To determine the effect of gravity, orient any given axis upwards, then turn the device over, and divide the difference in readings by two. For example, if +Z reads 80, and -Z (180 degrees from first position) reads 60, the difference is 20, so 2g causes a Δ reading of 20 counts, so 1g is 10 counts.
To determine the effect of gravity, orient any given axis upwards, then turn the device over, and divide the difference in readings by two. For example, if +Z reads 80, and -Z (180 degrees from first position) reads 60, the difference is 20, so 2g causes a Δ reading of 20 counts, so 1g is 10 counts.
I am convinced that bit is wrong now. This is the graph that I get when I rotate the watch when its laying face side down. No change on X, Y or Z at all!
Clearly I have misunderstood what I need to do to get a rotation vector from the sampled data.
I realise now that because gravity is only acting on one axis, I will only see 1 on that axis and 0 on the rest... so what do I need to do to get the tilt?