USB Motor Speed control..

how easy/tricky is it to build a USB device that can control a motor speed?
Just a smal electric motor that needs to ramp between a few different RPMs,
no specific precision required..; just needs to be able to start/stop the
motor, and change its speeds to a few different preset levels ..

I'm presuming that driver interface would be the harder of the 2 parts of
dev (driver and hardware) .. What kind of hardware is best used to design a
circuit like this?

Any pointers for pre-made circuits like this?

Thanks in advance!

"Lord-Data" <(E-Mail Removed)> wrote in message
news:43197344$0$15502$(E-Mail Removed)...
> how easy/tricky is it to build a USB device that can control a motor
speed?
> Just a smal electric motor that needs to ramp between a few different
RPMs,
> no specific precision required..; just needs to be able to start/stop the
> motor, and change its speeds to a few different preset levels ..
>
> I'm presuming that driver interface would be the harder of the 2 parts of
> dev (driver and hardware) .. What kind of hardware is best used to design
a
> circuit like this?
>
> Any pointers for pre-made circuits like this?
>
> Thanks in advance!
>
>
This may be fairly definitive for you:
http://www.eletrica.ufpr.br/lamar/Pr...eport_2002.pdf

Cheers.

Ken