PS3 accelerometer modding help

[binary1230]

Hey guys, I'm trying to do something really goofy and possibly insane.

I'm working on a making a machinima series and I'd like to build a custom controller for it that replaces the PS3 controller's accelerometer with 3 joystick axes (or 2 pots or 3 knobs or whatever, just something that's easier to control than trying to tilt the controller around)

I'm a bit of an electronics n00b so I'm looking for any insights into how to go about doing this, or just pointing out flaws in my plan here.

I've been searching around for a couple of days as to what the specs on the acceleration sensor are and the only info I've found about it is from this one site which has a monster list of apparently every single part inside the PS3, including the controllers:

http://www2.electronicproducts.com/Sony ... xt-10.aspx

According to it, the part is:
Hokuriku HAAM-325BA Acceleration Sensor - Piezoresistive, 3-Axis

Looking at pics from Ben's PS3-in-360-case controller mod:



That's the accelerometer sensor there, looks like there are 4 wires, maybe 1 for ground, and 3 for each axis?

If that's the case, I'm thinking it would be pretty simply to pull out that ribbon cable, figure out the resistance range of the accelerometer axes, splice in 3 of my own variable resistors + other stuff that match the same resistance range, and it should work?

I was going to wire this up to probably another gutted say PS2 or original xbox controller that just has the pots for the sticks and no original PCB stuff in it (or something similar), so the final result looks like a PS3 controller with an xbox controller attached. Two people could then control the character - one for the normal movements on the PS3 controller, one for the fake "motion-sensing" movements on the xbox controller.

Anyone have any thoughts on that approach, or any more info on how the accelerometer works, or things I should watch out for? If not I may crack open a PS3 controller tomorrow and give this a shot. At the very least I should be able to test this theory by hooking up the existing sensor to a multimiter and measure a change in resistance when the orientation changes.

-Dom

PS: If any of you guys were at Magfest this year to see Ben's stuff, I run the concerts/jamspace over there.

[RDC]

That part number and the pic you're looking at are for 2 different things, what's in the pic there isn't the Accelerometer. Ya can't have a 3-Axis Accelerometer with only 4 wires, the math just doesn't work. The Accelerometer is built onto the board and it has been for every controller version so far. It could be on the top or bottom side of the board, just depends on the version of controller ya have and what Accelerometer they put in there. It'll either be on the top side, upper/left corner or on the bottom side, upper/right corner of the board.

There are also 9 versions of the PS3 controller right now, so the first thing ya should do is take your controller apart and see exactly what ya have.

http://forums.xbox-scene.com/index.php?showtopic=648322

Then see if ya can find the datasheet specific to the Accelerometer in your controller and just go from there.

Ya aren't going to be measuring differences in Resistance either, but differences in Voltage on the 3 different Axis of the Accelerometer. After that it's not much more than making up a voltage divider with a few Potentiometers and yer done. You'll most likely have to remove the Accelerometer from the board as well, having it on there as well as your alternate setup could cause issues with how it works.