I’m working on a project that uses the AltIMU-10 v3 to provide orientation data for an AHRS. I’ve put together a very basic sketch that outputs the various values from the sensor and I’ve noticed that the gyro settles at 0 on the X and Z axis, but the Y axis always shows a large negative value. Here’s short section of the output:

{“heading”: 178.44, “magX”: -2533, “maxY”: 77, “magZ”: -2420, “accX”: -438, “accY”: -54, “accZ”: 16829, “gyroX”: 0, “gyroY”: -15602, “gyroZ”: 0}

{“heading”: 178.29, “magX”: -2528, “maxY”: 84, “magZ”: -2410, “accX”: -473, “accY”: -54, “accZ”: 16811, “gyroX”: 0, “gyroY”: -15595, “gyroZ”: 0}

{“heading”: 178.45, “magX”: -2536, “maxY”: 84, “magZ”: -2420, “accX”: -470, “accY”: -102, “accZ”: 16816, “gyroX”: 0, “gyroY”: -15591, “gyroZ”: 0}

{“heading”: 178.38, “magX”: -2534, “maxY”: 78, “magZ”: -2417, “accX”: -406, “accY”: -40, “accZ”: 16790, “gyroX”: 0, “gyroY”: -15602, “gyroZ”: 0}

{“heading”: 178.52, “magX”: -2522, “maxY”: 79, “magZ”: -2419, “accX”: -462, “accY”: -94, “accZ”: 16929, “gyroX”: 0, “gyroY”: -15597, “gyroZ”: 0}

{“heading”: 178.59, “magX”: -2538, “maxY”: 72, “magZ”: -2424, “accX”: -405, “accY”: -64, “accZ”: 16786, “gyroX”: 0, “gyroY”: -15590, “gyroZ”: 0}

{“heading”: 178.46, “magX”: -2531, “maxY”: 79, “magZ”: -2431, “accX”: -367, “accY”: -75, “accZ”: 16844, “gyroX”: 0, “gyroY”: -15605, “gyroZ”: 0}

{“heading”: 178.42, “magX”: -2531, “maxY”: 79, “magZ”: -2410, “accX”: -437, “accY”: -61, “accZ”: 16844, “gyroX”: 0, “gyroY”: -15590, “gyroZ”: 0}

{“heading”: 178.91, “magX”: -2538, “maxY”: 68, “magZ”: -2423, “accX”: -443, “accY”: -136, “accZ”: 16826, “gyroX”: 0, “gyroY”: -15589, “gyroZ”: 0}

{“heading”: 178.39, “magX”: -2530, “maxY”: 80, “magZ”: -2421, “accX”: -407, “accY”: -60, “accZ”: 16836, “gyroX”: 0, “gyroY”: -15605, “gyroZ”: 0}

{“heading”: 178.52, “magX”: -2529, “maxY”: 79, “magZ”: -2416, “accX”: -414, “accY”: -95, “accZ”: 16851, “gyroX”: 0, “gyroY”: -15599, “gyroZ”: 0}

I’m expect the accelerometer to show a constant gravitational acceleration, but I’m curious what the constant value on the gyro’s Y axis means. I’ve tried this on both of the AltiIMU-10 v3s and also on a MinIMU-9 v2 that I had and it seems to be consistent. If this is something obvious, please forgive my ignorance.

Cheers,

Steve