Gyro's angle value going up

[Mike Bortfeldt]

Originally Posted by GeeTwo

We could not find a "drop-in" replacement online, so instead we've ordered some 3-axis I²C gyroscopes from Pololu. It's on a closeout discount, but being replaced with a compatible upgrade. They had 189 until we ordered 20. We'll figure out how to use them on our practice 'bot next week.

Gus,

I've used similar gyros in the past and was not happy with their performance. In my experience, the Analog Devices gyros seem to give much better results. It's certainly possible that the newer models from Pololu have improved, and I would be interested hearing your opinion of them.

Mike

[GeeTwo]

Originally Posted by Mike Bortfeldt

I've used similar gyros in the past and was not happy with their performance. In my experience, the Analog Devices gyros seem to give much better results. It's certainly possible that the newer models from Pololu have improved, and I would be interested hearing your opinion of them.

Having learned what I have in the past few days (see this thread on usfirst), I'm not surprised; the gyro class uses hardware acceleration unavailable to an I²C gyroscope. While we will look at the suggestions there, there's the possibility of using an arduino to turn the I²C gyro into a rotation encoder, or just buying an integrated solution. The NavX would also be under consideration if it were actually available.

[FlyOldPlanes]

If you want to null out a small rate like that, you can use the setDeadband method in the Gyro class. we were a little confused since it shows up in the c++ version of the code, but not the java version. Look at the gyro.java code posted here:

https://usfirst.collab.net/gerrit/gitweb?p=allwpilib.git;a=blob;f=wpilibj/wpilibJavaDevices/src/main/java/edu/wpi/first/wpilibj/Gyro.java;h=ea1e1cc301c71243e091206312fa281fb2f5e5 87;hb=HEAD

The setDeadband is not made public, I don't know why. we just copied the code as a newGyro.java class in our project and made it public. It seems to work fine so far. You will lose a little accuracy with a larger deadband, but if it is small, it most likely won't be a problem.

Hope this helps,

Lennie

[Mike Bortfeldt]

Originally Posted by GeeTwo

... While we will look at the suggestions there, there's the possibility of using an arduino to turn the I²C gyro into a rotation encoder, or just buying an integrated solution. The NavX would also be under consideration if it were actually available.

Gus,

If you are looking for a replacement for the old KOP gyro, either the EVAL-ADXRS642Z or the EVAL-ADXRS652Z should work. Both are 0-5v analog gyros and should be a fairly easy replacement for what you are used to. In the past, I've also used an Arduino to do the integration of the gyro rate signal for both analog and SPI gyros - so that is a valid option as well.

Mike

[GeeTwo]

Originally Posted by Mike Bortfeldt

Gus,

If you are looking for a replacement for the old KOP gyro, either the EVAL-ADXRS642Z or the EVAL-ADXRS652Z should work. Both are 0-5v analog gyros and should be a fairly easy replacement for what you are used to. In the past, I've also used an Arduino to do the integration of the gyro rate signal for both analog and SPI gyros - so that is a valid option as well.

Mike

Five thousand dollars for a minimum order of 100? Or is there someone who has them for retail? Actually, even if there is, I'd rather go with the integrated all-axes solution with built-in integration and Kalman filtering at $130 than a single axis analog gyro at $50.

[Mike Bortfeldt]

Gus,

The EVAL parts can be ordered singularly at $50 or $70 depending on the model. Look near the bottom of the web page.

Mike