Gyro Repeatability, Expected Drift ?

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1) Does anyone know what gyros were in previous First kits (or how to interpret the printing on the gyro case) ? I'm using one mounted on a dark green PCB for testing. (FIRST: Please consider printing the year on the PCB & the gyro part number too!).

2) I'm using KWs gyro code and have read everything I can find. I have the gyro mounted on a wooden board with a compass rose on it. The chip is accurately mounted in the center with a pointer. After calibration, it largely seems to work. I can rotate it 180 degrees (fairly slowly) and get pretty close to 180 reported (actually 1800). But many times when I return it to zero, it will be 5-10 degrees off in either direction and from then on everything is off. Any idea how repeatable measurements should be on a desk ? on a robot (with all its vibration etc) ? Any suggestions ? Since I don't know what the chip is, the software is currently set to a adxrs150.

There is significant evidence that the max rate the gyro can turn must be fairly slow else the reported numbers will be way off. But even when I rotate it slowly, its repeatability can be off by 5% or more. Is that normal ?