Gyroscope ADXRS300 of Analog Devices

[Sparks333]

I worked with a lesser model of Analog Devices gyroscope. They aren't bad, but BGAs are evil to hand-solder.

The 25 degrees C is a point of reference for the temperature output. The datasheet says that at 298K (which is 25C), the voltage output on the temperature sensor is 2.50 volts. Useful if you're looking for ultra-precise measurement.

As for calibration, the gyro module itself has no calibration capabilities other than to offset the 2.5v reference voltage (I wouldn't recommend that). If you're getting discrepancies between the axes, then I'd say make sure the voltage on the reference line has no interference - put a large capacitor in parallel with ground, or put the device on an independent circuit. If all else fails, try to calculate an optimal scale factor for your circuit - iMEMs devices, as with all sensors, have slight differences inherent in manufacturing.

Good luck

Sparks

EDIT: Keep in mind that the scale factor for one gyroscope may not work for the others on that board. Also, looking at the datasheet shows you that the temperature has an effect on the output - about 8.4 mV/K - which could account for your discrepancy.

[TubaMorg]

We used this gyro on our robot last year and it worked well for us. I have to say, though, that we didn't use an overly elaborate implementation. We just purchased the Evaluation board model and used it as is. As far as calibration went, we found the baseline for the robot at rest (1 second) then used that as a offset. As you noted though, as the gyro changes temperature, the baseline can change. We tried to make sure the temperture was stablized before going into competition. We also added a bit of code to reset the baseline when the robot is at rest (as determined by the operator). There are more sophisticated ways of accomplishing this, though. None of us are engineers, so we went with simple and expeditious. Analog devices has other information that might help you to. Check this out:

http://www.analog.com/en/prodRes/0,2...00_871,00.html

and for the Eval board:

http://www.analog.com/UploadedFiles/...XRS300EB_0.pdf