help-with-hw-design

[fast tundra]

Oh that's you! 😎

[tough matrix]

yep, decided to make my twitter handle less personal

[fast tundra]

Here's another useful app note for tcc stuff https://www.google.com/url?sa=t&source=web&rct=j&url=http://ww1.microchip.com/downloads/en/AppNotes/SAMDE5x-Advanced-Features-of-the-TCC-Module-DS00002743A.pdf&ved=2ahUKEwjg2-2Ay8LtAhVjxFkKHcyFDJ8QFjAAegQIARAB&usg=AOvVaw2p0gVfva4b-GDgOc7FAkss

[tough matrix]

bookmarking

[fast tundra]

But I love your project, btw.

I love seeing more open source stuff in robotics, especially aimed at education.

[tough matrix]

I have been coaching First Tech Challenge team for like 10 years

[fast tundra]

It's so frustrating how FIRST's hardware and software platforms are closed source.

[tough matrix]

yeah.. and it is not cheap either

REV cotnrol hub costs $300

[fast tundra]

Oh god it's SO expensive.

[tough matrix]

were you part of FRC/FTC?

[fast tundra]

Between the power distribution module and the roborio that's like $1,500 of a teams budget. And you really need two so you have a backup.

[tough matrix]

We are community team meeting in a basement
so FRC is not an option

[fast tundra]

Nice.

[tough matrix]

FTC is more manageable, but still not cheap

[fast tundra]

Honestly all the better.

Yeah.

[misty escarp]

seems like a good space for an open source community to disrupt

i don't love the term disrupt but it's appropriate here

[fast tundra]

😬

Eh. FIRST as an org is pretty entrenched.

[tough matrix]

somehow, there are hundreds of "robotic car using arduino" projects which are really basic
and then there are reasonably advanced things such as FRC/FTC
and very little in between

[fast tundra]

Yeah

I can't remember the name of it but I came across some open source robotics stuff in the UK. They had a really well designed power module that implemented safety features similar to FRC- stuff like requiring the CPU to communicate or it would shut down, overcurrent protection, etc.

[tough matrix]

Pololu makes nice little robots, very neat for educational purposes - I used it in a couple of summer camps - but software is lacking

[fast tundra]

It could cut power to motors if it wasn't receiving a signal from the controller.

[tough matrix]

Need to look at it... haven't seen this one

[fast tundra]

But yeah. I think a robotic safety platform like that would be a killer thing to have in OSH.

Like.. use whatever brain you want, but use this module for power, monitoring, and such.

[tough matrix]

our project is open source
but it is for small robots - like the one on my avatar

[elder peak]

I mean, take a step back and probably a bunch of stuff delivered as OSH so that you won't roll it yourself all to do with safety.

[fast tundra]

Yup

[elder peak]

Like, sure, a 3D printer can be considered a robot.

[tough matrix]

🙂

[fast tundra]

If I weren't building synthesizers I'd probably be doing robotics stuff. :)

[tough matrix]

there is a lot of open source work in quadcopters

[fast tundra]

But I can scratch that itch with mentoring for FIRST.

[elder peak]

I'm kinda weird in that, other than not having space for a CNC but wanting to build one anyways, I'm not super-interested in robotics-robitcs.

[tough matrix]

each of us is weird ... in our own way

@fast tundra are you already mentoring, or is it for the future?

[elder peak]

I lost it sometime between the heyday of BEAM electronics and partway through when Boston Dynamics started doing stuff and I watched a Tested.com video on the robotic dog and halfway through I started yelling at the screen.

[fast tundra]

I was mentoring in Seattle (I had for 4 years) but I moved and I haven't yet found a new team. And that'll be hard until schools actually open back up.

[elder peak]

But, like, harm reduction. A lot of folks are like "DON'T TOUCH THAT I WON'T TELL YOU HOW TO DO IT" and then you end up with actually dangerous hardware being made because people don't listen to you when you say don't do it.

[tough matrix]

@elder peak when you say "people don't listen" - you are talkign about developers or users?

[elder peak]

Hobbyists, mostly.

A lot of stuff that requires at least a bit of safety engineering is stuff that people want to do, and the traditional attitude is to not describe how to do it at all.

Thus, a hobbyist will try to reverse engineer how to construct said item and probably will find some sort of resource on the subject.

[tough matrix]

yeah
seen that, indeed

[elder peak]

And, frequently, the best resource is something from the days when home chemistry kits included radioisotopes.

Kids! Let's make rocket candy in the same pot your mom uses to make porridge!

[distant raven]

@fast tundra I’ve really been exploring the depths of the SAME/D data sheets. So much to take on but so good

[fast tundra]

It's a really good family of chips

[distant raven]

Yeah, the ESP32-S2 data sheet and information is spread across three data sheets

Not as helpful as the atmel/microchip MCUs

[fast tundra]

Heh. Idk. I find myself digging through application notes to find some information.

Figuring out some of the deep secrets of the ADC and also getting i2c to work required some app note archeology.

[tough matrix]

for me, i2c worked out of the box using arduino default Wire library

[fast tundra]

But anything is better than the stm documentation 😅😅

Oh, yeah, I'm just not using Arduino for stuff.

[tough matrix]

yes, their wire library is not great, but i am too lazy... what do you use for programming samd chips? Atmel studio?

[fast tundra]

Bare metal. gcc-arm and the CMSIS headers.

[distant raven]

I’ll be there soon

My job I start in January is an embedded software job

[fast tundra]

I think a mix of Arduino and register twiddling through CMSIS stuff is a good approach for most projects.

[distant raven]

So lots of bare metal programming

[fast tundra]

Nice! Can you share what you'll be working on?

[distant raven]

ummm, vague and obscure details lol

[fast tundra]

Hehe. Well, I hope it goes well!

[distant raven]

Same! It’s supposed to be working on cutting edge communications systems

So I’m excited for the challenges it will bring

[fast tundra]

Neat!

I often think about switching from my current job into something working with hardware, but 🤷‍♀️

[distant raven]

I figured I don’t want to get too deep into hardware for my main money maker so I can enjoy my hobby business 😃

[tough matrix]

a little too late for me to switch jobs...

[silk lark]

it's never too late

[ember laurel]

What are you guys using for serial numbering your boards?

[silk lark]

what do you mean?

[ember laurel]

serial numbering each board for shipping to customers

To maintain records, quality tracking and so on

[silk lark]

I never needed to do that, but if I did, I would probably get one of those label printers and print stickers with the numbers and/or bar codes

[ember laurel]

I just ordered a bunch of Avery weatherproof labels

I don't want any stickers that fall off due to crap glue

but I also don't think they need to be rework resistant

my plan is to print the labels with a QR code and stick them onto the PCB's.

Then when uploading the firmware, the serial will be embedded into the firmware by a software I'll write

that will use either a handheld scanner or a webcam, to synchronize the uploaded firmware serial with the board

(the same software will perform self test and some manual QC)

[vapid grove]

Sounds cool!

And complicated

[onyx sail]

Hey, We have to make a safe for a school project. We can use one shift register, one bcd decoder and one arduino to control 3-7segments display an rotary encoder and some leds and a button. Anyone who can explain me how to connect 3-7segment displays to one bcd decoder and one shift register? Ofcourse you can use resistors, transistors and more to create a solution for this.

[ember laurel]

I guess the easier version is to just tip in the serial number manually, but that's error prone, for the assembly person

[silk lark]

@ember laurel the microcontroller already has a unique number hardwired in it, you could use that...

[ember laurel]

true, there is the STM32 Unique ID

[ivory jasper]

Finally! I connected the last trace last night. Still have some things to check and a few minor changes to make but other than that it should be "done" 😄

[distant raven]

Nice!

[ivory jasper]

Here's what it looks like under the hood (without the filled zones)

[ember laurel]

@ivory jasper why do you need the DC jack?

aren't you powering over USB-C?

[ivory jasper]

@ember laurel Powered USB hub (and can make the LEDs brighter--if you want)

[ember laurel]

3A for those leds

blind those eyes

[ivory jasper]

You can use USB C or the barrel jack

Haha the LEDs only use up ~800mA at full brightness

[ember laurel]

looked a bit similar to that part of the PCB I'm working on 🙂

[fast tundra]

Yeah- when I program and test each product, I record the microcontroller ID.

[ember laurel]

ok, perhaps that is a good bet then - I can record that in the QC/calibration data

[tough matrix]

how do you access the MCU ID - for SAMD chips?

[fast tundra]

There's memories addresses in the datasheet that tell you where the bytes are.

One sec

[pearl tapir]

@ember laurel A low power laser will burn a serial number into the PCB. Coincidentally, the very black charred powder remains in the grooves cut by the laser. A quick spritz of conformal coating locks in a very high contrast label. However, the laser cut grooves are very readable and also permanent.

[fast tundra]

That's for the SAMD21, the addresses for the 51 are different, but you can search the datasheet for "serial number" and find it.

[ember laurel]

@pearl tapir which z-distance does such a laser need?

My assembled board is 15mm

[pearl tapir]

@ember laurel What ever is the focus distance of the laser. As I remember, It was greater than 15mm on the one we used. If it is a bit more than the optimal focus distance, the spot will widen but still may have enough power to cut.

[ember laurel]

That would need an exposed copper pad then?

[pearl tapir]

No. You cut into the FR4 substrate.
Cutting copper is very difficult as most cutting lasers are CO2 with a wave length of 1040nm. That just bounces off copper.

[ember laurel]

1040 sounds like deep red

Are there any addon heads for a Prusa that will manage this?

[unreal flax]

CO2 lasers are more like 10um, or 10,000nm.

[pearl tapir]

Oops: 10600nm is correct. Forgot as zero.

[ember laurel]

Do you need a dedicated laser cutter/engraver for this?

I thought going for stickers will be the easier option now.

Will do some 1000 units per year,m to start, so I need to save time as well.

[pearl tapir]

I had an Epilog co2 laser available that had lost some gas and was under powered. It has estimated at less than 20W, maybe much less. I have no idea what wattage is actually required. The Epilog was moving fairly fast but with less power one could slow down. But I don't know the lower limit.

Th goal is to "burn" not cut.

[misty escarp]

Do you have to worry about char bits getting into the circuit? The lasers I've used had a fan going that sometimes blew carbon around. That said they were hobbyist grade

[pearl tapir]

Mine did not have a fan that blew the charred powder out of the grooves. That was a plus as the boards were to be conformal coated and the black char increased contrast.

[stray atlas]

Been trying to find those SMD USB C connetors online for days and cant find any(backorder on digikey). Might have to use the TH version.

[misty escarp]

thoughts on mounting with M2s?

drawbacks?

[elder peak]

M2 screws or M2 SSDs?

[misty escarp]

haha screws

I see now that my question was very ambiguous

[elder peak]

M2 screws are tiny

Like, overall, always put screw holes in your PCBs.

A lot of my stuff is held together by nylon M2 screws and standoffs and mostly I end up needing to grab the magnifier when doing it because of how smol the screws are.

M2.5 is better, M3 or #6-32 are the two sizes of screws on a PC... but when you actually put a proper sized footprint for that big of a screw you look and think of the other bits you can jam into the board and so, at least for me, it ends up being M2 or M2.5

I guess if I was working on something that's going to see some mechanical forces, M2 screws would start to be a questionable design choice

[misty escarp]

I was thinking M2s because that's what some of the adafruit boards seem to be sized for

[distant raven]

M2.5 work just fine on Adafruit boards

I bought some M2.5 nylons that work great

[misty escarp]

Huh could have sworn they were 2.2mm holes

[distant raven]

100mil

2.54mm

[misty escarp]

man what board was I looking at where they were 2.2

[distant raven]

Sparkfun uses 2.2mm

[misty escarp]

ah

[ivory jasper]

Almost done! I need to get this reviewed somehow without spoiling the announcement though. The world's first open source hall effect keyboard!

[distant raven]

Or some of their boards do anyway

[ivory jasper]

Back side!

[misty escarp]

pretty!

what program did you use to make it?

[ivory jasper]

@misty escarp Kicad

...and I'm designing the case/plate in OpenSCAD

[misty escarp]

nice super open source!

[elder peak]

Well, here's hoping it's got magnetic attraction

[misty escarp]

weird question, if I put my .sch and .brd files on an open github, can anyone pull info about me from them?

[tough matrix]

yeah, the down to the names of your cats

[elder peak]

Everything you do in KiCad is timestamped

[misty escarp]

hm

wait I have cats?!

that's why I'm sneezing

[tough matrix]

seriously, though, what kind of info are you talking about?

you can open .brd file in text editor and see for yourself what it contains

[unreal flax]

He's probably worried about things like directory filepaths, user preferences, etc.

[misty escarp]

I can, I just wouldn't know what to look for

anything personalized

[tough matrix]

the only thing it might contain - and i doubt it - is the email of your autodesk acct

[misty escarp]

I guess I'll ctrlF a file and see

no danger opening a file I want to not be altered in a text editor right? as long as I don't alter any text?

[ivory jasper]

@elder peak It's magnetic separation along with optional magnetic levitation switches 😄

There's no springs!

[misty escarp]

wow! Perm magnets?

[ivory jasper]

@misty escarp @elder peak This is what the switches look like: https://gfycat.com/sorrowfulequaliraniangroundjay

You can't see it in that gif but there's a magnet in the body that's pulling on the magnet in the stem (which you can see). There's also a magnet under the keycap which is pushing away from the magnet in the body. So you've got both magnetic separation (the stem pulling away from the body) and magnetic levitation (keycap pushing/repelling away from the body upwards)

It's made for 3D printing and the switch is generated from a parametric .scad file. So you can control the travel, the force, etc etc

Yes, it's smooth, haha. Everyone asks that

[tough matrix]

@misty escarp I just checked
The only kind of personal info that .brd file contains is the version of your Eagle software

[ivory jasper]

The stem and the sheath it slides in and out of are printed with their layer lines parallel to each other || ||

[misty escarp]

Thanks @tough matrix that's what I gathered as well

[ivory jasper]

The keyboard case and top plate are also attached via (strong) magnets so you can take the whole top plate off and give it a good scrub in the sink if you want! https://gfycat.com/welcomeindolentcanary

[tough matrix]

neat

how are the two boards communicating?

I mean the top plate and the actual board

[ivory jasper]

@tough matrix The board uses linear hall effect sensors so the switches don't actually need to come in contact with the PCB at all. They're contactless!

Since there's no electronics in the top plate/switches you can just... pop it off! Main reason I designed it that way is because I hate cleaning my keyboard (it's so tedious!) but the other benefit is that you can have entirely different sets of switches/keycaps and swap them out at will. So if you're working you can have a normal switch but when gaming you could swap them out for some low-force, short-travel switches in an instant.

[elder peak]

Lots of neat features to cap-italize on, clearly

[vapid grove]

@ivory jasper cool

[ivory jasper]

Oh! I'd also like to point out that all the unused pins are broken out on the back of the board and there's a full set of I2S pins for hooking up audio. There's a QWIIC connector (with its own LDO!), 5V connectors, and a connector for the WS2812B-B LEDs so you can daisy chain even more LEDs off the keeb if you want. It can be your Christmas lights controller! haha

[vapid grove]

Lol

Also I see you used black pill in your numpad, which MCU does it have - F401 or F411?

[elder peak]

I wounder if you could just strap magnets to your fingertips and type in the air

[ivory jasper]

STM32F401CEU6

[vapid grove]

Ok

[ivory jasper]

...because that's what JLCPCB had loads of in stock when I started but now they have ONLY 25 LEFT!

Even though it hasn't gone through review I'm tempted to just order because I'm afraid they'll run out and I'll have to use some other chip

OMG they only have 15 now

[vapid grove]

Do you use circuit python?

[elder peak]

I'd be stm-ed if that happened to me.

[vapid grove]

I’m now inspired to build my own 65% keyboard

But in Mac-style

Because I’m a fan of MacBooks and I love apple’s layout

They made a great job reworking usual Cyrillic layout, and now it’s comfortable to print

At least for me

This is a regular Cyrillic keyboard layout

[misty escarp]

does it have a cute acronym like QWERTY?

[vapid grove]

Well, something like that

I’ll try to transcript that in English...

J - TS - U - K - E- N

But back to the classic layout problems

Notice how there’s a letter in the number row

Well, now it can be safely replaced with “E”, but I don’t like writing “E” instead of “Ë”

So now comes the fun part

This is the regular Apple Cyrillic layout:

[misty escarp]

that seems much cleaner.

[vapid grove]

Yes

Also, the letter “Ë” is now in the “letter” section:

And it’s much comfortable to print on that layout

Also if you want, I can record how “J - TS - U - K - E- N” is pronounced

[misty escarp]

If you like!

I'm having fun with my own guess so no rush 🙂

[tough matrix]

@vapid grove so you really care about ё vs е?

[vapid grove]

Sorry for my teenage voice

@tough matrix yes

[misty escarp]

I wish I could guarantee you'd grow out of it, but I don't think I ever did 😉

[tough matrix]

wait for another 50 years

[vapid grove]

Sure I will, I’m only 14, actually

[tough matrix]

wow .. pretty impressive. Few 14yr olds design their own PCBs

[vapid grove]

Yes, I know

Sadly, Adafruit doesn’t ship their boards directly to Russia, so that’s why I design my own

https://tenor.com/view/dan-op-wereldreis-jejsmajxnej-improvise-adapt-overcome-gif-14339274

[misty escarp]

that's unfortunate, hopefully they can change that at some point

[vapid grove]

Yeah

I hope I’ll be able to start something like Adafruit in Russia

And become the official partner of adafruit

To sell their hardware

[tough matrix]

that actually is a nice idea

whst city are you in?

[vapid grove]

Tyumen

Not a very big one

But lovely

[tough matrix]

and cold:)

i have some friends there

Adafruit actually has a distributor program, but it expects distributors to sell at least $10k/yr

which is a lot

[vapid grove]

So here’s the plan:

Make an electronic kit which is Minecraft themed

Port makecode to it

Sell it for a low price

Wait until it gets popular

And boom, now you can be an adafruit partner

[tough matrix]

well... the hardest part is "wait until it gets popular"

[vapid grove]

Yeah

[tough matrix]

you can start by selling through existing stores

like amperka.ru

[vapid grove]

Yeah

worst case scenario start cloning adafruit boards

This meant to be crossed out

[elder peak]

I mean, when I was 14, there weren't open source PCB CAD tools nor were there microbatching services, so if you wanted a PCB you had to fab it all yourself.

And do so by hand.

[misty escarp]

had to draw traces up hill both ways!

[elder peak]

Forget traces, how about drilling.

[misty escarp]

oof

no fancy soldermask designs either I bet

[elder peak]

Also, there are totally outright clones of Adafruit boards floating around on aliexpress.

So it's not like you'd be the first, LOL.

[tough matrix]

which is even legal - the boards are open source

but what really sells adafruit is documentation and community

[elder peak]

True.

[tough matrix]

which you don't get on Aliexpress

so i would suggest cloning that part - for each board you plan to sell, translate adafruit learn guide

[elder peak]

Also, I hopefully will be ordering phase two of the great absurd custom keyboard-from-scratch project shortly.

[vapid grove]

I didn’t find adafruit clones on aliexpress

Fortunately

[elder peak]

It's mostly the sensor breakouts.

[vapid grove]

Oh, I remembered, servo expansions

[elder peak]

Keyboards are fun because there's a whole lot of effort put into open source keyboard making community stuff so a lot of the stuff is not so hard.

Like, if you don't know about https://wiki.ai03.com/books/pcb-design/chapter/pcb-designer-guide you should

[tough matrix]

never tried making a keyboard..

[vapid grove]

I want to try

[tough matrix]

@vapid grove indeed, you are right - seems one can not easily buy say LoRA feather board in Russia

@vapid grove удачи!

[elder peak]

I got obsessive and figured I might as well.

I'm down to my last MS Natural Elite.

And I figured, in lieu of either switching layouts or paying for a vintage new-in-box keyboard, I'd just cook up my own.

And then I went on to use a matrixed keyboard for the controls in my new light painting board, so I guess it's kinda handy.

[tough matrix]

are there no commercial replacements for MS natural?

[elder peak]

MS makes a few split keyboards in various layouts that are similar but not the same.

[tough matrix]

ok

[elder peak]

Like, if I had to buy a commercial one, I'd probably just get the Kinesis Freestyle or something

[vapid grove]

Look who I got here!

[fast tundra]

What fab house made that? 😂

[misty escarp]

Just Little Cats and Pretty Cute Barkers

[tough matrix]

"A dog ate my homework"

[misty escarp]

I swear this diode doesn't have a marking 😦

If I find it, the line goes where the * is right?

[fast tundra]

I always love getting my assembled boards in https://twitter.com/wntrblm/status/1337845379015057409?s=19

Winterbloom (@wntrblm)

Just got a fresh crop of Big Honking Button boards in. We'll be fulfilling backorders and restocking after the holidays!

Twitter · Dec 12, 2020, 7:42 PM

[elder peak]

HONK

I presume, @fast tundra, that you already know about Ian Coldwater and their known predilections ?

[fast tundra]

Yes ofc.

I used to work at Google Cloud so I'm very familiar

[misty escarp]

eek, time to power on my board and see if it's borked! wish me luck

well

nothing broke but nothing works

I have my buttons just clipped in and not soldered, could that be the issue?

I was hoping I could test htat way

shoot something is wrong

redesign I guess!

I think I made a mistake in my button layout :/

oh well it's a chance to use larger diodes that aren't basically impossible to see

[fast tundra]

Always try to fix your current revision with bodges so you can save yourself a few revisions.

[misty escarp]

that's a great idea

I'm just not sure what I did wrong!

I thought I matched my breadboard exactly but apparently not

[fast tundra]

Time for some good old fashioned debugging.

[misty escarp]

yeah :/ I wish I had a scope or knew what I was looking for

we'll see

[misty escarp]

Hm I was trying to do one row of this

And did this:

IDK why buttons give me so much trouble

[elder peak]

I mean, it is a hot button issue for a lot of people.

[misty escarp]

I needed a snort-chuckle after today thank you @elder peak

does anything jump out as wrong to anyone? appreciate any other feedback as well

[tough matrix]

@misty escarp looks good to me.
except that the original schematics you are trying to reproduce didn't have resistors, but I expect this is intentional

[misty escarp]

Yeah it's intentional, the datasheet mentions them

And they work on the breadboard fine

I thought this was fine too, hm maybe it's the diodes they are real small and hard to place correctly

[tough matrix]

can you share your .brd file?

[misty escarp]

Yeah want the .sch too?

[tough matrix]

yes

will take a look later tonight

[misty escarp]

Hm it's giving me trouble uploading the .sch

ok if I try a PM?

thanks btw!

[tough matrix]

sure

[misty escarp]

sweet

[distant raven]

ready to order. Just have to wait a week or two 🙂

[fast tundra]

nice

[distant raven]

Mostly because gotta wait for bills to come out and see where things land

pesky bills

[distant raven]

Ya ever look at the costs of a digikey order and sigh because the shipping costs more than the parts for your prototype lol

[misty escarp]

Shipping is usually more than half of my JLC orders

[distant raven]

I think I might throw a few orders together.

[elder peak]

I basically keep a running tab of bits to buy that gets burned down a bit every month.

And then, the rest of the time, I add bits to the list.

So, my electronics purchasing habit is little more than a cat licking itself and then mysteriously finding the need to emit hairballs.

[distant raven]

makes sense

@fast tundra question for ya

is there generally a good value to consider for crystal stray capacitance calculations?

like the adafruit guide uses 5pF as an example but says sometimes you might assume lower of say 3pF

the 40MHz crystal oscillator I picked for my esp32-s2 board has a CL of 15pF, so that would put me at 20pF for my crystal caps if I chose 5pF

[ivory jasper]

I ordered it. Cost me $150 to get 5 PCBs with two assembled. Would've been $200 for 5 fully assembled but since it's the first prototype it may have mistakes so I'm thinking about it like it's a coupon, "$50 off your first borked PCB!" Hurray for the world's first open source hall effect PCB!

[misty escarp]

sounds Riskey

[elder peak]

All hall the new keyboard order.

[ivory jasper]

You guys are my type!

[fast tundra]

idk if I should feel happy or sad that my orders are always several times the cost of shipping 😅

[elder peak]

We have an obsession over shipping secondary only to fanfic writers.

[misty escarp]

zine fans too

[fast tundra]

@distant raven oh god that's mostly black magic

[elder peak]

Just to take a pico at the math is a lot.

[fast tundra]

you don't have to get the load capacitors perfect, you just have to get them close.

I have this from some random app note:

In general when you calculate the loading caps don't use anything lower than that

but a little higher is okay

👉 https://microchipdeveloper.com/faq:937 "In this example, do not use a loading capacitor below 21 pF. We recommend using the next standard 22 pF ceramic capacitor."

[elder peak]

So... if @fast tundra is here to explain clock issues for us in terms of ppm, does that mean she's one in a million?

[fast tundra]

I'm a fair bit rarer than that

[elder peak]

Okay, I think I'm done covering giant swaths of my board with thermal vias.

[fast tundra]

cool

[misty escarp]

fixed the board!!!!

thanks to @tough matrix for the pointers

you can't see but I'm doing a little dance

oh hm there is a weird issue with the repl output

Getting reads on all three keypad inputs instead of on just one

but that's ok for now

[fast tundra]

Awesome 😎

One of my new boards shorted out earlier and I have no idea why.

Second one worked fine

[misty escarp]

I feel like I squashed one bug but it just alerted the mama bug

[fast tundra]

These are fully assembled and they're a re-run, so I can't think of any reason why there would be a big fault like that n

Maybe I just goofed and shorted it somehow

[misty escarp]

sometimes the gods taketh

[tough matrix]

in case some of you are interested and haven't yet seen it on twitter:
Espressif is offering to send free ESP32-C3 board to whoever writes to them while supplies last
https://twitter.com/EspressifSystem/status/1337447836732932104
Sounds too good to be true, but then, it is official Espressif account - and what do we have to lose?

John Lee (@EspressifSystem)

Does anyone want free RISC V WiFi+BLE 5.0 ESP32-C3 dev boards that will also support ESP-RainMaker out of the box?

Likes

187

Twitter · Dec 11, 2020, 5:23 PM

[distant raven]

I was going to email them the other day and forgot

Thanks for the reminder @tough matrix

[distant raven]

Also thanks @fast tundra

I think the example in the ESP32-s2 data sheet used 18pF caps so with my crystal, I’ll use 20pF or maybe 22pF

[fast tundra]

@tough matrix not unusual at all

Lots of folks do samples

Analog Devices is pretty lose with theirs. I got them to send me a $20 DAC.

TI seems to not be quite as friendly

[tough matrix]

where have I been all these years 🙂

[unreal flax]

Coilcraft is also really good about free samples.

[elder peak]

In the heyday of Maxim magazine, I received some samples from Maxim. My wife was quite curious what the heck I'd done given that I've never been the Maxim magazine type of person. (Also, we'll note that, being a nerd, I'd heard of Maxim semiconductor before the magazine came out, much like I knew what a PROM was before I knew what a Prom was)

Also, my father-in-law, another an obsessive engineer type person, decided to make his own couch and managed to get the metal coil thingies for couches as samples.

[fast tundra]

Heh nice

[distant raven]

😂🤣😅

[quasi bloom]

thanks for the headsup

[pearl tapir]

@distant raven I usually find I can save a couple of dollars on shipping from Mouser and usually the parts are a tiny bit less.

[distant raven]

I usually do first class mail unless I really need something

[pearl tapir]

I usually do 3 day fedex 'cause I want the tracking.

[misty escarp]

speaking of tracking, getting excited watching my PCBs make their circuitous route from China to me

[pearl tapir]

There is a USPS depot near Atlanta in Ellenwood GA. I ordered some fresh baked cookies for a customer to the tune of nearly $100. They have been stuck in Ellenwood for 9 days waiting on the USPS to deliver. This is the so called "FEDEXSmartPost". What a misnomer.

[misty escarp]

and they're also delivering the covid vaccine 🙂 read usps as ups

[fast tundra]

@pearl tapir are you in GA?

[distant raven]

Post office is hit and miss for me

Sometimes they are early, sometimes they are horribly delayed

[pearl tapir]

@fast tundra Yes I am. Came here a long time ago to go to GA Tech and never left.
Sandy Springs, actually.

I believe you are also?

[fast tundra]

Oh snap we're neighbors

I'm in Chamblee

[distant raven]

Atlanta area is nice... to visit. Too hot for me

NC is even too hot

[pearl tapir]

That's what air conditioning is for.

[distant raven]

I like the outside

AC is bad for the environment too

And power grids in general

But so is most kinds of heating

But the cold is great because you can always add layers

You can only take so many layers off before it becomes illegal

[misty escarp]

I'm the opposite, I hate having layers on but I can handle being overheated OK

[quasi bloom]

NC is perfect at the right combination of altitude + longitude. but insisting on 3000' minimum does discount most of the landmass.

[distant raven]

I spent a lot of time of my life in western Wyoming

I spent a lot of time 7000+’ above sea level

Fall colors starting in mid-late august

[quasi bloom]

making me jealous ... that's hard to achieve east of the mississippi

[distant raven]

Yeah, I am at ~1200’ in elevation where I am at currently

Just south of Boone in the Brushy “Mountains “

[elder peak]

Everybody's always so lazy in western Wyoming. No pressure.

[quasi bloom]

too low for me. 3500' near the three-points.

[distant raven]

I’ll be moving to the LDS Capital I mean Utah state capital of Salt Lake City around March so I’m excited

[misty escarp]

Utah is gorgeous

[distant raven]

It has a beauty about it

[misty escarp]

check out park city it's beautiful

[distant raven]

I’m excited because it’s about 3.5 hours from where I grew up

I’ve been all over park city 🤓

I love driving by the ski jumps there from the SLC olympics

[misty escarp]

yeah! I remember seeing thsoe

only been once but enjoyed it

[distant raven]

And Yellowstone is nice when it’s not overrun

I spent a summer working in West Yellowstone, Montana

It was hard work but pretty fun all together

[misty escarp]

simplest board ever? Maybe

with a mistake!

[distant raven]

What is it?

[misty escarp]

Forgot pullup resistor

oh what is the board

It's gonna be for the air quality monitor I'm making for my parents. Button will wake the screen

qt haxpress will drive it all

[distant raven]

Nice!

[misty escarp]

won't be much compared to a real product but should be a fun project

[distant raven]

Indeed! I’m going to probably make a Wifi temperature sensor using one of my new ESP32-s2 boards I’m making

And probably the BMP280

[vapid grove]

Hey @distant raven, do you ship your products to Russia?

I’d like to try out your cp sapwing

[distant raven]

I’ve never done so but I can look into it

Shippo usually covers the customs documents but I’d need to look at what it would take to ship to Russia

[vapid grove]

Ok

[distant raven]

It would probably be >$30 to ship

But that’s just a guess

If that becomes an issue, maybe look at the micro s2 @plush phoenix makes

Unless your talking about the CP Sapling, which if that’s the case the Qt Py is mostly the same and cheaper and I know they have European distributors

[vapid grove]

Yeah, I meant sapling

Also, did you know that espressif officially made an arduino compatible board:

that's ESP32-PICO-V3-ZERO-DevKit

[tough matrix]

@vapid grove @distant raven pirateship.com, which is what I use for shipping, quoted the shipping price of $14.49 for shipping an 8"x6" envelope to Russia by First Class Package International; estimated time 1-3 weeks.
https://www.pirateship.com/usps/first-class-package-international

[elder peak]

PIRATE SHIP? AHOY MATEYS!

[tough matrix]

yeah, they do that. They make almost as many puns as @elder peak

[elder peak]

I mean, I was born on Talk Like A Pirate Day, so I consider myself part-pirate.

[misty escarp]

I'm working on the scars and limp, beard is coming a long thanks to quarantine

[unreal flax]

Does that mean you're irate? 😉

[misty escarp]

or p irate as the kids might say

[tough matrix]

3.14rate

[misty escarp]

lol

[vapid grove]

lol

@distant raven it seems like your website is down

[misty escarp]

works for me fyi in case that helps debug

[distant raven]

Website is up for me

[ivory jasper]

This is why we need 3.14pF caps

Calculating the correct capacitor will be as easy as...

[distant raven]

Lol

[tough matrix]

placed a new order for PCBs... my largest yet.
7 different boards, 10 copies of each
(in fact 20 copies, as each board is actually a 2-board panel)
Let's see what I get

[fast tundra]

nice!

it get scarier and scarier the more you order ime

[distant raven]

It’s true

[elder peak]

I got $200 of lasercut bamboo to make Christmas presents for folks and I was like "Ugh, I hope I didn't just buy expensive firewood"

[distant raven]

lol

[misty escarp]

my little medical themed charms/pendants/keyfobs came! A little smol for keyfobs but that's OK

[distant raven]

yeah, very nice! 🙂

[misty escarp]

Just gotta resin them and send out as gifts 🙂

fun trivia: that symbol I used? That's the "correct" rod/snake to use for medicine. The one on ambulances with two snakes is historically inaccurate

[distant raven]

oh interesting!

also congratulations on the promotion here on the server 🙂

also curious what Hello Kitty Island Adventure is @supple pollen

[misty escarp]

thanks! It was a surprise to be sure, but a welcome one

[distant raven]

you do help a lot of people out here, so very well deserved 🙂

[misty escarp]

aw thanks

[distant raven]

I'm hoping I can hit the commit level to be a Circuitpythonista 🙂

[misty escarp]

woot! I made my first step towards that recently too

[distant raven]

Check how chonky this SPI flash is

It almost doesn’t fit on the pads

[misty escarp]

I'm thinking of proposing a stemmafied 7 segment backpack board that also allows use of my committed code for keypads

[distant raven]

But totally worth the 8.3MB

[misty escarp]

chonker

[distant raven]

Also, I got new stickers today

[misty escarp]

woot. JLC has started shipping christmas themed keychains with boards

[distant raven]

Nice 3” stickers to seal packages with

only $19

[misty escarp]

nice!

[twilit mango]

@distant raven I can add you to the CircuitPythonistas role! There's no requirements for it. We do use it to notify about the Weekly meetings and the accompanying notes doc, so if you're prepared for/don't mind that, I can add you.

We also use it on the off chance we introduce awful bugs. Doesn't happen often, but.... it has....... 😄

[distant raven]

oh 🙂 I'm not sure how active i'll be in meetings but I'm finding myself adding more to Circuitpython 🙂

[twilit mango]

You don't have to be active in the meeting either! We welcome contributions in any way!

[distant raven]

It's the first thing i've contributed to where it feels like it's making an impact 🙂

well, open source projects that is

[twilit mango]

Done! Welcome to the role!

[distant raven]

hehe

😄

[misty escarp]

woot!

[distant raven]

gratzi 😄

[twilit mango]

prego 🙂

[misty escarp]

Promotions galore today. I'm hoping to get a show and tell tag soon

[distant raven]

I'm hoping to order some parts from DigiKey to show of a board I am working on for capacitive touch

AT42QT1070 capacitive touch sensor

[misty escarp]

I got part of my recent design working well enough for my purposes so I just need to finish bringing them up and I'm good to go

[distant raven]

wow nice! great job 🙂

[misty escarp]

it's got some kind of hardware bug but that's just details

[distant raven]

as long as you can work around it to prototype, that's all that matters

[misty escarp]

It's actually pretty serious but my code bypasses the problem fine

when I make it open source I'll put a $10 bug bounty on it if I don't figure it out

[distant raven]

hmmm

I need to start working on a driver for this capacitive touch board

will be interesting to do as I've never written driver code for an i2c device

[misty escarp]

CP or C++?

[distant raven]

both lol

the C part I'm not terribly concerned about

just making sure it's usable for Circuitpython is where it will be fun

[twilit mango]

@distant raven Using adafruit_register makes it a lot simpler. Though your knowledge level and focus may differ, and using Register could make it more difficult. For me, it makes all the difference in the world - without it I couldn't write drivers. (Yet, I mean... yes I could learn, but Register made it so I could do it with a lot less knowledge.)

[distant raven]

writing the driver will probably be pretty relevant to my new job I start in January so I'll try the rough way

[twilit mango]

Ah fair enough.

[distant raven]

if that doesn't work I'll give adafruit_register a try

thanks for the suggestion 🙂

[twilit mango]

Whatever works best for you, for sure! I think we're trying to move to using register for all of our stuff, but I know sometimes we still don't.

[distant raven]

also curious, I haven't touched tests/pyboard 2.py but apparrently it has changes that want to commit.

is that normal for things to just randomly show up?

[twilit mango]

Hmm it's happened to me, but no it's not "normal". Sometimes I merge something in and it's not in my branch and then it shows up as changes.

Or submodules do wonky things, not sure if tests acts like submodules.

[distant raven]

odd thing, it's a clean fork I had to redo for the current PR for adding the AT25DF641 SPI Flash

I jumped to main and then back to the branch

going to reset the head for that file so hopefully that won't break anything

[twilit mango]

That's the nice thing about git and branches... you can kind of break all you want, and you can still get back to where you started.

[distant raven]

yeah, I did git rm tests/pyboard\ 2.py since it was created some how

[elder peak]

I have no aspirations on this server other than the Master Punner role, a role I fill quite adequately.

[twilit mango]

@elder peak Everyone has their own goals 😄

[quasi bloom]

i'd vote for you
shocking, i know

[elder peak]

To be fair, I didn't so much aspire to attain the Master Punner role either, I just have a hard time not being one.

[misty escarp]

That's a very saitama like thing to say

[twilit mango]

That's really the only way to get the role.

[silk lark]

To conquer the world, achieve nothing. If you must achieve something, the world is beyond conquest.

[supple pollen]

@distant raven Hello Kitty Island Adventure is a joke game from an episode of South Park

[distant raven]

Makes sense 😂

[misty escarp]

materials safety: When I use leaded solder I pretty fastidiously wash my hands and everything i might have touched on the way to the sink. Is that still a good idea with non leaded solder?

[twilit mango]

@misty escarp Yes. It doesn't contain lead, but it contains other things that are worth washing off. Really, as long as you're not also putting your hands in your mouth or your mouth on the things you touched after leaded solder, you're fine. I wash my hands thoroughly after soldering, that's about the extent of my safety protocol with it.

[misty escarp]

I might be having a cross reaction with my covid carefulness tbh. Thanks!

[twilit mango]

You're welcome. 🙂

[tough matrix]

Lead is indeed dangerous, but most cases of lead poisoning are from peeling lead-based paint, lead in pipes (in really old pipes), or dust from cutting lead-containing materials getting in the air. Just touching lead is not that dangerous if you wash hands afterwards.

In my childhood we would melt lead in small fires to make various things, from fishing weights to knuckle dusters. I am afraid those of my friends who did use knuckledusters didn't always immediately wash their hands afterwards...
But then, it was not the most dangerous part about knuckledusters

[misty escarp]

https://tenor.com/view/starship-troopers-traitorof-mars-sttom-film-starship-troopers-bugs-attack-gif-8969856

my board apparently

[distant raven]

Bugs galore?

[misty escarp]

Turns out it's OK! But I'm sure my main board will be buggy

[distant raven]

Nice!

[astral elbow]

heya! i want some headers, male +female in both 2.54mm and 2mm pitch which will have the same height

[misty escarp]

do you mean stacking headers or male headers and female headers?

[misty escarp]

They came out great!

ENIG was expensive but well worth it

[tough matrix]

wow!

is it a Christmas gift?

[misty escarp]

Yup! for a spooky friend

Actually I'm giving them to a few people because I had to order 5

[distant raven]

Those are pretty nifty

[misty escarp]

I didn't do the design, i stole it off the internet

I DID finagle EAGLE into making it the right size though

[tough matrix]

I should explore kore the idea of making purely decorative pcbs..

[misty escarp]

It's fun! I also made some charms that I'm turning into earrings/necklaces

Black soldermask on Lead free HASL looks great.

[tough matrix]

maybe will order some business cards for my son

pcbs, of course

[misty escarp]

I'm sure the folks at JLC were confused

[misty escarp]

very cyberpunk

[tough matrix]

i am sure they have seen other examples of pcb art

[misty escarp]

probs actually

[tough matrix]

but pcb business cards is not a new idea: https://www.etsy.com/listing/908259894/circuit-board-business-cards-50-pack?gclid=CjwKCAiA_eb-BRB2EiwAGBnXXpWxv5wLjPT1IDvkr3lkfXo7eAVg6XCs6_orfelxaTSRtBe3QPiCZxoCw-4QAvD_BwE&variation0=1697378181

[misty escarp]

You could do 0.4mm but it would cost you a pretty penny

[fast tundra]

I actually have PCBway do my panels. They know the drill.

They're well used to me doing weird stuff.

Plus I've learned how to leave them good instructions.

This one was a fun one. I had to go back and forth with their engineers a few times.

[misty escarp]

Badum Tssss

[supple pollen]

That PCB is serving several functions at once, I like it.

[fast tundra]

They were very confused by the strange pattern of exposed fr4 on the backside.

I sent them a picture of me shining a light through it and they got it. 😎

[tough matrix]

oh, so this is how you got these led lights? it is literally through pcb

neat

how are the leds mounted?

[fast tundra]

They're smt LEDs that are on the board beneath that one

[elder peak]

I have never actually had any back-and-forth with the PCB manufacturer.

I clearly need to do more weird stuff

[fast tundra]

Clearly

[distant raven]

Really need to finish this BOM for the SapWing

[cerulean crest]

No, you are right, it isnt a new idea, one of my fav projects is linux on a business card

https://hackaday.com/2019/12/24/now-even-your-business-card-can-run-linux/

[tough matrix]

@cerulean crest is it your project?
I remember seeing a year ago, but I re-read it now - and I am completely blown away by how much time and knowledge it took to do that. Kind of makes your own projects seem trivial in comparison 😦

[cerulean crest]

No, its a favorite of mine, and for a while I wanted to make my own version

[elder peak]

So... it's in the cards.

[ember laurel]

Making myself a jig for PCB soldering

[misty escarp]

Does anyone see any issues with this? It's so simple I'm second guessing myself

[supple pollen]

Let's see, when the switch is actuated, the LED should come on, and A0 would see the forward drop of the LED plus the current drop through the 220Ω resistor. When the switch is not actuated, A0 would see the supply voltage.

However, if A0 is set as an output, hmm

[misty escarp]

Yeah I want to use A0 as input pullup

[supple pollen]

When it's high, and the switch is pressed, the LED would be lit brighter

You have an external pullup, so an on-chip pullup won't do much

If A0 is set as an output and grounded, not much will happen, there will be a small flow through the 4.7k resistor.

[misty escarp]

The switch state is meant to be used to wake an I2C screen

Added the LED so the user has something pretty to look at

Had a prof tell me they got a product funded because they added an LED and the VC person liked the blinking so now I consider them essential

[misty escarp]

Does a joint like this count as 90 degrees? Where each trace meets the pad as shown?

[pearl tapir]

Probably. I prefer to run the long trace to the one centered between the two pads but I probably tend to over engineer things.

[misty escarp]

And make it come in at an angle?

hmm EAGLE doesn't seem to want to do that :/

[pearl tapir]

No. Just move it to the right a little so it goes only to the trace between the pads.
I can't help you there I use Mentor Pads Pcb.

[misty escarp]

Oh is that a "better" 90 degree joint?

[misty escarp]

That's better than underengineering 😉 I'm always trying to learn the best practices so I appreciate the input

[pearl tapir]

What you have is one pad with three thermal sinks that will tend to twist a component as the solder cools. Solder has a self-aligning torque and if all the forces are equal, the component will center on the pads. The way you have it, the forces on pad on the left will not be even. Is it a big deal? No. Unless you want to build to 6 or 7 sigma defect level and then everything matters.

[misty escarp]

Three thermal sinks? The two power planes and the pad itself?

Something like this being better?

[pearl tapir]

Yes, imho.

[misty escarp]

Cool, I made my power planes much smaller too

[supple pollen]

I like big power planes and I cannot lie

[quasi bloom]

that's a QTpy? powering w/ direct 3.3v to the 3V pin? i thought that was output-only

[misty escarp]

This brother from another mother can't deny

[misty escarp]

I'm using the output as my pullup voltage. Power input is a wall jack via the USB port

[quasi bloom]

ahh, gotcha. "not shown on schematic." should've realized it was something else. thanks!

[misty escarp]

Yeah good callout tho. This is just for my parents and they only know eagle as a danger to their small dogs, but I should make it more professional anyways

[distant raven]

@quasi bloom you can feed a regulated 3.3V into the 3V pin

I found out after some research that most voltage regulators have body diodes or can act as body diodes which is interesting

And unrelated, but totally PCB related: got my box of parts from Digi-Key 🥳

[silk lark]

well, they are a mosfet with a feedback

[distant raven]

Just waiting on the PCBs to come tomorrow

Yup

[tough matrix]

I never knew what is inside an LDO

[misty escarp]

I just tore up a trace on a 99% completed build

ruined the whole thing

[tough matrix]

any chance of repairing it using a thin wire?

[misty escarp]

well ruined is a strong word. I can run wires the device "wrong" and it still works

but I have to make it the last device in a chain since I ruined my in stemma qt connector traces

[pearl tapir]

@tough matrix Often the data sheet will give a simplified schematic that shows the output configuration.

https://www.diodes.com/assets/Datasheets/AP2114.pdf

[tough matrix]

yeah, I understand how one can find it.. it is just that I never got to that page :)
But maybe it is about time

[fast tundra]

Finished up my reflow oven build. What a journey.

[distant raven]

Loving the Halloween feel

[misty escarp]

French press & keurig, always prepared

[elder peak]

Ooooh, the world needs a reflow oven with a speaker so you can hear the wails of flux leaving the solder paste like ghosts being converted into pure ectoplasmic energy.

[elder peak]

Also, my latest box of bits, which had been in an indeterminate state since last Friday, finally arrived, with a powerlifting bonus because the guy dropped my neighbor's package off on my doorstep as well. My neighbor's package was a 25lb weight.

[distant raven]

Geez

It makes no sense to order weights online when they can be easily purchased in a store

[elder peak]

Man.

That's heavy.

[misty escarp]

insert doc brown gif

[elder peak]

But, also, we're in shelter-in-place here so I guess folks want to avoid the stores.

[misty escarp]

we're shelter in place advisory but no one is doing it

it's gonna go real well I can tell

[elder peak]

I mean, I'm obeying it. I've got doc brown hair.

[supple pollen]

Me too!

[misty escarp]

I thought her cardigan was a lab coat for a minute

[supple pollen]

That would have been perfect!

[rigid dove]

crossposting from #help-with-projects ,

https://www.actinius.com/icarus
https://www.nordicsemi.com/Software-and-tools/Development-Kits/nRF9160-DK/Download#infotabs

i understand one of these is sold by adafruit, so i know there will be some bias, but which one is better?

i want to end up using this chip in my own board, so maybe the DK is better as schematics are public, i dont need BT or any of the connectivity options provided by the official DK besides LTE

[misty escarp]

I can't give a definitive answer but the featherwing form factor is really great, as it (obviously) fits feather boards

[vapid grove]

Guys, is it possible to use a regular oven as a reflow one?

[unreal flax]

You don't want to use a real kitchen oven because it will contaminate your food, but people have been able to convert toaster ovens into reflow ovens with replacement temperature controllers.

[ember laurel]

jig works 🙂

I need to make those pins 3mm instead of 2mm though

some carrying handles would also be nice, but this is really at the limits of my printer

[ember laurel]

now I just lack the hairnet and the mandarin skills

[supple pollen]

You could add some holes at the edges for carrying handles, print the handles separately, then snap/clip/screw the handles onto the jig. Actually, removable handles might be (ahem) handy.

[ember laurel]

yeah that could work

would be nice to have a sort of fixture to put them into the ultrasonic bath as well

this just for the prototypes though

perhaps I shouldn't bother too much 🙂

[tough matrix]

@vapid grove just talk to @fast tundra , she is doing exactly that right now
another option is using electric skillet/crepe maker

[distant raven]

Question for those who have PCB Mills

And not OtherMill by Bantom Tools

Does the milling bits that Bantom Tools sells for the OtherMill work with other desktop milling machines?

Also, has anyone used the SainSmart milling machines?

[fast tundra]

@vapid grove I used a hot plate for a long time before going the oven route, if you only do one board every now and then that's the most cost effective way.

[pearl tapir]

@distant raven I've used a T-Tech PCB mill and as far as I know, PCB end mills are .125" carbide. For outlining traces, T-Tech (and others) recommend an engraving bit. Generally, you want the widest bit that will get the trace spacing that you use.
If you need to hog out a wide area, use an end mill and use a side cutting end mill to cut the board out.
Most of the modern CNC routers like Carbide3d Nomad or even a Shapeoko will probably work for simple prototypes. If not, you probably need to get them etched.

[distant raven]

I’ve used a PCB mill before, I just wanted to know if the bits are compatible

[pearl tapir]

If they are .125", then yes. It's a standard size and the pictures on their web site look like .125". But it is possible they grind them to some odd size.

[distant raven]

I just don’t want to pay $2500 right out the gate

Also, how is the software that other mills use?

[ember laurel]

how are the cheapo mills from China?

[pearl tapir]

The T-Tech is locked down with a dongle. I don't recommend it. I think I'd build my own instead, probably a Three Design PrintNC which is ball screw driven. A small one of those would not be to expensive.
There is some open source PCB milling software like FlatCAM.

[distant raven]

Ugh, covid + holiday mail delays are the worst

Had some PCBs that should have arrived today apparently delayed

😓

[supple pollen]

Having the snowplow destroy your mailbox is pretty bad too.

[distant raven]

Ouch

[tough matrix]

My DHL delivery from Shenzhen is expected on Wed, Dec 23... fingers crossed

[ember laurel]

enough soldering for tonight

all those LQFP's and QFN packages take their time to hand solder

[distant raven]

Wowza

[ember laurel]

I really should get a fume extractor as well

I get the boards like they are on the left, minus the LQFP and QFN.

fortunately not hand soldering everything...

[fast tundra]

@ember laurel time to get a stencil & reflow oven/late

[ember laurel]

@fast tundra I ordered these with most components already in place

[fast tundra]

oh they're partially assembled

aw

[ember laurel]

no way I'd do all 0603's on there

[fast tundra]

0603s aren't too bad, but anything lower than that I struggle with.

why are the smd parts only partially assembled?

[ember laurel]

I ordered from JLC

they don't have everything stocked

comes like this

[fast tundra]

ah gotcha

[ember laurel]

minus the whiskey

[fast tundra]

we do all of our smt stuff through MacroFab and then place surface mount stuff ourselves (since its more cost-effective at our scale)

[ember laurel]

I just do this for this batch of prototypes, need to have them out before xmas

takes time to setup an assembly line otherwise

[fast tundra]

yeah

we're about to start working on 150 jackboards (13 potentiometeres, 11 jacks, 2 pin headers) for our newest module.

that's gonna take some time. :3

[ember laurel]

I'm working with a factory in China to handle the series production

[fast tundra]

Ah cool. I try to keep as much as I can in NA.

[ember laurel]

why?

[fast tundra]

It's easier for us to communicate requirements and easier to maintain quality control.

[ember laurel]

I see.

I have had good work from this factory before

I come from the audio industry really

[fast tundra]

plus we don't have to deal with importing our own product. 😛

[ember laurel]

that factory does tons of audio stuff usually

for the bigger brands

[fast tundra]

ah cool

Overseas is great if you have a good relationship with a factory, but it's really hard to build those relationships IME.

We have a good relationship with PCBWay for our panels (our panels are just PCBs), for example, and we have a good relationship with a specific manufacturer of audio cables for our patch cables.

[ember laurel]

Yes, sure. We have personal connections since many years now.

[distant raven]

I love the production process which is a main motivator for me doing as much as I can in the US

Plus doing it in the US is an interesting challenge that only a few companies have successfully done at large scale

I’m not very certain that my operation will ever be terribly large at least in pursuing my own designs. If I ever get decent equipment, I may contract manufacture boards for people

[ember laurel]

it's just incredibly difficult to compete with the Chinese prices

[distant raven]

Oh I know

[ember laurel]

if you have a product which will see scale, it's close to impossible to do that anywhere else :/

otherwise your competitors will just outprice you

[distant raven]

And that’s a risk worth taking I think

Hobbyist in general I think will opt for cheaper fabrication, but some people will pay for local manufactured equipment. And some companies will pay for that as well

It’s an uphill battle, but doable if you find a niche

[ember laurel]

it's just getting better that I think is hard

the good plants in China are just really great.

and they all work Monday-Saturday, 8am-9pm

it's nuts.

plus I get stuff shipped from Shenzen or Guangzhou to here, in 2 days.

[distant raven]

Yeah, I find the US’s biggest problems are:

1. Unwilling work force (most don’t see the value in domestic manufacturing, so they generally don’t want to train for those careers)
2. Government doesn’t want to invest in domestic companies trying to build up a domestic supply chain, rather they spend billions on overseas companies who have no intentions of following through

I’ve met so many goi g for engineering degrees who don’t actually want to be engineers, just PMs

And not to mention the vast number of people who go for business and finance where there is already a shortage of jobs for those careers

[ember laurel]

yeah I wonder what I will push my kids into 🙂

feels like half of the jobs here are in finance actually

[distant raven]

And then grade school and secondary schools not aligning curriculum to teach children to be inventive

I know so many people who “hate math” because they see so few people using it in the real world

[ember laurel]

heh...

[distant raven]

But i think most people hate math because they didn’t have a good teacher

[ember laurel]

it's probably more the parents

not saying that teachers don't matter

[distant raven]

It’s a combination of teachers and parents being disconnected

[ember laurel]

but if kids get curiosity and manners from back home, they will go get it on their own

[distant raven]

Or having incoherent dreams and aspirations for their children

As a parent, I hope that I don’t do that to my children

[ember laurel]

Yeah, I try to do what I can for mine.

[distant raven]

I want them to see me get curious about a problem, design something, fail, and then try again from a different angle

[ember laurel]

We severely limited screentime for the kids, and they got SO much better.

[distant raven]

We only allow TV shows that encourage imagination and creativity

[ember laurel]

ipads and TV is just terrible for kids

kids need to be bored

[distant raven]

iPads are for road trips because my kids get horribly car sick

[ember laurel]

out of boredom grows creativity

[distant raven]

Yup

[ember laurel]

Oh well yeah, I agree with that. Road trips is the exception

We usually do math quizzes on road trips, but at some point they get tired 🙂

[distant raven]

Yeah 🙂

My kids are 2 and 4

[ember laurel]

mine are a bit older

4 and 7

[distant raven]

They use ABC mouse

[ember laurel]

7 year old already has a computer, but she really only uses it to do certain tasks for school

[distant raven]

Makes sense

[ember laurel]

I like that my son, 4, enjoys playing chess though

[distant raven]

We get my kids involved with cooking, cleaning, and whatnot

My son is a bit speech delayed so he’s just now getting to the super emotionally expressive stage

[ember laurel]

Our boy was also tons later than our daughter with speaking properly

[distant raven]

My daughter on the other hand is sharp as a tack

My son is too, but in different ways

[ember laurel]

same experience here

it's great to see

[distant raven]

He has a very broad imagination whereas my daughter is more analytical

She loves puzzles

[ember laurel]

as analytical as you could be, with 4 🙂

[distant raven]

🙂

[ember laurel]

My daughter was never into puzzles, that's more for son.

[distant raven]

I’ve been working with my son on the concept that you can love everyone

Right now he only loves his mom, is cousin, and his dog

[ember laurel]

with the age of 2, you're teaching him philosophy?

😉

[distant raven]

He’s 4

Lol

[ember laurel]

oh

[distant raven]

Daughter is 2

[ember laurel]

world of difference

[distant raven]

If I tell him that I love him, he says “no, I only love mom” haha

[ember laurel]

and dog

[distant raven]

Basically

[tough matrix]

don't get me started on the problems of math education in the US...
I have been involved in these discussions as parent and as teacher for the last 20 years... I can't take this anymore

@ember laurel how large a production run are you planning?

[distant raven]

That’s right.. it’s terrible for sure. I appreciate the work you’ve done to try and fix things

[tough matrix]

we try to fix things locally - running enrichment math classes, math circles, etc - and working with gifted kids, this I had been doing for the last 35 years, ever since my own high school graduation
I know several professional mathematicians who were involved in global efforts - rewriting elementary school syllabi, promoting different teacher ed initiatives... with mixed results

[distant raven]

I think part of it is the everybody wants to be an artist syndrome

But people don’t realize you can make beautiful things with science and math and engineering

Not to say there isn’t value in art, people don’t realize that it’s engineering, math, and science that makes art possible

[ember laurel]

@tough matrix depends on how successful the product is. I estimate perhaps 600 units in year 1

3000 for year 3

But who knows, could be 100 units in total 🙂

I at least have minimum orders for about 1000 units over 3 years

[tough matrix]

wow

[ember laurel]

Mind you, the margin isn’t very high

[tough matrix]

as long as it is positive 🙂

[ember laurel]

I hope to break even 🙂

Depending how highly I value my time.

I also gotta pay some 50k USD to get a CB

[tough matrix]

cb?

[ember laurel]

CB cert.

[tough matrix]

oh
it is that expensive?

[ember laurel]

Electrical, EMI testing and so on.

Medical Device, so testing is crazy

[tough matrix]

yeah, with medical I expect there is a lot of requirements

[reef flicker]

Hey guys, I've got a quick question.. I found a (slightly cheaper) alternative to the sensor I was using

The only difference as far as I could tell is it's marked as "for harsh environments" rather than for water-resistance
Harsh environment: https://www.st.com/resource/en/datasheet/lps33w.pdf
Water-resistant: https://www.st.com/resource/en/datasheet/lps33hw.pdf

I'm not sure what the difference is between harsh environments and water resistance

[reef flicker]

The compare tab lists these two with different package dimensions too, even if their datasheet deffine strictly the same size

[distant raven]

Well, harsh weather is a bit more broad than just “water”

But both list weather stations as an application

[reef flicker]

According to the naming convention, the W stands for waterproof, with no such thing as "harsh environment"

Since I'm buying a bunch, it may be good to get the cheaper one but idk if I'm going to regret it

They certainly will have water and organic matter on them

[distant raven]

If water proof is a necessity, I wouldn’t cheap out

[reef flicker]

well i need the H anyways

[heavy jasper]

Reading through a bunch of the documentation... it's not obvious to me that there's a clear answer. I suspect there may have been some modifications of ratings/product lines at ST somewhere in the middle of making these products.

In that they originally wanted to differentiate between the HW and W for different features, but then decided that they'll only make one. Or someone copy-pasted very badly in making datasheets. The "Harsh Environments" they're talking about are "long-term exposure to harsh environments such as water mixed with chlorine, bromine,
commercial washing detergent and fuels, solvents and chemicals" and the big example they give is for smartwatches that end up in chlorinated pools.

Some hardware guidelines here, originally written for the HW: https://www.st.com/resource/en/design_tip/dm00452854-lps33hw-digital-pressure-sensor-hardware-guidelines-for-system-integration-stmicroelectronics.pdf

But that now appear to be equally valid for the just-W variant, based on this section of the LPS33W:

[vapid grove]

That exact feeling, when you read MEMS as memes 😉

[misty escarp]

A SIC MEMS

[reef flicker]

@heavy jasper i read through the same documents, and have to agree that something weird is going on

Maybe they changed their minds? Idk

It looks like the internals are the same, and the only significant difference is the accuracy

[heavy jasper]

Oh, is the accuracy actually different?

[reef flicker]

Perhaps they decided to skip over some of the waterproof testings

That's what the H stands for. They're rated at different levels of accuracy

Or noise as they put it

But there is also a difference in how they describe the water resistance layer (waterproof vs harsh environments)

[heavy jasper]

It does look like the HW is slightly better absolute accuracy on pressure, though the noise specs appear to be the same.

[heavy jasper]

Looking at the datasheet, that appears to just be the internal filter/cal on vs off

(and the same thing is listed on both datasheets)

[reef flicker]

Yeah there's some odd stuff going on with that compare sheet

I'll just bite the bullet and take the 50¢ pricer model

Man these are pricy... I need 10 for the project and at 8$ a pop it stacks up fast

[heavy jasper]

You may be better served with a different module if you're not going to take advantage of the extra sealing features on this one.

In that here, it's not just IP67 as a module but intended to be an exposed port on an otherwise sealed module

[reef flicker]

Yes, I'm also buying o-rings

They'll slot right into the 3d printed part

(with a little luck and soldering madness)

[heavy jasper]

Also I think I linked the wrong hardware guidelines above, this one seems more useful: https://www.st.com/resource/en/application_note/dm00420205-lps33hw-digital-pressure-sensor-guidelines-for-system-integration-stmicroelectronics.pdf

[reef flicker]

The sensors are between the board and the part

Yeah I've read through that

Those dimensions of o-rings are not exactly easy to find at a reasonable price too

[heavy jasper]

Not massively surprising

Most folks who would do this for a product would get a custom O-ring specified for their design

(so, $$$$s of tooling then each part is ¢s)

[reef flicker]

I would've assumed that someone designing a part meant to be used with an o-ring would use a more readily available dimension

But eh, ordered a bunch of sizes from china and we'll see

[vapid grove]

Guys, I decided to make my own keeb

But I can’t find the difference between these jailhouse switches

CPG151101D06 and CPG151101D92

[vapid grove]

Also, which module adafruit uses in their nRF52840 boards?

[unreal flax]

Looks like it's one of the Raytac MDBT50 modules, from the schematic label. https://www.raytac.com/product/

[ember laurel]

@reef flicker That looks awesome! How does it work? How do you sense the airflow in each opening?

I also take it that you are doing Bluetooth midi?

[silk lark]

is this a mouth organ?

[reef flicker]

@ember laurel there is an array of 10 air pressure sensors mounted on the side of the PCB we don't see (towards the 3d printed part). They can detect human breath and communicate MIDI with the computer

No plans for bluetooth midi at the moment to be honest. I've got enough on my plate 😁

[ember laurel]

Sounds awesome.

Bluetooth midi, and rechargeable battery - would be absolutely killer

I imagine getting each slot airtight to the other, with a nicely controlled airflow - will be the hardest part here

Also no idea if you can nicely “bend” notes like on a real harmonica

I even don’t know what actually happens when you do that.

@reef flicker still totally love your project though, and I hope to hear more about it!

[silk lark]

I'm working on an electronic ocarina, but didn't figure out which sensor to use yet -- either pressure or just a microphone

[elder peak]

I guess I can say that I'm blown away by these project ideas.

[tough matrix]

I was prompted by question from @distant raven and dug out my old project of making a manual pick-and-place machine
sure, it is questionable if manual PnP machines are of any use at all, but for those of us whose hands are not so steady, it could be useful
My plan was to make one using a construction set goBilda (used, in particualr, by many First Tech Challenge robotics teams), so as to minimize the amount of required laser cutting/3d printing
Here is my draft - what do you think? would it be useful?
https://a360.co/37zEJr3

[reef flicker]

from my testing, pressure sensors are easier to work with

But since in your case you don't need to draw breath as well as a blow, then I guess either could work

[silk lark]

yeah, I need to just do some experiments

[reef flicker]

Microphone I wasn't able to get the precision I really wanted

[misty escarp]

So is it each sensor corresponds to a note? and then the note gets played if the sensor detects over a threshold?

[reef flicker]

Since you rely on the noise of air moving, it's not really as precise, and there's many other factors to consider. What if you're playing with a band? Or in a noisy environment? The mic will tend to pick that up. Worst case, it will start "playing" by itself while you're on silences because of a loud guitar solo

[reef flicker]

For the harmonica? Yeah, this render shows the "inside" part of the PCB, the one that mates into the 3D printed part https://ferdz.needs-to-s.top/8Wz2QgL.png

[misty escarp]

I'm biased because I think they're awesome, but I think you should consider a stemma qt port for your I2C signals

[reef flicker]

What are they 😅

https://learn.adafruit.com/introducing-adafruit-stemma-qt/what-is-stemma-qt these connectors?

[misty escarp]

yup!

[reef flicker]

Yeah that would be much nicer than headers pins 😛

[misty escarp]

they are a little harder to solder than the pins you have but there are out of the box connectors for them that adafruit sells

[reef flicker]

A bit late for this version since it's in the mail but next time

[misty escarp]

how long of a cable are you using btw?

[reef flicker]

For connecting it to the mcu? As small as I got... Think about 20cm?

How would I setup that connector to work on an off the shelf mcu board?

[misty escarp]

Hm that's a good question.

I thought your MCU was on that board for some reason

[reef flicker]

It's not (yet)

Opted for the itsybitsy a user suggested

[misty escarp]

Ah yeah they make short versions of the cable that have a stemma on one end and jumpers on the other but it's pretty short

which MCU?

[reef flicker]

I'm getting pretty cramped on space, idk if I'll be able to fit the MCU directly on the sensor strip board, but I'm thinking I can mount it on top of the other board and hold it on with header pins

Atmega32u4

[misty escarp]

oh cool beans

[reef flicker]

And I'm scared of designing my own MCU board, even though looking at it it appears to be quite simple

[misty escarp]

The 32u4 shouldn't be too bad

[reef flicker]

https://learn.adafruit.com/introducting-itsy-bitsy-32u4 just from looking at it, it doesn't look like it's very difficult... Maybe I could grab the files and modify it to only have the pins I need

[misty escarp]

Yeah cribbing off adafruit is a good idea 🙂

you shouldn't need many pins either

[reef flicker]

Technically only the 4

gnd, 3v, clock & data

[misty escarp]

and programming pins 🙂

and reset button

[reef flicker]

Through the USB no?

[misty escarp]

ah I think we mean different things heh

[reef flicker]

Yeah, the pins on the outside

[misty escarp]

Ah yeah, I meant on the MCU when you make your own

[reef flicker]

Completely (kinda) unrelated note. I'm looking for cheaper providers for my sensors. Found a listing for it on alibaba, and after contacting the seller they're asking for a (much) cheaper option than I could get here

Is it too good to be true?

[tough matrix]

regarding programming:
before you can use USB, you need to put a bootloader on the chip

for AVR chips such as 32u4, it is commonly done using so-called ICSP header

see e.g. https://learn.sparkfun.com/tutorials/installing-an-arduino-bootloader/all

[reef flicker]

Hmm.. I'll have to do some research on that

For this version it's pretty out of scope, but maybe eventually it will be useful

[tough matrix]

it is not that hard

[misty escarp]

I have to decide if I'm gonna buy a real programmer, gonna try using an arduino first though

It's among the several tools missing from my toolkit

[tough matrix]

note that for m0/m4, you need a different programmer

it is architecture-specific

[misty escarp]

yeah, I have seen a guide for adding CP with an arduino so gonna go with that first

[reef flicker]

Are programmers just USB dongles of some kind that hook into those pins?

[tough matrix]

basically

[misty escarp]

$100+ dongles T.T

[tough matrix]

e.g. here is one possible porgrammer for AVR: https://learn.sparkfun.com/tutorials/pocket-avr-programmer-hookup-guide

nah, it is more like $20

for m0/m4, you can use this https://www.adafruit.com/product/3571

[misty escarp]

Ah I was looking at the more expensive model I guess

[tough matrix]

if you do not need commercial - i.e., not selling your product - then EDU version is fine

[misty escarp]

oof that price increase

[tough matrix]

commercial SEGGER costs like $400

[reef flicker]

So running back to the alibaba supplier, anyone has experience ordering parts from there?

[tough matrix]

I did, but I only ordered cables

they turned out fine

[misty escarp]

I've only heard it's hit or miss

[tough matrix]

what sensors are you looking for?

[reef flicker]

LPS33HW

For 1 harmonica (10 sensors) they turn out to be almost 100 CAD, so that's a bit steep

Trying to save a little bit on them, especially since I'll probably destroy a few

[tough matrix]

mouser gives price of US$56

for 10

I have my doubts about ordering them on AliBaba. Unlike connectors or enclosure boxes, this is something must be produced by STM, not by a random manufacturer

[reef flicker]

You're right

They're distributors rather than manufacturers

[tough matrix]

maybe. I don't know. What price are they offering?

[reef flicker]

2.85 USD/pc for 20pcs

[tough matrix]

half the price of mouser

[reef flicker]

Which is significantly lower than anything else I've seen

[tough matrix]

unfortunately lcsc.com doesn't have them either
this is the only chinese electronics distributor I used