Hacking old 5 1/4" Floppy drive servo (spindle) mot

[Raydel]

Does anyone know how to modify old floppy "disk" drive motors to make the speed variable? These motors usually run at 300 RPM, I would like to be able to infinitely vary the speed between say 150 and 300 RPM. Can this be done without building complex circuitry? If you have done this, what make of drive is the easiest to modify?<p>Any and all help is much appreciated.<p>Cheers,
Raydel

[MarcMiller]

I would either pulse the motor_on pin on the floppy or tie it high and use an H-Bridge to pulse the 12V power. That should give you variable speed depending on the pulse width.