It appears the old monome github wiki is no longer accessible. I managed to find the original tutorial on archive.org, and I figured I’d add the details here for everyone’s benefit.
I have an original, unmodified monome 40h, and I plan to open the unit up to add an accelerometer. Since the referenced dual-axis accelerometer breakout board is no longer available, I’ve gone ahead and ordered a modern 3-axis board, and I’ll post the pictures after I perform the mod.
using the standard firmware (which uses the four aux inputs as analog) you can connect an analog accelerometer directly, no reprogramming required.
i used one from https://www.sparkfun.com/products/retired/844 for about $35 i think?
it has a nice breakout board, so the soldering is easy, and the passives are all included. not much to it: solder gnd to gnd, 5v to 5v, AY and AX to two analog-in pads on the logic board. that’s it. i taped it up flat on the back so it would stay level-ish. probably would be better to mechanically mount it with some sort of screw. leave long leads on the wires! also we haven’t tested this, but in theory it’d be good to add the 0.1uH inductor where the green jumper lives (next to the usb port on the logic board). this should smooth out the analog signal.