I build this with my "science fair 200", combined with a stepper I retrieved from a scanner. The simulation doesn't work (even with the coils detached), it ends with a 'no solution' error, so I guess my circuit isn't completely sound, but the real circuit works. I can control the speed of the stepper with the pot. Seeing the simulation of what happens, I suppose I should not tie the stepper directly to the same wires as the led without some protection in between ?
