Hello,

I am trying to find out the bandwidth of the ADXL330 accelerometers used in the Wiimote. I took one apart and removed one of the capacitors connected to the ADXL330 (Cx in fig. 1 of the ADXL330 datasheet). The datasheet can be found at (link works as of 01/21/08):

http://www.analog.com/UploadedFiles/Data_Sheets/ADXL330.pdf

Measured the capacitance with an LCR meter, it was 0.2 uF. Therefore, with a nominal R_{FILT} of 32k (p. 3 of ADXL330 datasheet), we get a bandwidth of (p. 12 of ADXL330 datasheet) 25 Hz.

But on Johnny's projects page (http://www.cs.cmu.edu/~johnny/projects/wii/), it says: "It also contains a +/-3g 8-bit 3-axis accelerometer also operating at 100Hz".

I don't understand what "operating at 100 Hz" means. Does it mean the BANDWIDTH of the accelerometer is 100 Hz? If so, could anyone please enlighten me on how to obtain the accelerometer bandwidth? Or does it mean the Wiimote is sending accelerometer data out via bluetooth at 100 Hz?

Again, any help is appreciated.

Thanks a bunch!!!!

I am trying to find out the bandwidth of the ADXL330 accelerometers used in the Wiimote. I took one apart and removed one of the capacitors connected to the ADXL330 (Cx in fig. 1 of the ADXL330 datasheet). The datasheet can be found at (link works as of 01/21/08):

http://www.analog.com/UploadedFiles/Data_Sheets/ADXL330.pdf

Measured the capacitance with an LCR meter, it was 0.2 uF. Therefore, with a nominal R_{FILT} of 32k (p. 3 of ADXL330 datasheet), we get a bandwidth of (p. 12 of ADXL330 datasheet) 25 Hz.

But on Johnny's projects page (http://www.cs.cmu.edu/~johnny/projects/wii/), it says: "It also contains a +/-3g 8-bit 3-axis accelerometer also operating at 100Hz".

I don't understand what "operating at 100 Hz" means. Does it mean the BANDWIDTH of the accelerometer is 100 Hz? If so, could anyone please enlighten me on how to obtain the accelerometer bandwidth? Or does it mean the Wiimote is sending accelerometer data out via bluetooth at 100 Hz?

Again, any help is appreciated.

Thanks a bunch!!!!