I used a 3 pins on a disk gimbal mounted tester. The tester used an analog to digital converter to measure the change in velocity after making contact. Friction is a linear function coefficient.

Since other details are not given, to find the static coefficient of friction, the angle of repose concept can be applied.

For small particulate bodies, the lean angle can be applied. However, I don't think it's possible in moving rigid systems.

It depends on the purpose of your experiments. There are several ways, but they all have common elements. You have to fix one of the friction surfaces to a moving element (usually a disc or a swinging table) and the other to a fixed force sensor. Record the force signal parallel to the fixed surface using a datalogger. Taking into account the normal load on the fixed surface and the force signal, the coefficient of friction can be calculated. Examples of typical configurations are pin-on-disc, ball-on-disc and reciprocating.