You really can't use a speed controller as you need to adjust the speed as the resist spreads out and the only to do that is by eyeball.
There are just too many variables to make it automatic. The momentary on/off button works very well and it follows the KISS principal.
Craig
--- In Homebrew_PCBs@yahoogroups.com, "James" <jamesrsweet@...> wrote:
>
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "designer_craig" <cs6061@> wrote:
> >
> > Baxter,
> > Not sure what RPM the motor is running but its fairly fast. I control the speed by modulating the power button with my finger. Guess I need to figure out how to measure it.
> >
> >
>
>
> The DC fan motors can be controlled with a simple PWM circuit, 555 driving a mosfet or transistor will do the job.
>
> The shaded pole motors in AC powered fans will usually work on a light dimmer to vary the speed.
>
> Either way the actual RPM is not really important, you can just experiment with speed until the results are satisfactory.
>