Using a different gyro on a turtlebot

Question

Hi folks,

We are building our own TurtleBot and I am having problems with the IMU.

I am using the SparkFun ADXL203/ADXRS613 IMU (SEN-09127, http://bit.ly/jw6iUL).

What I am experiencing when I try to calibrate it is similar to the problem described at: http://answers.ros.org/question/1333/turtlebot-calibrationstill-waiting-for-imuscan

[INFO] [WallTime: 1308820084.864965] Estimating imu drift
[INFO] [WallTime: 1308820085.165909] Still waiting for imu
[INFO] [WallTime: 1308820085.466922] Still waiting for imu
[INFO] [WallTime: 1308820085.767989] Still waiting for imu

...but I haven't remapped anything.

The IMU is wired to +5V, ground and AIN on the Create through the pinouts on an Element Direct BAM (http://bit.ly/iHaTB8). The BAM isn't the problem; AIN passes through to pin 4, just like it should. When I first saw the problem I wired the IMU up to +5V on a bench supply and slapped a multimeter between RATE and ground. When I move the IMU around, I can see the voltage change, so the IMU is working.

If I look at /imu/raw and move the Create around manually, the X/Y/Z values remain at 0 (I don't have the accelerometer pins connected to anything, FYI), so I know that the problem is somewhere between the IMU and the ROS gyro stuff.

I know that my next troubleshooting activity is to see if the Create is actually receiving what the IMU is giving it, but I don't really know the best way to do that, and in any case my gut tells me that this is a software or configuration (not hardware) problem.

Does anybody have any suggestions?

Alaina - Singularity University - Mountain View, CA

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Originally posted by Alaina on ROS Answers with karma: 121 on 2011-06-29

Post score: 1

Answer 1

here are good instructions for adding a sparkfun gyro: http://answers.ros.org/question/717/is-an-imu-required-to-run-turtlebot-stack

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Originally posted by mmwise with karma: 8372 on 2011-06-29

This answer was ACCEPTED on the original site

Post score: 1

Answer 2

That IMU you showed on sparkfun looks like it only has outputs for I2C. Are you sure you listed the right one? That one doesn't have a RATE pin.

The best way to verify operation is to trace it every step of the way. You said you can see the voltage change. Is this change appropriate for the sensor and your expectation? Does the voltage go up when rotating one way and down when another?

Is there some sort of application that you can use to verify what the BAM reports? Or get some sort of printout?

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Originally posted by Chad Rockey with karma: 4541 on 2011-06-29

This answer was NOT ACCEPTED on the original site

Post score: 1

Answer 3

Thanks to mwise, we figured out that there must have been a loose connection. We attached the same IMU via a different connection to the bay's DB-25 and it's working great now!

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Originally posted by Alaina with karma: 121 on 2011-06-29

This answer was NOT ACCEPTED on the original site

Post score: 1