View Full Version : Motion Plus capabilities

03-14-2011, 07:05 PM

Reading through the forum posts, I've seen a couple of suggestions that using the motion plus , I could track the position of the wiimote in space. Being a bit of a novice, I've not been able to make that happen as yet. Am I right in thinking that I have to in some way combine the motion plus data with the standard accelerometer data of the wiimote? Ultimately I just need a dot to move around a Quartz Composer screen that relates to the position of the wiimote on a stage. I don't need height either, just X and Y.

Thanks for any help,


03-15-2011, 06:38 PM
Hi Andy,

Regarding the MotionPlus device, the data OSCulator gives is the best I could do in terms of data analysis (it could be much better!).
The gyroscopes and accelerometers measurements are fused together to give an approximation of the absolute angles.

Computing the absolute position is tricky. You could try by fusing together the raw accelerometer and raw gyroscope data, but you will also need to add the IR sensors in the mix because the sensors are drifting. It is not as "simple" as solving an equation with 6 unknown variables.

The company that designed the Motion Plus device sells a SDK to perform the necessary calculations, unfortunately it is only available for the Wii (obviously), at a hefty price.

I was hoping to be able to perform the calculations myself, but without the necessary technical information I spent 2 months trying to integrate the gyroscopes' angular velocities in a way that minimizes the drift. It was very instructing but too demanding.

If you need to track a X/Y position, and if this fits your requirements, I would recommend you use reactivision, a software that converts camera signal to TUIO messages. OSCulator is able to interpret TUIO messages to make them easier to use.