We're using the accelerometer and gyroscope data streamed from MetaWear C devices for analysis by our algorithms. We've noticed that the accelerometers do not seem to be very accurate. I would expect the magnitude of the accelerometer reading to be around 9.8 m/s^2 regardless of the orientation, but in fact the magnitude does vary pretty significantly. I measured it along each of 6 directions (+/- x, y, z) with the device stationary for 2 devices, and found magnitudes as low as 8.3 and as high as 11.5.
Is this what you would expect for all the MetaWear devices? Or do some of them use more accurate accelerometer hardware?