so i did it i finally did it i finished the whole design and i got boards made and i ordered them from JLCPCB and they’re coming in two weeks and it’s gonna work and it’s so good and we’re so back 
sorry for the break, life comes at u fast, but i am coming to u with progress! i don’t necessarily endorse this version as i have not tested all of it, however all of the additions are relatively mild (1M bleed resistor on the output, that’s pretty much it) and the rest is some pretty aggressive cuts to get it across the finish line (remove the optional current sink because it didn’t look like it was gonna pan out, remove optional current limiting diode because it’s impossible to source and kinda not necessary, remove the feedback inamp because it was inconsistent and potentially causing issues and anyone who needs to know the output current can just use more advanced tools to measure it, remove voltage configuration entirely and hard set it at 16 V because current is mostly the only number that matters anyways). these removals allowed me to fit it into a 100 mm x 100 mm square which will save costs. this definitely isn’t a sure fire build of things but it’s not bad odds that things work on the first try!
board is updated on https://git.sr.ht/~_410bdf/sphynx, exports for JLCPCB live in https://git.sr.ht/~_410bdf/sphynx/tree/main/item/Electronics/Boards/Lite/Lite%20Alpha%201/jlcpcb, this is theoretically orderable but maybe hold off until i make sure it works. while i wait for it to arrive i’ll be working on materials for putting together the peripherals like the probe and the pedal and getting the site up to date.
this is a haphazard and short update but i’m back and i have made a significant amount of progress since we last spoke and things are looking good <3
will share more later! let’s chat in the comments! love you all! bye!! 
mid-update-cycle update: it passed review and is getting made 
Hiiii ! Just created an account for this. Have you ever thought of using a USB-C Decoy, like with a CH224K, a resistor and a USB-C connector directly on the PCB. I have one that can give 20V from a USB PD. I guess it would be better than a pair of 9v batteries ?
Maybe once you’ll have confirmed your PCB works, I’ll take it and change things up a bit to add that and possibly a reset button, since the one I tried to do from that 8 year old reddit post included both of these features.
Anyway, I wanna thank you for your amazing work, you’re helping the trans community so much by doing that <3
I’m not smart enough to tell what you’re making, but I can tell that it’s impressive!
I just came across another DIY electrolysis design and had to come back here to share it with you: https://gitlab.scd31.com/stephen/hair-electrolysis-machine-hardware
I’ve been tweaking their design so that all smd components can be assembled using single sided economy pcba at jlc, and my version should cost ~$25/board after shipping with only THT component on the back to be hand soldiered: https://github.com/KibbieKatt/hair-electrolysis-machine-hardware
I haven’t ordered my version yet but I plan on doing a run. I’m curious how the cost of yours is working out? My version has a bunch of extended library parts which I think adds a lot to the cost. I had to also swap some diodes because they were too small for economy assembly.
Oh god, thank you for replacing the ESD441. I’m moderately good at electronics, and I’ve spent a good 8 hours trying to understand how to choose a diode to replace these, since I can’t found ESD441 on AliExpress, and I don’t want to use JLC other than doing the PCB and the stencil (assembly is expensive, and I can’t stand the way they handle the components (bit of a “you’ll own nothing and be happy”))
So I think the replacement I selected is probably good (it has a slightly lower working voltage of 5v but the breakdown is still like 7v so it’s probably unlikely that the USB voltage will be higher than 5v enough to cause issues), I ended up replacing it again with less protection because I forgot to select a basic or promotional component to avoid another loading fee when doing PCBA. I’m down to $20-30 per pcb after shipping and tariffs for qty 5/10, not including the hand soldiered components or other parts like needles, foot pedal, battery. Those are the other major costs and it looks to still be 50-70 per unit. So I think I may have shaved off about as much as possible from the PCB components, but if I can redo the PCB to put everything on 1 side, I maybe could avoid like $30 of shipping for the remaining hand soldered parts from lcsc.
The shipping costs for each of the additional parts adds up to a lot, especially since it’s like 2 parts from adafruit, a couple from lcsc (which you could probably include all the SMD parts in the same order for almost no extra cost, so getting that d-sub pin from eBay or somewhere for like $15 free shipping to eliminate the lcsc order should go a long way).
You’re welcome! I actually don’t know if it’s a perfect replacement, but I’m going to have an electrical engineer friend of mine review my changes before I order. I’m also only moderately good at electronics and only designed a PCB twice, mostly copying reference schematics. I’m just hoping to polish up this person’s design and round some of the rough edges that make ordering it hard / confusing (like getting rid of jlcpcb warnings and stuff). I’m halfway through the BOM trying to swap anything that’s an “extended” component with basic variants since I want to do single sided assembly since I hate SMD soldering, so just trying to make that cost go as far as possible. But moving the last diodes to the other side hopefully makes it easier to hot plate solder it too.
