Hey @noisio, I bought a kit from you at #37c3. These synths you made are genuinely so fucking cool and I had a blast building them (and now playing around with them)

Thank you so much for going through the stress and programming one more microcontroller for my LFO/EG even though you were super busy helping others get their stuff to work. I really appreciate it <3

I didnt quite finish my ATBase at congress but now (at 6am) I can exstatically say I got it to work!

#noisio

@noisio Its still a bit janky because I didnt have a DC power jack anywhere at home so I just cut apart an old usb C cable I made and soldered the two power wires to the battery pads you put on there.

The usb cable itself I wired through the DC jack hole (after removing the jack) which unfortunately didnt work at first.

I had to bridge two of the dc jack pads which I did with that lovely green wire and voilà! A PERFECTLY WORKING ATBASE THAT SOUNDS SO FUCKING COOL.

#NOISIO

@Nici Hey, nice hack! I am glad that it's been working, but a bit surprised about. Actually you'll need more than 7V for the analog part and as well as input for the 5V regulator.
How much provides your USB-C charger? Do you have a meter to measure it? I'am curious about...
USB-C Power Delivery can give you up to 20V, but for this you'll need a small extra circuitry.
I've planned to change all the kits for USB-C in future, so you're ahead of the times :D
@noisio Thats interesting. I considered wiring up two 3.7v LiPo batteries in series (7.4v) in order to provide the energy, but decided against that because I first looked up the attiny85 specsheet which that stated the maximum voltage it can handle was 5.5V. I didnt want to risk it so I went with 5v, somehow missing all indicators stating that anything between 7v-20v was okay 😅

@noisio The usb cable I used was a Type A to Type C cable. I primarily build mechanical keyboards and decided a while ago to get into making the cables myself and that was one of my first attempts that didnt turn out too great. Perfect for reusing :)

I cut off the type C part and exposed the wires there, The other type A side I plugged into my lab bench power supply that provided the ATBase with 5v at 2 amps (I checked with my multimeter, 4.99v)

@noisio
>USB-C Power Delivery can give you up to 20V, but for this you'll need a small extra circuitry.

Uff, tell me about it. You dont want to know how much time I spent in order to actually somewhat understand how usb c pd works.

usb c for all future kits sounds bloody awesome!

@Nici the ATBase circuit is very close to ATPC https://github.com/noisio/ATtiny-Punk-Console/blob/master/docs/ATPCv3.pdf
The 78L05 needs 7V as input according to dartasheet. I also use the higher voltage as headroom for the analog part.
So I am now very curious what voltage do you measure at the ATtiny while having 5V at the power in(?).
ATtiny-Punk-Console/docs/ATPCv3.pdf at master · noisio/ATtiny-Punk-Console

ATtiny Punk Console Docs. Contribute to noisio/ATtiny-Punk-Console development by creating an account on GitHub.

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@noisio Oh shit, your right. I just read the datasheet too! Thats really odd... Unfortunately I wont be able to test it for you before sunday. But Now I'm interested in this too. I'll keep you updated.

Judging from my video in the OP I wouldn't say it sounds much different than the ones you had on display at #37c3, right?

@Nici No hurry for this. I also will investigate in this in the upcoming weeks. So this is quite interesting for me.
The sounds seems to be fine. But hard to say from here. The headroom is only needed for the very deep frequencies, which will start to distort.
More interesting is how the uC is powered. Maybe the 78L05 is bridged somehow? We will find it out ;) keep me updated!
@Nici Today I could take time to look how this is possible and if I can reproduce it.
And, yay - you found a nice little hack! If I put 5V into the 5V regulator it outputs 3V which is still enough for an ATtiny. Seems that it keeps the 2V reduction.
With this there is now a volume loss, which not hurts .. it's still loud enough.
But also adds some distortion to the output. So you're now more on the dirty side :)

@noisio oh dont speak to me about regulators today 😂

I fried my only esp32s2 devboard I got gifted at congress this morning and spent the majority of today researching this thing's schematics to understand how those little fuckers work until I eventually found another board I could steal a similar regulator from.
The difference was, it had a completely different footprint so I had to handwire the whole thing with directly to the pads... It was a pain in the arse to say the least. BUT IT WORKS!!

@noisio ESP rant aside, thats really cool to know. Powering the synth with just usb voltage is a lot more convenient than taking a dc cable with you everywhere :D