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Wiimote/Extension Controllers (view source)
Revision as of 07:18, 23 June 2009
, 07:18, 23 June 2009→Data Format (Wii Motion Plus): Units, and method
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−While the Wiimote is still, the values will be about 0x1F7F (8,063).
+While the Wiimote is still, the values will be about 0x1F7F (8,063), although it is best to calibrate for a few seconds every time you start, to get the actual zero values.
+20 represents turning at about 1 degree per second. So divide by 20 to get the degrees per second.
+The gyros are slightly noisy, so you should assume any speed less than 0.5 degrees per second is actually zero, otherwise you will get lots of drift.
+Note: The definition of yaw, pitch, and roll, are slightly different for the gyros and accelerometers. Accelerometers measure angles relative to gravity. Gyros measure angles relative to the Wii Remote. If the Wii Remote is up the right way, then they are the same. But if the Wii Remote is on its side, then what the gyros call "pitch" is actually what the accelerometers would call "yaw".
+The correct way to measure orientation is to maintain a rotation matrix (or alternatively a quaternion) of the current orientation (relative to gravity), and update it each time you get a gyro reading. It will drift a little, so you should reset the matrix's pitch and roll (but not yaw) with the values from the accelerometers whenever the accelerometers and gyros indicate no movement. After significant rotation, you should reset the matrix's yaw to zero when the Wii Remote is pointing near the middle (horizontally) of the sensor bar.
=== Hardware (Wii Motion Plus) ===
=== Hardware (Wii Motion Plus) ===