WillysNut, here's a couple for you.

[stool]

WillysNut, here's a couple for you-fan controls

Found these today searching around. Both very effective and very cheap.

Fan control

and
Temp. fan control

 

[WillysNut]

I like the idea of integrating temp control into this setup. Have you played around with that one at all? The first link seems to be a nice little unit but suffer's from the same voltage drop that most LM317 setups have. Very compact though...I can picture using it for a couple of smaller HDD bay fans or something similar. Thanks for the links stool!

 

[stool]

I just ordered the parts, and I'll probably try it out next week.

The first one seems to indicate that with using transistors, the drop is much less severe. I'm going to try that one too.

 

[Burner]

Hi Guy's,
Just wanted to let you know I've built the Temp fan control not long after it was posted on the site linked to, Mainly for a 120mm Sunon intake fan, the circuit has been working ok so far. Wanted to share what I've found so far,The one thing I don't like is the fact it's touchy to adjust, mainly setting a start voltage for the fan, depending on case and ambient temps, and thermistor placement. What's happening is the fan labor's to start when the ambient temp is lower (furnance not running) due to the thermistor controlling the voltage, causing the circuit to heat up some, once thing's heat up inside the case it's ok. I do know that to much or not enough voltage can cause excessive heat and premature failure. I'm not that keen with electronic circuits, still learning. Would it be possible to limit the low end or start voltage to 5 volt minimum to reduce this? I believe the sampling rate of the thermistor is 5 seconds, would using a faster sampling rate thermistor help? I've been following your threads on this subject with a great interest, finally feel I've something to contribute. Looking foward to hear more on this subject.
Burner

 

[stool]

I'm in the same boats as you are. I'm trying to learn this stuff myself. For me, the easiest way is just trial and error, and doing hands-on assemblies.

When I get the parts, I'll start messing with both, and see what the results are.