I've been trying to get to grips with WiiMote Physics in the last week or so. It is a piece of free software which utilises Bluetooth connectivity on your PC to receive data from a Wii gaming controller.

A WiiMote has three accelerometers and an infra red camera inside. Using these it takes 100 measurements from each detector per second.

This makes it an ideal device for measuring many types of dynamics effects in physics.

I first used this capability of the WiiMote at the Physics Summer School using the accelerometer and IR detection for logging the simple harmonic motion of the WiiMote oscillating as a mass suspended from a spring, and swung on a string as a pendulum.

As my Advanced Higher Physics class have been working on the rotational mechanics part of the course I thought I'd try to do a qualitative measurement of centripetal acceleration against angular velocity using an air bearing turntable.

Placing the WiiMote radially on the disc, it should measure the centripetal acceleration in 'g' in the +Y direction. The angular velocity isn't as straight forward, being calculated from the period of revolution. The period is measured using the IR detector which 'sees' a lamp as it passes each revolution. This gives a regular peak on the trace for the IR detector.

At least, that's the theory. In practice its been somewhat trickier to achieve. There have been a few foibles to overcome -

  • getting the WiiMote to connect to the PC via Bluetooth
  • getting the software to show a reading from the IR detector
  • geting the IR detector to 'see' the lamp
Luckily, I have the brilliant support of the  Scottish Physics Teachers Network (SPUTNIK) an email forum, that has been great (as always) at offering help when I've detailed the problems I've had.
It's been a steep learning curve, but I think I'll be able to get some measurements done with my AH class next week. Fingers crossed....