Hi,steve:
Thank your suggestion. There is surely a gearbox in my design. But i need the motor's velocity is from 5 RPM to 8000RPM(the maximum speed when no load).This requirement is necessary.
Otherwise,I must change the motor to stepper-motor or others.That will increase the cost.
And another important reason that I want use the toy-motor,is I have known
that others have complete the same job and it motor can working in the low speed.So I think we can do it too.
Can you help me?

Sum Zhang