PWM Shield custom 20k frequency ?

Hi all!

I want to know whether it is possible to run the PWM shield on 20.000hz, thus driving dc motors that aren’t audibly resonating.

My goal is to use pwm to drive 8 dc motors, with a decent resolution (20-50steps).

Right now my Duemillanova runs a 20k frequency through pwm pins 9 and 10 (using timer 1)

Hope anyone knows if the pwm shield would be any good, and if not, whether another solution comes to your mind!

Thanks a lot.

What PWM shield? Link please.

My goal is to use pwm to drive 8 dc motors, with a decent resolution (20-50steps).

DC motors are not stepping motors.
20-50steps per what?

Hi!

Grumpy_Mike:
What PWM shield? Link please.

I was thinking the one from Sparkfun, but if you would know something more suitable, please.
http://www.sparkfun.com/short/10615

My goal is to use pwm to drive 8 dc motors, with a decent resolution (20-50steps).

DC motors are not stepping motors.
20-50steps per what?

I’m not talking about steps, but resolution <-> duty cycle on those frequencies.

That board will give you 4095 steps.
However due to the chip it uses it is not easy to change the frequency. It was designed for
LEDs any that is way faster than an LED needs so I think the answer is no.

Thanks for your answer,

Any clue what could provide 8 PWM outputs on 20.000 hz frequency?

A very quick look shows this might do what you want.
http://uk.farnell.com/analog-devices/adum4070ariz/pwm-cntrl-isolated-24v-1mhz-16soic/dp/2254949?in_merch=New%20Products&in_merch=Featured%20New%20Products&MER=i-9b10-00001144