MPU-6050 accelerometer , sample rate ideas requested

Hi all,

I'm looking for a solution to balance propellers and wheels and inspired by the following example:

Youtube dynamic propeller balancer

For this I would need to sample every "degree" of the propeller or wheel which isn't very complicated in essence. An optical sensor will be used to determine the absolute position at every revolution, the accelerometer will measure the imbalance.

What makes it complicated it the speed of the propeller or wheel which needs to be measured, which will be between 1000 and 3000 rpm.
I would like to use the MPU-6050 accelerometer which has a sample rate of 1kHz.

My question is how this can be done. At 3000rpm (50rps) I would need to sample at 18kHz (50rps x 360 degrees) which is beyond the sensor specification.

All ideas are welcome :slight_smile:

For this I would need to sample every "degree" of the propeller or wheel which isn't very complicated in essence.

Who told you that you need to get a acceleration reading for every degree the propeller turns?

What makes it complicated it the speed of the propeller or wheel which needs to be measured, which will be between 1000 and 3000 rpm.

Where are these numbers from? Why can't you just turn the propeller slower to measure the imbalance? The imbalance is constant and does not depend on the rotation speed. You can detect it while turning slower than usual.

I've used the propeller as an example but would actually like to sample (car)wheel imbalance. Vibrations often can be felt at a certain speed only.

I had the idea to sample 0, 10, 20, .... in the first rotation cycle, 1, 11, 21, .... in the second rotation cycle, and continue till every degree has been sampled.

However, I'm not sure if this is going to work and wonder whether there're other possibilities.

Vibrations often can be felt at a certain speed only.

But they should be measurable at lower speed too. That's the reason you use a sensor and not put your hand on the axis.

However, I'm not sure if this is going to work and wonder whether there're other possibilities.

Sure it does but you need a signal when the wheel is at a "zero" position. By counting the time between two signals you know how fast it turns and you can measure at the exact time when you need it.

What sort of "car wheel" will be turning at 1000 to 3000 RPM?

1000 RPM on a typical passenger vehicle would be over 80 mph or 130 km/h.