Well I said I'd never have to build another box after my last all-out
Pro Midistim build but then diglet goes and drops a whole new technology on us!

It cost about a fifth as much, too.
Put it together yesterday on some single-sided stripboard and wondered how long it'd be until someone made a PCB. Good on ya puste!
It's just in a temporary (cardboard) box for now. Took about 4 hours all told, but I was being pretty meticulous with planning and cutting jumpers, cutting strip traces neatly with a burr bit in a rotary tool, etc. Made sure it worked on the scope (200 ohm 1/4w loads was fine as a test), then went for a ride.
WOW, it's good. Seems way less "raw" than running the same pulses on my audio rig, less susceptible to electrode resistances shifting, but can still pack a punch when scripts whip around quickly. I think you don't as easily hit the "pain threshold" with it... I made it to about 70% power with the latest current maximums.
Pics:
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Mounting the board definitely seems the trickiest part! I sewed it onto the stripboard in the corner with some floss around the daughterboard cutoff points, then staked it down to three separate strip rows at the outputs. The stripboard happened to fit perfectly lengthwise in this box, and the microUSB cable I chose happened to fit perfectly through the cardboard, so once connected it's in there pretty solid. Would love a 3D-printed box for it all, but somehow still haven't forked out the cash/effort for a printer. Other than that, maybe those DIN-rail-mount PCB holders could work?
For mounting the ST board to a custom PCB, I wonder about copying the through-holes by the USB Micro connector to the mainboard, then anchoring them down with headers or pieces of wire along with the outputs. Then the board is anchored with solder on two corners at least, and the USB could be run to a bigger PCB-mount jack, or a connector for a panel-mount cable. I'm a fan of the old USB-B you see on printers, but C is good space-wise. But man I wish ST had put some mounting holes on it...
Other things I'd like: A proper barrel jack instead of my dangling tail inline one of course, gotta add a volume pot, USB-C PD trigger for power maybe. I'm not jumping to add a battery but the option might be nice.
Diglet, do you know how this design could be adapted to use the "Trodes pan" section of TroniC's design? For reference:
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I presume just the same concept but with only 3 pots/6 jacks? I feel like I'm the only one who uses it but I love asymmetrically splitting the common between perineum/balls and anus, that's still my go-to on audio boxes. Maybe the pots could be lower-wattage now too?
I think this concept could compete with the Coyote honestly, though I don't have one to know for sure. The board is so small, even smaller when the daughterboard is removed. Paired with the right driving microcontroller, battery, BMS, protocol, open source non-spyware app? Now we're cooking with
Also sorry I missed your posts @DPL, I was thinking it could be that as I read them. Been burned by the power-only cables many times to the point where I now put a small red zip tie around them whenever I happen to find out I wasted time with them. Fingers crossed for you.