ATtami strikes again 2021

so we had a revival of ATtami (wiki, github) last tuesday

compared to last run at 2015(!), there were only around 6-8 workers around.
and that was good.
while we seem to have made good boards, the micronucleus firmware allouded us.
couldn’t get the damn thing to identify over vusb.

the ATtami-tester repo provided good sanity check with a hex file that goes over all pins. to verify ATtyin85 connection.

but it doesnt cover the usb port, for that we need to cut a cable usb cable. make better test jig.

pre-workshop the lack of a good programmer gave lot of grief.

but it sorted itself out with tip from kfir

well almost.

ariel took on himself to actually wire the SOIC clip to the usbasp programmer header.
it was 50mil pitch so Ariel had to improvise. but came out well

btw, this type of headers can pass as a pogo pins when at 3am.

so the baking went well. we used tzvi tried and tested oven controller. this morning i got a “quickchip” type of solder paste. at 135deg (as opposed to the regular ~200deg i usually use. recommendation of harTzion boss. dont have a pick as i left it at tami fridge, this things get dry…

more image on the googPhotos

thanks to @morgan @LambertW @Ariel @444b @batya @Jonathan and the bio gang that swooped us

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the big big balagan is getting the micronucleus to identify on the attiny
it “used to work”

i can hand out attamis to whomever want to give it a go. but maybe next workshop we work on a better test jig and this issue will solve itself, idk…


another week another workshop, come tonight @7pm to tami

ATtami tuesday 05/11/21 > siran edition

before during and after we got a few more boars baking.
@dyln fixed the stencil we used to apply proper paste.
look at those paste lines on the usb pins!
next week we will fire up tami’s stencil cutter and make a new one.

@shumzi continued his adventures from last week with setting up a burning station on the ubuntu nuc, after serendipitously getting the micronucleus bootloader to burn on first try he stated work on refreshing the bootloader burning documentation. rudely interrupted by…

guests from the hookah place next door, some truckers barging in, a bit scared.
we didn’t notice the siran and they came looking for shelter.

shelter was given duck&cover, etc.

later that night @Almot finally got the bits in place to burn our first
1209/5222 attami – on a board.

also, we are out of solder paste. this thing should last longer but technique is lacking!

again, thanks to @LambertW , ariel , benji, noam , JB(!) and jonathan, who is just a great host and always bring someone/thing new to the mix. thanks for a weird night


so we had a low key event after the armageddon of last week.
just a bit of awesome work on attami-tester walkthrough by ariel

and we looked at some old timer knowledge.
Knuth chapter 7 on bitbanging
Forest Mimies introduction to electronics

and we totally off topic on the PVC curtains/divider for the metal shop project.

and dyln working the sewing machine

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love the updates!
keep it up :slight_smile:

tomorrow we continue the attami adv.
with special guest appearances by the elders of tami (tzvi)
who will discuss design choices going into a 1EU/5SHEKEL dev board.

also here is a gif of the first real use of an attami originated in our workshop. doing I2C to neopixels

wow, almost a month without updates. but the weekly grind continued

first off, our yield is horrendous, probably close to 10%.

we used to have around 85% good out of oven, with most of the issues around the damn micro USB connector.

i blame the noobs

the issue is the lack of proper workflow
in previous workshops we used to have dedicated teams doing assembly line type work, so people got used to the work. and got proficient
solder paste application-ers was done 10-15 at a time by few people (and they learnt how not to waste paste).

assemblers got good at putting things the right way.

bakers tuned the oven heat profile to fit the paste (we use currently some low temp (130c) which is not so hot (hha)

QA was done by one/two people, this is the hardest part and lack of proper hot air workstation is evident.

programmers had a good jig to work with, and tests where better tuned.

an in-circuit programmer

a pre-bake IC programmer

the new post-bake programmer

so all this “bad” things are just what happens when people try their hands in doing the full flow for the first time (with little guidance from “big daddy”).
its a different flow and one that gets you all the way from a-z but you dont get good at any of it. just sort of get the hang of things. usually the 3-4th run gets you a working board. but people are having fun, and one day i’ll get to sit and debug the rest… or just heat them sang the ATtintys from the bad boards and start fresh.
as u see im not terribly upset . even with this poor yield everyone got a working board if they whish. and some came back 2nd time, and more , to get good at things.

every week new people come, even if its just one or two, sometimes 5-8. it doesnt matter. i enjoy this and some weird way. all the little shit that happens when you bake boards. all the nice breaks outside in the street. its all good. the pressure is out the door when you work to learn.

next workshop tommorw, 22th june from 8pm