SwiitBoard: high impact Wii balance board

[wraggster]

http://hackadaycom.files.wordpress.com/2008/12/swiitboard.jpg

[Frits] sent us the SwiitBoard, an improvised version of the Wii balance board. He wanted to be able to do something a little higher impact than he could on the Wii balance board, and required more space to do it in too. Using two different kinds of foam and a piece of plywood, he put together the SwiitBoard. We’re not completely clear on how he is handling direction control. He states that it is derived from gforce.x. Can anyone clarify? Stay tuned after the break for a video of his demo software.

http://hackaday.com/2008/12/09/swiitboard-high-impact-wii-balance-board/

[theotherfreakyguy]

G forces are GlovePIE commands, and GlovePIE is a scripting program for programming Wiimote Input to be interpreted as certain things. The Readme says:

The Wiimote also has three accelerometers which measure forces/accelerations, in each of the three dimensions. Force and Acceleration are basically the same thing, since the mass is constant (F=ma). In GlovePIE they are labelled like this: X is to the right (of the wiimote), Y is up (from the wiimote buttons), and Z is forwards (or wherever the wiimote is pointing). This is the left-handed Direct3D system.

If you drop a Wiimote and it is in freefall, all the forces will be zero. BUT if you are holding a wiimote up so that it doesn’t fall, then you are pushing it upwards with a force equal to the force of gravity, but in the upwards direction. If you hold the Wiimote flat then the force holding it up will be in the +Y direction, but if you point the Wiimote at the ceiling then the force holding it up will be in the +Z direction. This helps us measure the Wiimotes tilt as well as its acceleration.

There are three values that you should never use anymore, because they are obsolete and only for backwards compatability: RawForceX, RawForceY, and RawForceZ. If your script is currently using them, then replace them with the calibrated force values below. Remember the calibrated force values don’t need an offset, and they are about 1/30 the size of the RawForce values.

There are three calibrated force values:

gx, gy, and gz

They can be zero for no force/acceleration, 1 for the same amount of force/acceleration as gravity, or any value in between or outside that range. There is also the vector version:

g

The accelerations above are effectively measured in Gs. You can use them for measuring actual acceleration, or for measuring tilt.