PWM Fan Controller

[bsodmike]

I'd like to first say, wow - talk about seeing this forum for the first time, ever. And guess what, it's dead too

Considering that I’ve fitted a noisy delta ’screamer’ in my Core 2 Duo box, I decided to set about making a simple PWM signal generator based on pot position.

I ended up developing a simple circuit to take care of the loud fan, and you can see my thoughts on this in detail here.

Here are some images on my progress:







And here is the PWM signal in all it's glory, applied to the gate of a power MOSFET (IR640), as it's all I have here. You *could* use a power transistor if you wish.

(Min dutycycle)


(Max dutycycle)


For those who don't know, the duty cycle is the percentage the pulse is high for during a period, i.e. a PWM signal with 50% duty cycle would be a perfect square wave, and if the voltage is Vcc (5v), the avg voltage would of course be half that, 2.5v!

[kempez]

Good work Mike - that's impressive stuff

[chuckskull]

Kinda makes me wish I'd done something other than electocute my friends in my electronics classes in school.

Nice work, look pretty sleek too.

[bsodmike]

Thanks guys

This should provide ~7.7 - 10vdc to the fan, but I'll experiment a bit and see how it goes. what's nice is that this idea could be further extended to either use (a) a single pot to drive multiple fans or (b) have a pot per fan.

One could even throw the whole pot idea out and throw in a couple buttons, an LCD and you are left with a commercial baybus. I still like this the way it is as it *is* sleek and gets the job done. what I will do (if at all) is add a couple more PWM outputs for anyother fans that might go into the case, and have a MOSFET for each fan (obviously) with all the FETs being driven from the common PWM signal...