In my confusion I bought wrong JST headers (it’s 1.5mm, I bought 2mm), so I just went ahead and wired it myself:
Using the voltometer I checked the right polarity, and voila: the right half works perfectly; even if the left half has no LED strip attached dimming and animations work fine:
I’ll omit the video showing the animation and color changing; it’s too huge for an upload.
Next up, left side.
Expenses so far:
1x 10 USD for the 1st PCB prototype (5 pc) - unfortunately I was 0.2mm off on both measurements, so it did not fit
1x 1.95 CAD for wrong JST headers
1x 10 USD for the 2nd PCB prototype (5 pc) - which fits and attaches fine.
1x 10 CAD for 50 RGBW SK6812 LEDs from aliexpress.
so, not too expensive; also I learned a little why the PCB in the ErgoDox EZ is what it is which was great fun:
the ErgoDox EZ strip has 3 pads (vcc, data, gnd) on the left and 3 pads on the right side - turns out this is super useful! If you solder the LEDs rotated by 180 deg. - which I did at first - you can rescue the PCB by using the other side, as all pins still match. I had to throw away the entire row as I was unable to get the LEDs off cleanly. So that’s going to go into rev 0.1 I guess
Once I’ll have the left side working too I’ll open source the gerber files on github