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Unread 09-12-2013, 10:27
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Re: Team 2471 swerve drives

Quote:
Originally Posted by magnets View Post
That's really neat. I've ever thought of using two different sensors, an angular rate and an absolute rate sensor as two different sources of feedback for a PID loop. Out of curiosity, which compass sensor are you using and have you had interference issues in the past?
We are using a 9DOF IMU called a GY-85 which we got on ebay for $16 including expedited shipping (from Hong Kong so still took a week). It has a 3axis compass, 3axis gyro and 3axis accelerometer all on a single I2C bus which we tied to the DSC. The board is tiny (< 1 sq. inch) but does not have a processor. We read the X,Y magnetometer values and compute atan2 on the cRIO.

We originally mounted it on the main electronics board - which worked fine for debugging I2C and gave accurate compass readings... until we drove the motors. We moved it to about 18" above the motors and that seems to be fine. We have not tested it with other robots on the field yet, but given 18" was enough we are hopeful it will not be an issue.