I have some cheap plastic gear motors, the kind with the 3mm D shape shafts. They work, and I can control them with software but they have a problem in that there is a rather high minimum speed. With low voltage (or low duty cycle PWM) the motors stall, then I raise the power and they start moving but at a speed that is close to 1/3rd the maximum speed.
I need something more controllable, that will run over a wider range of speeds, from on order 100 RPM to near zero. Do I have to use a stepper motor or can I do this by spending the $$ to get a better quality DC motor?
I guess this is a general question about how slow I can expect a DC motor to run.
I've tried using an initial voltage spike to overcome static friction then quickly ramping down to the desired speed. This only helps a little.