Using the standard firmware (which uses the four aux inputs as analog)
you can connect an analog accelerometer directly, no reprogramming
I used one from from sparkfun for around $40:
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. Mechanically mount it with some sort of screw.
this seems to work much better:
the black block is nonconductive foam to help stabilize. also the accel
pcb is trimmed to fit better into the enclosure.
Below are some shots of the Analog Devices ADXL-320 (-/+ 5g) accelerometer on the newer logicboard, which looks a little different from the older one in the pictures above. The accelerometer was glued to a small piece of rubber (inner tire from a bike, kind of) on top of the chip to keep it in place. Colors of the cables in the photos are not of importance, as they were just randomly picked. The ADXL-320 can be bought from Sparkfun.com