I have a problem that I need to measure an RPM of a rotating axle with a single element (circuit) attached to it - i.e. I can't use a hall effect sensor, because I can't use a separate magnet - I can only use what's mounter on the axle. The axle will rotate only on one axis - but that could be X, Y or Z. So the solution should be modular in that regard. I'm looking to measure up to 150 RPM most, and I'm using an Arduino for the readings.
I was thinking of using an accelerometer, a gyro or a compass. Compass feels like it would fill the bill best, but I'm not sure it would work properly on every axis, not just Z?
What would be the best component and implementation strategy for a solution to such a problem?
Thanks for the "-1"s, here are the clarifications:
- A single element as in one part product - for hall effect we'll need two parts - the sensor and the magnet. So the whole end product should be a single element.
- An axle can rotate only on one axis, but it could be initially placed on different angles - so the same circuit should work for any kind of setup (any axis).
- The speed information will be collected on the rotating part.