could cause a short-circuit.

[woven bluff]

AP2411 is for situation when there is no battery

AP2411 has back-drive protection

[woven bluff]

is the output bulk cap 470uf an overkill?

[supple pollen]

Probably, but it depends somewhat on how much current you're drawing, your load, supply, and battery characteristics, and details like cable length, inductance, etc.

[woven bluff]

drawing 1-2A, load is another SMPS and a MCU

because there is a board space to place a 2917 tantalum

it could be replaced for other stuff, like output zener

all ceramic caps are x5r or x7r

[supple pollen]

I'm guessing you don't need a lot of capacitance if your load is another SMPS

[merry grail]

I'm looking at implementing wireless charging of LiPo batteries. Are there any common recommended ICs I should consider for my board?

[distant raven]

Well, last I looked there was only one Qi certified LiPo charger in stock

It was about a $10 chip though

[merry grail]

Do you happen to know the part number?

[distant raven]

Yeah, hold on

https://www.mouser.com/ProductDetail/Texas-Instruments/BQ51051BRHLR?qs=E2%2FxqS9xjzqw0w1tVVJkeQ%3D%3D&mgh=1&gclid=Cj0KCQiA4aacBhCUARIsAI55maGl2fcdguf6KkqgBBodMOT_Qe8JSIM4r3Zsnw34JKv7iTEcGMu5eMMaAguTEALw_wcB it’s cheaper than I remember

You will still need a transmitter but it’s probably better to get one that is already premade

[eternal fox]

The journey continues. Im currently wiring up my keyswitches in Kicad and wondering if theres a way of automatically get wiring within a certain distance of eachother. Like i have 70+ keys to wire, i want them to go according to a specific path and i want them as close to eachother as possible. When i try this i end up with minute variations in distance to each line and this is... annoying. Anyone with a tip on how to make this easier?

Also, a keyboard matrix, does it have to have the same amount of rows in each collumn or can you get around that somehow?

[naive gust]

http://www.keyboard-layout-editor.com/

this was insanely helpful when i built mine

paired with this

https://kbfirmware.com/

[eternal fox]

Thanks m8! Il remember that!

Is it stupid to do the pcb Footprint stuff first?

[naive gust]

I didnt do anything with a pcb when i built mine, all point to point. KBfirmware lets you put in how many columns/rows you want and itll generate wiring paths for you

so if you want to use the firmware generated by it I imagine you need to follow the wiring that it gives you

[eternal fox]

Btw, would this:

Be possible or would that via wreck the blue traces?

[limpid nest]

Via would wreck

[unreal flax]

Yep. That white circle there is a copper ring around the hole, so it would short against the blue traces.

[woven bluff]

just do this

[loud furnace]

Anyone got time for a dumb question about CANbus? It's in the "Why the heck would you try to do that" category.
I see there are lots of MCUs that support CANbus to some extent...including the RP2040 (https://github.com/KevinOConnor/can2040)
But... I don't have access to any CANbus Transceivers to use.
My understanding is that the transceiver just handles the putting transmits and receives onto the bus. There is usually a RX and TX for the MCU.

So my question is, what happens if you wired two MCUs together, TX->RX and RX ->TX

Would the communication still work (I understand the limitation that it's still only a 1-1, not a true bus)
This isn't for production, this is simply for testing communication so I can try out my code before I try to build hardware.

[eternal fox]

Thanks peeps! MVP's! ❤️

[hushed smelt]

Does anyone have a digikey part # for the STEMMA QT surface mount plug? I ordered some from Adafruit's site but those are the bigger STEMMA plugs and don't match the QT footprint. 😦

i've found 1528-4328-ND and 1568-PRT-16766-ND but unsure which is the right one for STEMMA QT. Also they're all out of stock. 😦

[eternal fox]

I did a while back, il see if i can find some.

No sorry, seems as if i've misplaced that link somewhere... Sorry m8!

[supple pollen]

I think that's a valid setup for testing

[loud furnace]

Thanks. I'll let you know if it does work or not.

[idle python]

hi guys

i made the usb 2.0 traces and theres like a 0,2200mm difference

will this work or no

[loud furnace]

you mean the JST-SH plugs with 1mm pitch? (like this cable - https://www.adafruit.com/product/5384)

[hushed smelt]

@loud furnace yes the PCB mountable plug for that one

[supple pollen]

It'll probably work, 220µm isn't a big difference. Those traces look a bit thick for USB impedance. Some of the newest modes are pickier, but they take more than two data lines, so I'm guessing you're not using those.

[loud furnace]

@hushed smelt https://www.digikey.ca/short/m30rvp7r is all I can find. If you needed the plug side, not the socket....I could find it. Sorry.

[hushed smelt]

found them https://www.adafruit.com/product/4208 adafruit does carry them. i bought the wrong ones.

STEMMA is JST-PH and STEMMA QT is JST-SH

[loud furnace]

@supple pollen Someone else over on the Dronecode Foundation server pointed me to this. https://community.st.com/s/question/0D53W000016m2LaSAI/onboard-communication-via-can-without-transceiver

[fervent lance]

are the pin 37 and pin 38 connected together? also vdd33 stands for vcc 3.3v? https://www.espressif.com/sites/default/files/documentation/esp32_hardware_design_guidelines_en.pdf under schematic checklist (point 2)

[loud furnace]

I would say no. First because there is no dot for the intersection showing the connection.
Second because 38 is GPIO19 and on the right it shows the connection labeled as that.

[unreal flax]

Yeah, agreed. The standard in schematics is to ignore 4-way wire crossings unless there's an intersection dot.

[dry pelican]

How would I design a spiral trace on a PCB for a pancake Tesla coil? Based on what I've seen, the traces should be very thin and close together to fit as many as possible into a certain space, but I'm not sure if it'll lead to arcing between traces if I design it wrong, or the PCB manufacturer cannot make boards that will work with my design.

[knotty tiger]

you'd have to at least know about the dielectric breakdown characteristics of the soldermask, probably. your board manufacturer might be able to tell you that, but you'd probably also have to simulate the actual peak electric field around your traces

[woven bluff]

How do you turn off SMPS regulator when VIN is high? Assuming battery connected.

[distant raven]

If you want the USB connector to work regardless of orientation, you’ll want to connect both DP together and both DM together

[onyx canopy]

I am a bit confused by JST connectors. From what I can see batteries usually have the electrically female ones and MCUs (e.g. https://www.adafruit.com/product/3405) have the electrically male ones. So far everything makes sense. I have a QTPy and soldered an electrically male JST lead to it.

Now, if I look at other products like https://www.adafruit.com/product/4755 or https://www.adafruit.com/product/4712 they have a pair of electrically male JST connectors and they leave me with a choice between two suboptimal solutions:

• use a cable with both end JST electrically female. It would work but in don’t have such cable and I’d rather avoid making cables longer if possible
• solder an electrically female JST to my QTPy instead of the male one I soldered already. That works great to connect to breakouts but then I cannot change my mind and connect the battery directly

Is there any best practice around this?

[sand mica]

That’s a thing I’ve pondered too. Currently I just have a collection of wires to flip gender on things. It seems to me that the trend is that boards have electrically male connectors, and batteries have electrically female connectors. I think it’s more of a “batteries have electrically female connectors”.

Like, at first I assumed that “power supply is female”, but that’s not always true, because a power source that charges a battery has to be male. So devices may use male or female connectors depending on their purpose, but batteries will always be electrically female. I assume that’s because a male connector is more easily shorted and shorting a battery is more catastrophic than other shorts.

Thus, many cables and adapters and gender changers are required when doing anything more complex than a single battery plugged into a single board.

[long wraith]

Generally batteries have the plug/female and things batteries plug into have the socket/male. The LiPo fuel gauge probably has socket/male for reduced BOM, and then the wires also are just plug/female to plug/female

[sand mica]

I remember as a kid my dad spending hours trying to explain why a socket is male and a plug is female, with me finding all the weird connectors that are different or where it’s not clear which one is the socket, hours on end. Foreshadowing for me coming out as non-binary trans a few decades later 🤣

[long wraith]

Lol. Yeah, connectors are just as much a spectrum as gender

[slow plover]

RP-SMA enters the chat

[woven bluff]

https://www.adafruit.com/product/2465

I have a problem with this, when battery voltage dropped below 3.4V, the boost output become 3v3

I have external supervisor that would disable the boost at 3.2V, this leads to system misbehave when battery voltage is between 3.2-3.4V

I suspect TPS61090RSAR switch off MOSFET when LBO (3.4V) is triggered

but this does not stop battery from draining

according to datasheet, the voltage comparator does nothing to the switch

and Input Voltage Range: 1.8 V to 5.5 V

so why does it fail at 3.4V?

[versed hamlet]

hello i wanna bit bang i2c for ds1307 manually with pushbuttons on my breadboard

would this setup work

i mean it pulls them low like epxected but for debouncing i mean is it fine

oh wait that led config is bad

[limpid nest]

How are you going to do 100kHz+ with your fingers?

[versed hamlet]

cuz

[spice turtle]

not to deter you, but the problem is, how will you generate ack/no ack signals? I2C is generally a complex form of serial coms

[versed hamlet]

datasheet doesnt have max time

[limpid nest]

Ah

[spice turtle]

also the clock speed can go down to 0 hz

https://www.analog.com/media/en/technical-documentation/product-selector-card/i2Cb.pdf

[versed hamlet]

i mean

wont i be able ot get the device to give ack signal

i tried doing it yesterday

i had bascially that setup but without the transistors

but i couldnt get ack

i mean it was prob cuz of the leds dropping the voltage ?

[spice turtle]

Doubt that much. You should put a separate resistor on the LEDs so it doesnt draw from the buss.

Are you just trying to learn how I2C works?

[versed hamlet]

ya

hoesntly i dotn even care about like writing or reading that much i just wanna see that ack bit lol

[versed hamlet]

at least for now cuz i couldnt get it to do it yesterday

oh yea but i didnt debounce

yesterday

i mean that has to be why then right?

[spice turtle]

Do you have a scope available?

[versed hamlet]

unfortunately not

when i start uni next semseter i will but yea not now

[spice turtle]

https://www.amazon.com/HiLetgo-Analyzer-Ferrite-Channel-Arduino/dp/B077LSG5P2/ref=sr_1_1?keywords=logic+analyzer&qid=1670118973&sprefix=logic+%2Caps%2C78&sr=8-1

get one of these

then you can use a micro

[versed hamlet]

yea i figured i would have to get a logic analyzer sooner or later

but i mean in theory at least

[versed hamlet]

this should work?

[spice turtle]

They are handy to keep on hand, or you can just throw caution into the wind lol

[versed hamlet]

i think this is better but im busy so ill try it tmr

[onyx canopy]

I think this is the best approach. I’ll leave the device with the male plug and get some wires to flip gender. While they arrive I should get unblocked with a combination of the wires I have and using the pins on the breakout boards. It’s not going to be pretty but I can live with that 😄

[edgy jungle]

Are there any good tutorials out there where I can learn how to add LoRa to a custom PCB? Without using a breakout module

[unreal flax]

The easiest approach would be to use like a HopeRF solder-down module, but if you really want to do it fully custom, you'd probably want to work from Semtech's datasheets.

[distant raven]

I've been trying to figure out was R_os means in this schematic... I can't find any reference to it in the datasheet

https://www.ti.com/lit/ds/symlink/bq51051b.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1670171077765&ref_url=https%253A%252F%252Fwww.mouser.cn%252F

only thing I can guess is a 0ohm but I don't want to make that assumption

turns out it is calculated with a tool that's export controlled lol...

and it's DOS only. WHY

found a reference schematic for a 500mA charge current, 20k resistor.

[supple pollen]

Wow, that's why I abandoned working on Nordic Semiconductor chips.

[distant raven]

nordic supports Mac

and DOS, and I think they have a linux tool now too

plus, you can build nordic SDK in linux too

[unreal flax]

One forum post suggest it controls the offset for the foreign-object detection circuit, so maybe that's where the "OS" comes from?

[distant raven]

If I scrolled further down the product page they had a 500mA charge current reference design which is what I'm doing

they list the R_os as 20k

It's interesting that Foreign Object Detection is an export controlled subject

[distant raven]

all this for wireless charging

lol

[limpid nest]

Nikola would weep tears of joy.

[distant raven]

placed and routed

weird, it's like there are pads missing

[unreal flax]

What kind of part is AC1 and AC2? That's an oddly asymmetric footprint.

[distant raven]

it's pads for the coil

[distant raven]

took a bit to get routed on 2 layers, but it's done.

hardest part was rearranging the display bits because I rotated the connector 90 degrees to get a better orientation in the case.

perhaps the most dense design i've done to date.

[unreal flax]

Yeah, that's quite impressive for 2 layers... 👍

[distant raven]

And the wild thing is, I could probably add a bit more before I’d have to switch to more layers

And using 20 of the RP2040 pins. Pretty hardware intensive.

[dry pelican]

You can get a super cheap one from Amazon, Adafruit, or Sparkfun (20-30 USD)

[unreal flax]

Yeah, those "24 MHz" clones are surprisingly useful for the price point. They're based around a unique Cypress part that's basically a USB logic analyzer in one chip.

[rancid lagoon]

nice routing

[pale harness]

Hey there, I've a TTGO Lora32 DevKit and checked it's schematics (https://github.com/LilyGO/TTGO-LORA32/blob/master/schematic1in6.pdf)
Seems they use a Common Mode Choke on the USB line, which should be a single part with 4 connections?(https://www.mouser.at/ProductDetail/TDK/ACM2012-201-2P-T002?qs=uxmvvYJjMItToju5t1EKiw%3D%3D)
But when i check the actual PCB, it looks like they use two parts here instead, are these ferrite beads? And do they have the same effect, or why they decide to use different parts than in the schematics?

[supple pollen]

That's a different part than in the schematic. If you look up the part number called out on the schematic (ACM2012-2P), it's a 4-pin package that handles both lines. I suspect the long solder joints are due to the smaller separate replacement parts.

The ACM2012 appears to be obsolete anyway, but if you wanted to use something like it in your design, the Bourns SRF2012-900YA appears to be equivalent and DigiKey shows them as active and in stock.

[pale harness]

i guess they use it because it's cheaper than the CMC's? Just wonder what parts these are they actually use, my assumption would have been ferrite beads, but i'd already suffer from finding out the right value to use there if i would also like to use the cheaper solution

[supple pollen]

It's going to be a very low value to avoid distorting the USB signal (they might just be 0Ω resistors)

[pale harness]

alright, many many thanks for your reply

the multimeter says 10 ohms

[supple pollen]

Looking at the ACM2012 data sheet, it's tricky: that part is available in varying versions, presenting a common mode impedance of 90-2000Ω at 100MHz. The DC resistance is specified at 0.19 - 2.5Ω so those parts may not be equivalent, and they're likely not ferrite beads unless your multimeter has issues with low resistance measurements (many do)

[pale harness]

yeh, the schematics are pretty unclear to me

And yeh, it's a very cheap multimeter ^^ says 0.4 Ohms when i just hold the probes together

would this circuit part even matter if the cable you use for the USB connection already has a Filter (the big ones around the cable) on it?

[supple pollen]

I wonder if the center components on the board are the parallel resistors and the larger outer parts (marked "B1") are something else. 🤷🏾

[pale harness]

yeh would make more sense

the resistors are 10 Ohm in the schematics

Can't measure the resistance of the outer parts tho

[supple pollen]

Oh, interesting, so perhaps the other components are some other thing. I'll often see low-value resistors (10-47Ω) in series with the USB data leads, but that's the first inductive component I've seen. The spike clippers are, of course, still a good idea.

[pale harness]

on another board, i broke one of the outer ones from the pcb when i tried to measure it ^^ But the board still works fine

maybe they are like here, these things? https://www.lcsc.com/product-detail/Diodes-ESD_LRC-LESD5D5-0CT1G_C383211.html

just 2 cents tho 😄

[dry pelican]

B1 are probably tvs diodes like that

[pale harness]

i've so much to learn 😄

[distant raven]

It’s the greatest part of being alive 😬

[pale harness]

indeed, but my brain won't get friends with that. It wants results without any effort 😢 ^^

[distant raven]

I have a saying: if you’re not learning, you’re probably dead 🙂

[long wraith]

What exactly does a logic analyzer do? Aside from the obvious of analyze logic

[distant raven]

It takes a signal analyzes it based on specific protocols and usually translates it to a readable waveform format

Like i2c for instance, if you’re analyzing an i2c signal against the i2c protocol, it will pull out start, stop, ack/nack, and user data from the signal

That way you are not guessing

[long wraith]

Ahh…

[urban lark]

Isnt that the job of a protocol analyser, but the logic analyser bit just records Samples of rising/falling edge things? I'm still learning, but there is a simple logic analyser on wokwi.com and it gives you a dump file to load in pulseview/gtkwave

[distant raven]

Eh, logic analyzers are more broad than protocol analyzers but the function of them is largely the same

For instance, a logic analyzer is great if I’m designing my own data transfer protocol

Per Google

Logic analyzers are more focused on test, protocol analyzers are for using in existing embedded systems for specific protocols

This explanation on EE blog is great https://www.eevblog.com/forum/beginners/whats-the-difference-between-logic-analyzer-vs-protocol-analyzer/

[pale harness]

The ESP32-WROOM-32E Module says i should pull up IO16. Any idea if it's really bad if i don't do that? Ordered some prototypes already before i noticed that note.

[distant raven]

Does the module have psram?

If no, it’s fine. If yes, you need it pulled up

[pale harness]

i think it embeds the ESP32-D0WDR2-V3, so yes i think

okay then my PCBs will need to be modified afterwards for testing 😝

or wait

i used the N16

the esp model naming confuses me ^^

and so many different ones ._.

here is the full datasheet tho https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32e_esp32-wroom-32ue_datasheet_en.pdf

[woven bluff]

anyone has powerboost 1000c? mine fails when battery voltage dropped below 3.4V

[long wraith]

Have you tried it with a different battery? if it's one with a protection circuit, the battery itself may not allow it to discharge under 3.4V

[woven bluff]

the board output dropped to 3V3 but can still supply at least 1A current.

I think the internal logic just stuck at switch-off rectifier-on, basically the battery current is just passing through the inductor and the rectifier.

[long wraith]

Hmm

[sick geyser]

What software can do with a logic analyser is where the magic really happens

[long wraith]

Ohhh, visualizing the data is awesome

[knotty tiger]

yes, good-quality protocol decoders are a must if you are using a logic analyzer

[crystal fjord]

Hi all, I am trying to build a prosthetic hand which can be controlled using an emg sensor.The emg sensor works with the help of an op-amp. For powering the whole circuit i am using lithium ion batteries along with a charging/ management circuit which can output 5v dc. For power the op-amp I need negative voltage at one terminal. How can I get negative voltage from input 5 vdc?

[worldly schooner]

You would need an inverting converter to generate your negative voltage from your input. LM79xx is a common choice for many of these applications, but unfortunately they would require a minimum of 7V input. I would try searching on Digi-Key for an appropriate DC-DC switching converter ic with negative output configuration?

[distant raven]

For a moment I thought you were suggesting using the 79xx to generate the negative voltage lol

I was like “that doesn’t seem right.” But then I reread what you wrote

[worldly schooner]

Yeah, if only 12vdc input was still as common as it once was.

I just don’t know the newer chips off the top of my head, haven’t really needed a negative supply for anything that’s not powered by an off the shelf ATX supply haha

[distant raven]

Yeah haha.. with so much being digital and being able to do most analog stuff by shifting waveforms up, it’s any wonder we have negative supplies these days

There’s still a big need for negative supplies in telecommunications though

[worldly schooner]

How wide a voltage range do you need out of your op-amp? If you only need 0-5V input and output you can connect the negative power terminal to ground.

[distant raven]

Or if you just need a negative reference and not a lot of current, a charge pump inverter would do the trick

[pure hinge]

hey folks, do you know how I can get custom cables? I'm not sure how to google for it, but I need 2/3 meters long cable with 3 cables in it

[distant raven]

DigiKey has a custom service. Not sure if you can get exactly what you want, but probably close.

https://www.digikey.com/en/resources/product-services#cables

[pure hinge]

nice, thanks! that's a good start 😄

the other option is get a cable that's close enough to what I need, and remove the additional innercables I guess 😄

[distant raven]

Depending on the connector, you might be able to find some premade cables on Aliexpress as wel

[flat vigil]

also https://dirtypcbs.com/store/cables

[pure hinge]

nice thank you!

[sick geyser]

Depending on what size cores your local electrical supplier might be an option too. and 2/3 meter you might even get away with an offcut

[twin hedge]

I'm making a small PC using the ESP32 that runs Linux. I'm using an ESP32-WROVER-E. I was wondering if I would be able to use the same components and schematic for the USB Type-C and USB/UART Bridge that the Feather ESP32 v2 does. Am I able to?

[worldly schooner]

Never knew you could run Linux on an ESP32, but I don’t see anything wrong with that.

[twin hedge]

Thanks. I'm trying to make sure I'm not gonna fry anything.

[worldly schooner]

Keep in mind there’s also some sort of dc dc converter between Vbus and whatever is powering the actual esp32.

[twin hedge]

Are you talking about the voltage regulator? I'm pretty sure it's used to get the 3.3V for the ESP32 from VBUS.

[distant raven]

uCLinux (microCLinux)

https://en.m.wikipedia.org/wiki/ΜClinux

I don’t see ESP32 listed as supported though

Looks like someone did it https://hackaday.com/2022/07/14/its-linux-on-an-esp32/

[frank onyx]

I'm using a motor driver (DRV8833) which has a 'fault' output pin that goes low open-drain when it is thermally shutdown. I'd like it to turn on an LED when this occurs so the user knows to stop trying to run the motors/knows why their motors have stopped. My first thought is to simply put it to the cathode of an LED, but does that mean that the driver needs to be capable of sinking the current from the LED? I'm not sure whether or not it's able to do that, or if it's just meant to be a signal for an MCU.

[limpid nest]

you could use a FET maybe? There are ones that go on when the gate is low

[woven bluff]

what current rating of a zener diode should be used for the output of a SMPS?

say the designed output current is 1A

[eternal fox]

Silly question incomming:

The luminecent Noodles (https://www.adafruit.com/product/5510), it says they need 3v but doesnt say anything about amps. Would a small battery be enough and do we know how much it draws assuming constant on?

[distant raven]

I’ve seen people light them with coin cells as they limit current draw to like 15mA

[eternal fox]

Wonderful! Was going to make a bracelet out of one, think it could be really cool 😄 Thanks m8!

[spark epoch]

Hi everyone! How do you call this type of powering where you use 2 different powering sources? I'm trying to search for info in Google to understand how it works.

[spice turtle]

I dont think thats a filter, It looks to be using a FET as a ideal diode, which combined with the other diode, makes this an OR circuit to select which power gets used to power the LDO. It basically lets you use either power supply and prevent back feeding.

https://electronics.stackexchange.com/questions/334947/equivalent-ideal-diode-circuit-analysis

Yea, take a look. Flip it on its side

[spark epoch]

Sorry, yes, the filtering circuit comes later, but I didn't show the full image. Thank you for the information. I'll take a look

[distant raven]

I believe you mean a NOR since of both the battery is connected and usb is connected, it will not conduct for the battery voltage effectively blocking it. OR would mean you would get both vbat and vusb at the same time if they were connected at the same time and that’s not what’s happened.

[bleak cosmos]

guys i need a small help

im working on the usb c, and im trying to connect it to ch340g

the problem is, there is no D- or D+

according to the datasheet...

[distant raven]

It appears it would be pins 5 and 6

[distant raven]

UD- and UD+

[bleak cosmos]

not the chip, on the usb c itself

[distant raven]

USB C has D+/D-

[bleak cosmos]

https://www.e-komponent.com/usb-type-c-receptacle-connector-24-position-through-hole

check this

[distant raven]

If it’s a usb 3.0 compliant receptacle, it’s A6/A7 B6/B7

[bleak cosmos]

no no, usb 2.0

[distant raven]

I use GCT receptacles and they definitely have D+/D-

[bleak cosmos]

i got the libriray from here

https://www.snapeda.com/parts/USB4085-GF-A/Global Connector Technology/view-part/?ref=global connector technology_in&t=usb c usb 2.0 receptacle&con_ref=None

[distant raven]

It would be DP1/2 and DN1/2

P for positive, N for negative

[bleak cosmos]

oh ok

thx

[distant raven]

You’re welcome

It can be confusing when it’s not consistent

Some us DM/DP

[bleak cosmos]

yah thats the thing

and when check on the web, it said that the dp is used for "display port"

[distant raven]

Yeah, it’s not always clear. I checked all kinds of data sheets when I first got started to understand nomenclature

[sweet pier]

Hi all, I got a bunch of ESP32-S2 boards back and suspecting that all the chips are faulty. I'm not seeing the serial port pop up in /dev/tty* in download mode as I have in the past with other boards. So I managed to probe the TX serial port, and see the output after download mode (holding [BOOT], clicking [RESET] and then releasing [BOOT]) and RESET - see the attached files. Any thoughts as to what the prob might be? One thing to note is that boards were fairly badly warped this time due to a copper density imbalance issue. Could that cause an issue like this? If it was, I'd kinda expect the chip to not work at all.

[sweet pier]

Can this cause a boot failure?!

[distant raven]

Wow, that’s really warped

Who did you get these through?

[sweet pier]

PCBway

[distant raven]

Hmm.. I’d verify that your schematic didn’t have any glaring errors that would cause it to not work and then reach out to PCBWay, I’m sure they’d work with you on replacements

[sweet pier]

PCBway refused due to the copper density issue 😒 The design looks ok compared to a previous version, but checking again. Any thoughts on those boot issues? E (78) boot_comm: mismatch chip ID, expected 2, found 0 is strange.

[rancid lagoon]

Fake/broken chip?

[sweet pier]

Sourced by PCBway from China, guess it could be fake 😖

[outer adder]

One question,I have some sensors in chain and I am using a LTC4311 I2C Extender to reach distances like 2-3m,but the bus should also be hot swap so I bought a Adafruit TCA4307 Hot-Swap I2C Buffer.Will this work?And is there any importance is I place befeore the Buffer or after the extender.So can the components be placed in this order Raspberry--Buffer--Extender--Sensor1--Sensor2--Sensor 3.

[hushed smelt]

a lot of my pcb's from JLPCB are slightly warped, nothing remotely close to that though. probably part of the FR4 manufacturing from rollers?

if they weren't perfectly flat they wouldn't be able to route and drill correctly. had to happen after that like baking on the mask and silkscreen.

[woven bluff]

is this footprint acceptable for castellated holes?

this is the castellated holes (upper row) of the SMD mounted board

[distant raven]

Yeah, just make sure you select castellated holes on the PCB fab options

[twin hedge]

Does anyone know where I can find a USB Type-C Receptacle part that has a similar symbol in KiCad?

[twin hedge]

My existing receptacle has DP1, DP2, DN1, and DN2 pins, which confuses me because I'm using the same USB/UART Bridge in the image and it only accepts one D+ and D-.

[unreal flax]

USB-C has duplicate pins for the same signals so the plugs work in both orientations. You'd just connect them both together on the board, typically.

Sometimes the symbol would do that internally, too.

[twin hedge]

Connect them with something like a junction?

[unreal flax]

Yep, just wire them together I mean.

[twin hedge]

Thanks.

Oh. I need to know something else. What 3.3V voltage regulator is good for an ESP32?

[unreal flax]

Lots, potentially. Do you want a switching or a linear regulator? From what input voltage? As a chip or a module?

[twin hedge]

Since I'm using USB Type-C, I believe the input voltage is 5V. I need an output of 3.3V @ 1A. I'm not sure if it needs to be a chip or module. Would a switching or linear regulator be better?

[unreal flax]

Linear is simpler / cheaper / cleaner, but it's less power efficient, as it just throws away the extra 1.7V as heat, which can also require a heatsink, depending on the chip package and average current draw. Switching is more efficient but electrically noisier and takes more components like inductors.

[twin hedge]

Would something like a LD1117AS33TR work? . I believe I can replace the 100nf capacitor in the diagram with a 0.1 µF capacitor.

[unreal flax]

Yes, 100nF is the same as 0.1uF, since there's 1000 nanos to a micro.

And yes, that's a popular linear regulator, so it should work fine.

[quick dirge]

anyone have reccomendations for small dev boards that can handle neopixels and 5v logic without a shifter? (pref with usb C and as small as possible)

I've been looking at items with the atmega32u4 mostly

but the atmega 3248p could also work

[knotty tiger]

what languages are you planning to program in?

also, NeoPixels are mostly OK with 3.3V logic if you give them 3.3V power (maybe with some power distribution challenges for longer strands, etc)

[distant raven]

depending on the variant of neopixel too. WS2812B not so great, but SK6812 do much better over distances.

I at least haven't seen issues up to 1m in length

[quick dirge]

Arduino

[quick dirge]

It's been a hassle with my Xiao rp2040 . Only lights the first pixel. Otherwise the signal doesn't carry well enough

[supple pollen]

That's odd, each one regenerates the signal so if the first one works, the others should (from a signal level standpoint)

[scarlet jay]

Hey, Gs I have a circuit ready but I need to make a small board put into the product out of it. tell me how! 🙌

[distant raven]

I would suggest giving some details about what you are trying to make, what kind of circuit you have, and what tools you plan to use if you have picked that already.

[scarlet jay]

I have a breadboard ready 🙂

[distant raven]

okay, if it's breadboarded, one of the easier things to do is get a Permaproto from Adafruit or any other protoboard and solder it in with solder and a soldering iron.

I suggest adafruit because their permaproto are set up just like bread boards so it is much easier to move it over to a permanent installation.

[scarlet jay]

okay and if I have that ready, how do I make it so small that it can fit into 5x2 case 🙂

cm*

[distant raven]

so, if you want to make a custom printed circuitboard you will need to get an ECAD program.

there are free web browser based ones like EasyEDA which has lots of parts already on there and it imports directly into JLCPCB for ordering and fabrication.

if you want a have a more full featured, but slightly more difficult approach, you can use tools like KiCAD

[scarlet jay]

okay and where can I fabricate it at? 🙂

because I don't know how those places are called 🙂

[distant raven]

JLCPCB, OshPark, PCBWay, DirtyPCB

lots of great options once you've designed your PCB

[scarlet jay]

okay G, thanks a lot, lemme try to hang on this 🙂

[quick dirge]

There are so many lil things that have been documented and noted issues with Xiaos and neopixels in particular so I'm just tryna avoid that all together now

[unique patio]

Our ItsyBitsy boards have a a built-in 5V level shifter on pin 5: many microcontrollers available: https://www.adafruit.com/?q=itsy&sort=BestMatch

[quick dirge]

cool! by chance are there any with type C ports?

[unique patio]

they were designed before USB C was common. There are tiny USB C to micro B adapters, but we only sell ones that are the other way round. Also this board is in the works, but not out yet: https://blog.adafruit.com/2022/10/27/adafruit-top-secret-october-26-2022-adafruit-adafruittopsecret-scorpio-adafruit/

[quick dirge]

oh! very cool, thank you

[quick dirge]

do you have any estimate on cost for this? because if its within the budget, it could be perfect

[unique patio]

the scorpio? No, no estimate, but the extra components are not that much. There are breakouts that are level shifters, but maybe that would make something too thick for your purpose. Is it a single strand?

[quick dirge]

its a single chain on my own pcb.
I was using a xiao rp2040 before hand but it had a lot of issues level shifting and only ever lit up the first neopixel

[unique patio]

I didn't look back, did someone suggest the trick of a single extra neopixel at the front of the string? Power it with 4.3V through a regular 0.7v drop diode. Then you can feed it with 3.3v logic. It will regenerate a 4.3V output signal which you can then pass on to the 5V string

[quick dirge]

no, I had read about that though while searching the web, the first pixel basically acts as a sacrifical one, right?

[unique patio]

yes, since it will be very slightly dimmer, which may or may not matter for your use case

requires extra wiring which may be tricky if this whole thing has to be flexible ot something

[quick dirge]

its a board for a custom arcade controller, so it doesn't need to be flexible thankfully,
as long as the dimming isn't too noticeable it could work

I can wire it up and later tonight or this week if I have any of those lying around, I'll give it a go, thank you!

[woven bluff]

will the NMOS turn on when the EN pin input is floating?

[unique patio]

I don't know if you have room, but we have this: https://www.adafruit.com/product/4056

if you wanted to use the Itsy's and required USB-C

assumiong the idea is to have a jack sticking out somewhere

[quick dirge]

ah! unfortunately the board is tryna be kept as thin as possible, so that wouldn't work

its currently at about 1/2"

[unique patio]

so plenty of room but just thin

[quick dirge]

yup!

[unique patio]

https://www.adafruit.com/product/1875 but maybe unnecessary given the other solutions

you don't need bidrectional but no big deal

plenty of single chip level shifters too, in DIP or other form

https://www.adafruit.com/product/3877

[quick dirge]

i was reading about this, apparently its not strong enough for leds or long cables

im not sure if my board fits into that

[unique patio]

https://learn.adafruit.com/adafruit-neopixel-uberguide/logic-level

how long is long

a long string should make no difference: it's the distance to the first pixel

[quick dirge]

of the first pixel is maybe an inch or two away

[unique patio]

that's no issue at all then

but just something like that DIP IC is very easy too

[quick dirge]

yeah, I was looking at that, unforunately it was too thick in that package, and it seems the others are a bit annoying to source for pre assembly atm

[unique patio]

since the logic level is reconstituted at each neopixel, only the first makes a diff

[quick dirge]

I see.

I'll try that logic shifter then and see if it works, for some reason the last shifter I chose just wouldn't function right

[unique patio]

also we have this: normally it stacks but you could mount side by side: https://www.adafruit.com/product/5645

[quick dirge]

oh! that might be perfect

this might actually save me here, thank you!

[unique patio]

yw -- order now, only 5 in stock! 🙂

[rancid lagoon]

I can only dream of my projects looking that good

[quick dirge]

haha I work as an illustrator so I'm a stickler for things looking nice, unfortunately that sometimes means I spend time on that for prototypes

[rancid lagoon]

I like my projects looking neat but simple so keep stuff aligned and all the same size (0603)

On my latest one i even added a small joke to the silkscreen

[quick dirge]

oh i filled my silks with dumb images LOL

this is just on the back

where no one will likely see it

[quick dirge]

can they be directly stacked without pinheaders? or are they likely to short on the bottom side pads of the xiao?

[rancid lagoon]

That copyright text was a joke i added (it’s just for me so it’s not for a commercial product)

[quick dirge]

hah

[long wraith]

If it’s on there it’s legal

(Not actual legal advice)

[rancid lagoon]

Probably should have gone with llc instead of inc now that i think about it

[long wraith]

Lol

[quick dirge]

nlc

no liability corporation

[rancid lagoon]

That means i can sue anyone who copies my design from here and sells it

[long wraith]

NEC: non-existent corporation

[long wraith]

https://tenor.com/view/sue-lawyer-case-cat-hat-gif-9688693

[rancid lagoon]

Limited liability not no liability

[quick dirge]

I know, I was making a joke.

[rancid lagoon]

That would be perfect but it’s already been panelized so i can’t change it

[long wraith]

RIP

[long wraith]

I have seen this gremlin elsewhere but do not know the name

[quick dirge]

Neco Arc

[rancid lagoon]

https://tenor.com/view/sue-lawyer-case-cat-hat-gif-9688693 i got the link

[quick dirge]

I play a lot of fighting games, and she has been with me ever since I encountered Melty Blood loll

[long wraith]

Hehehehe

[rancid lagoon]

It seems like this is the channel for tangents

[long wraith]

Did it not embed for you?

[rancid lagoon]

It did i just copied the link

[long wraith]

Oh yeah we did tangent didn’t we

[long wraith]

Oh, lol. I love that GIF

[quick dirge]

i gotta get back to work anywho, thesis time here we go

[long wraith]

I gotta go too, need to go grab a new soldering iron… ttyl peeps

[rancid lagoon]

A few weeks ago there was an almost war about wether the windows 10 or 11 menus were better

(I was the person fighting for win 11)

Cya

[unique patio]

you have to stack it on top because of the thickness of the connector. But i think there is nothing conductive on the bottom?

https://learn.adafruit.com/adafruit-neopixel-driver-bff

[quick dirge]

ah, I'm most likely going to desolder that connector anyway for height clearance, but I guess the smd devices would get in the way due to its orientation from what I'm understanding

[unique patio]

yes, it can't be absolutely flat, so that's why I suggested side by sdie

[quick dirge]

alright! i can definitely fit that on the board!

[unique patio]

if the strip is off somewhere else, then the connector might be useful for assembly/disassembly

[quick dirge]

it's all on the back of the board as seen here (was testing for dead leds, so those are the ones not lighting)

[unique patio]

i see.

of course we have QT Py RP2040 is is the same as the Seeed more or less, though the Seeed may have some price advantage

[quick dirge]

yeah, thats the main reason I went for the xiao, I'm developing these on a very tight budget

ideally, if I ever produce these in anything more than hand soldered stuff, I'd likely just integrate an rp2040,atmega32u4, or attiny85 on the board itself

but chip shortages have made sourcing the latter 2 very difficult

[supple pollen]

DotStars sidestep a lot of such issues

[quick dirge]

dotstars?

[distant raven]

APA102 or something like that

[quick dirge]

oh, i never knew those were a thing!

can they run on on the neopixel library?

[distant raven]

They use the dotstar library

Which Adafruit supplies drivers for in both Arduino and circuitpython

https://m.aliexpress.us/item/2251832775941692.html

These are a larger version of what is usually the APA102

https://m.aliexpress.us/item/2251832665262906.html

These are the typical size I see uses

[quick dirge]

hmm.. maybe

would require rre-wiring the board though

[quick dirge]

quickly did a wire up, does every pin need to be used? or as long as the 2 voltages, gnd, and the data pin does it work alright?

[supple pollen]

Every pin of what?

[unique patio]

best to look at the schematic: https://learn.adafruit.com/assets/116774 (from https://learn.adafruit.com/adafruit-neopixel-driver-bff/downloads)

A3 is the default level-shifted pin: https://learn.adafruit.com/adafruit-neopixel-driver-bff/pinouts. You can cut its jumper and solder one of the other ones. So no, you don't need to connect the other pins at all. Just connect power, ground, and A3, or whatever other pin you are using. Obviously A3 would be easiest.

I note that the picture says it could be soldered back to back (not stacked). You mentioned that before, but you have room to not do that

[quick dirge]

I'd have to measure with some calipers and see, I have only about a milimeter of more clearance if I where to stack them

but then I'd also have to manually wire out the signal pin

[unique patio]

given that you have so much board space, doing them separated seems easier

[quick dirge]

yeah, definitely!

I'll clean them up once I get the board and test how it does by just wiring manually initally

thanks again!

[shell sapphire]

I'm wondering if the following is possible:
Turn 20 LEDs (RGB fading) on and off for a random period of time using purely ICs. I can do 1 easily with a 555 timer but having issues trying to work out how to do 20 of them, as 20x 555 with associated differing caps and resistors would be madness; doable but madness 😄

I have done it easily with Arduino, etc but want to try it in pure hardware

[supple pollen]

It's absolutely possible. There are a lot of possible approaches. You could use logic gates to combine outputs to get new outputs, look into tapped shift registers to generate pseudo-random numbers on the fly, or go with a more analog approach of several oscillators with their beat frequencies in various combinations to drive LEDs, or all sorts of things I haven't thought of.

[shell sapphire]

ooh LFSR - nice idea

aha https://www.interestingelectronics.com/old/henrys_interesting_electronics/xmas_lfsr/xmas_lfsr.html

@supple pollen you are a star

[supple pollen]

Amusingly, I picked up this interesting homemade light piece on eBay a while back (the listing claimed it was "musical", but that is not the case). It had 4 strings of series connected C6 bulbs run off a pair of electromechanical flashers. One of the flashers had stopped working. I ended up replacing the flashers with a 4-channel electronic blinker (built out of an older version of a computer controlled dimmer project I had lying around) to get it working again.

[shell sapphire]

Week back I saw and now want a "The Lyte" https://www.youtube.com/watch?v=OR5yhgupt0g

That light piece reminds of the light boxes I used to have when DJing back in the day

The guy who built my lights made something similar to this https://www.instructables.com/555-Timer-Metronome-Audio-Visual/ so that I could control the main box with the BPM. A button and a potentiometer - button to go off, release on a beat - adjust accordingly. It took someone else to do it as doing the lights as well as mixing was beyond my skills of tracking multiple BPMs at the same time 😄

[long wraith]

I too want THE LYTE. I also now want that particular 555 metronome, lol… looks like a proper time traveler’s device with the really old tin, kinda old plastic that I think is part of a smoke detector, and shiny new fittings and switch and LEDs

[quick dirge]

so I was reviewing the schematic for the logic level shifter used on the BFF. so I would only need the 5v and not 3v3, because it knows that voltage just from the data line? or should I keep 3v3 connected to both

[supple pollen]

I don't think it needs the 3V supply to be connected

[rancid lagoon]

What if you flipped the footprint but kept it on the top layer and put a cutout in the pcb for it?

So that the components are “in” the pcb so after you remove the jst it’s both protected more and shorter

[quick dirge]

thatd mean I'd have to cut out more acrylic from the top panels. and I dont really want to do that lol

[rancid lagoon]

Ok it was just a thought

[quick dirge]

i get your thought process! on its own its a clever idea

it just doesn't happen to fit my current use case is all

but if that changes I'll be sure to implement it :)

[rancid lagoon]

I was just zoning out thinking about idk when i thought of it then i hopped on discord

[dry pelican]

I'm back to debugging this single mosfet tesla coil driver. I got it to "work" no coil attached with the signal generator on my scope at 1.2MHz attached to the feedback input. However, when operating like that, the circuit draws 130mA switching the mosfet on and off, and the gate resistor gets hot quickly. Any advice on gate resistors? I'm using 4.7 ohms, but I also have a 1/2W 1 ohm resistor on hand.

There are a lot of bad connections on the board because solder does not flow well into pads that are connected to the ground plane. Any advice on that as well?

My next step would be hooking a coil, a fan, and a heatsink up to the board.

[long wraith]

You can add a bit of flux on the pads to help solder flow

If you're using rosin core solder and it isn't flowing well, it might be old. If it's not rosin core, you definitely want to use flux

[dry pelican]

That could work, but it's also really hard to desolder components (the ones that are attached to the ground plane are nearly impossible) even with the engineer solder sucker.

So I think it's a heat issue, but adding more heat could break components

[long wraith]

Rosin-filled desoldering braid will do a much better job than a sucker

[dry pelican]

What if there's solder in the vias?

[long wraith]

You might need to poke a wire in to help coax it out, but the desoldering wick/braid will do a good job of sucking most of it up

[dry pelican]

Any advice on the gate drive resistor heating up?

[long wraith]

Unfortunately I can't help you there

[supple pollen]

Assuming the resistor that's getting hot is the gate resistor, I can think of two main possibilities. One is that everything is basically working, and the current to charge and discharge the gate capacitance flowing through the resistor is causing the heating. If that's the case, you may need to adjust the frequency, resistor value, or resistor wattage, or swap in a MOSFET with a lower gate charge. However, some other problems (like damaged MOSFET gate insulation) can also cause resistor heating.

[dry pelican]

Possibility 1 is almost certainly correct. The resistor is just heating up because of the current flowing back and forth through it. I just need to figure out what the resistance of the resistor should be to switch the mosfet fast and reduce ringing and power loss. I came up with an equation that should be able to predict the power dissipated in the resistor.

X1 is the gate capacitance’s impedance. Since it acts like a resistor divider (I think (I’m not an EE)), I can calculate the voltage drop across R1 (the gate resistor), and get the power lost across it.

X1 is the impedance of a 2nF capacitor at 1.205MHz

Actually the impedance is 31.4473 ohms. I thought the gate capacitance was 2nF. It’s actually 4.2nF for the IRFP460

And plugging 4.7 ohms for the gate resistor in gives a little over 0.5W of power dissipated, which makes more sense with the heat I felt on the resistor.

1 ohm should be much better

But then how do I calculate how much the resistor will damp the ringing? (Although that’s hard because I don’t know the inductance)

1 ohm gives 0.13W of dissipated power

[supple pollen]

Ordinary 10 mil PCB traces (if not over a ground plane) are a few nanohenries per inch. I doubt ringing is likely to be much of a problem unless you have the driver well separated from the MOSFET

You could try a ferrite bead to help damp ringing if it's an issue

Eyeing your board pic, it looks like a fairly wide trace, so probably pretty low inductance. There appears to be a chonky diode too which should clamp ringing if it's a fast-enough diode (or make the resistor hot if the diode is connected wrongly)

[knotty tiger]

can you show your board layout in detail? you might need thermals for your component pads on the ground plane if you don't already have them

[dry pelican]

Thermals?

[dry pelican]

Chonky diode is a 1.5KE12CA (bidirectional TVS) to prevent the mosfet gate or driver from going boom

[knotty tiger]

short for thermal relief. short spokes around a component ground pad connecting it to a ground plane, to make it easier to solder and rework. the spokes conduct enough current for the circuit, but add enough thermal resistance to help with (de)soldering

[dry pelican]

Yes. Those are on the PCB. They make it possible to solder to, but the joints are not the best and they’re almost impossible to desolder

[knotty tiger]

ah. i can't tell easily from the photo. i did see a few that might have thermals, but their spokes look wide and short, so might not help as much as you would like

[dry pelican]

That might be true. I’ll fix that on my next boards.

[dry pelican]

Even if it’s 20nH inductance for that trace, the resonant frequency would be over 10x the operating frequency of the driver. The trace is also right next to a plane (connected to the mosfet drain), and there’s a ground plane underneath it. With that low of an inductance, a small resistor should be able to damp if well.

[pure gorge]

Is this chip able to take regular binary instructions from lets say an Arduino or RP2040? I'm asking because I can't tell if it uses some proprietary hard to understand protocol that I'm just not seeing. https://en.wikipedia.org/wiki/Ricoh_2A03

Seems like it uses MOS 6502 instructions, but I don't know how it recieves those instructions

[unreal flax]

It looks like the pins include an address and data bus, so it would be reading its own instructions from an external RAM / ROM chip.

https://www.nesdev.org/2A03 technical reference.txt

[pure gorge]

I know almost nothing about CPU instructions, so this may not be a suitable thing to learn yet. But I do have some raw NES sound files that most likely contain the instructions needed

I could possibly emulate a RAM/ROM chip right?

[unreal flax]

It would be straightforward to do with an FPGA. Less obvious with a microcontroller, but probably still possible with a Pico since it has the advantage of clock speed and the PIO feature.

[pure gorge]

Ok, I haven't gotten into FPGA stuff yet but I do know some things about programming the RP2040. I'm assuming CircuitPython won't really work for this but I can probably figure out C or C++ on it since I already know how to program in them.

[unreal flax]

Yeah, this probably wouldn't be CircuitPython. You probably already know, but I would assume that there are NES emulators out there which can already deal with this chip's sound generation.

[pure gorge]

Yeah, I just wanted to make a microcontroller capable of playing NSF files using a real NES sound chip but it might require an actual NES CPU

[unreal flax]

One intermediate design might use an external RAM chip which the MCU programs and then lets the sound chip access directly.

[scarlet jay]

Hey guys, how do you put a Bluetooth into a board as simple as this one?

[lean oriole]

Hello, so I'm trying to build and instrumentation amplifier with an lm324 and on the datasheet of the ina114 https://www.ti.com/lit/ds/symlink/ina114.pdf it shows six 25k resistors but on guides such as this https://youtu.be/bcq9NA4FgFk?t=363 on how to make it online, they use six 10k resistors, any idea why they do that, like are there any performance differences or something?

[supple pollen]

That chip is the CPU, so you don't really need a second CPU.

[supple pollen]

The important thing is that the resistors are matched, which is why some chips include them on the chip itself. The actual value determines the impedance of the circuitry, higher impedances are easier to drive but more susceptible to noise, so (as in all engineering), it's a tradeoff.

[lean oriole]

Oh I see, so doing more research this is what I've gathered, hope it's correct
Say I use six 2k resistors and then use a 20 ohm resistor, is it correct that it would give a gain of about 200 while using about 2.475 mv?
The formula of 5v/2.020 to get 2.475 right?
Also on this https://electronics.stackexchange.com/questions/300565/side-effects-of-using-large-resistances

Smaller resistors in feedback systems, e.g. with inverting amplifiers using op-amps, may cause errors on the incoming signal if the incoming signal is relatively weak.
The input is a four load cell wheatstone bridge so I'd assume that counts as relatively weak?
Don't want to use the hx711 because I want a faster sample rate using the adc on an arduino
The current setup that I got working for it is a single lm324 but the output fluctuates by like around a hundred or two and drifts after maybe a minute or two?
So hoping this helps to fix that
Not sure, do you know what he means by errors, is it basically just random spikes of values or something?
If so, then should I just use six 24k resistors and a single 240 ohm one?

[lean oriole]

Oh also not sure if this is correct too but on page seven of the lm324 datasheet https://www.ti.com/lit/ds/snosc16d/snosc16d.pdf it says

Output current - min 10, typ, 20, with no max
If the 2.475 ma calculation is correct, would it use just about 10 ma since I'm using all four outputs or is that incorrect?

[twin hedge]

How can I make an auto-reset like this without outputting to GPIO0? I'm using a CP2102N and the USB/UART Bridge that outputs the DTR and RTS signals.

[knotty tiger]

why do you have n-MOSFET symbols labeled as "DUAL NPN"?

[broken zenith]

I'm about to push the updated sources of my E-Fidget PCB, but I want to pick a good license first. I want something permissive, but not so permissive that someone can run off with my design, close source it, and sell it as their own. I took a quick glance at https://choosealicense.com and the CERN-OHL-W looks good, but I'm curious what y'all think about this. Thanks!

[pure gorge]

Yeah sorry i misread the wikipedia page on the chip

[supple pollen]

I'm not following what you're doing here, like where is this 20 ohm resistor, and what you mean by "using" 2.475mV?

[uneven cloak]

Take a look at Arduino, then look at all the clones out there and then think about how safe your design will be once you place it on the net. without a world wide patent and a million dollar company to back it I would just pick one and hope.

[fervent lance]

as I did understood outside of a patent (around 20k for the wipo global one), there is not much, there are some open hardware licensing but they are not that much protective, besides they are a bit of a comunity/industry based strech of the copyright system, as I saw there are like no real cases to take as example.

you might want to try to obscure it, but if it has market it will definitely get cloned.

some have lawmakers friends, others are so big that they don't care, others might sell it as long as they can't, then find a second dumbbell to use to continue selling. so it's more about mitigating