I need to measure the torque of some small stepper motors (NEMA 17 and 23) when run from one of my boards. I don't need absolute values so the 'string and weight around a pulley' is over the top; I need a more compact solution to do relative measurements and characterise the drive waveforms.
I was thing about coupling a stepper motor to a DC motor and feeding the DC motor to something like a constant current load. Memories of DC dynamos on my bike suggest this will work. However, when reading up on Dynamometers it seems like the actually feed the motor from a drive rather than just absorb the generated current.
Instead of a DC motor I also thought about using another stepper as the generator.