NEMA 17 Stepper Motor with Arduino Attempting 270 RPM with Speed Changes Compass Motor

We are still finding our way around using a stepper motor. We can get it to accelerate in 5 RPM jumps to over 500 RPM with a load but we can't get it to slow and speed up enough to overcome the demands of our compass magnet motor and make that go faster than 260 RPM.

The strategy here is that when the LDRs pass the lamp they turn the stepper motor at the present RPM (it is slowly increasing) and then after about a turn of 110 degrees the stepper motor slows down about 6 RPM and repeats this each LDR passes the lamp.

Stay tuned:)