How to measure the moment of resistance to rotation of the motor shaft with high resolution?

Question

Arduino

Comrades, it is required to assemble a stand on which it will be necessary to determine the coefficient of sliding friction. This requires a moment of resistance. There was an idea to put the usual DPT, but by changing the current, look at the change in the moment, and from there take the moment of resistance, but with a sliding contact it will give a lot of noise, as I think. Moreover, the change in the moment of friction will hardly reach units of N * cm. So that's a problem. Well, to shove an arduino here to control and view some characteristics, and take data.

Answer 1

You think right, but these interferences, they are treated, both in hardware and in software, which together give a good result, if it’s just for current ...
And you can also have a position sensor on the shaft, measure inertia, dose energy and feel the finer resistance. Without Durina, it definitely won't do.

Answer 2

Such a solution is also possible: they spun the shaft and wait until it stops, measuring the angle of rotation of the shaft from time to time, for example, with an encoder (with high resolution) and the same arduina (although something more serious is needed). From the resulting function, you get your dependency. The moment of inertia of the shaft can be calculated analytically if the geometry is simple or measured.