DIY Fan Controller

[floodx]

Hey, I'm interested in making my own fan controller and was looking for a little advice. I have a 92 in the back and an 80 in the front, both of which I plan on wiring up seperate. My question to you all is what I should use to control them. I'm trying to decide between using switches to change them from 12V - 7V - 5V (high, med, low), or a simply just using a rheostat. Can anyone point up any dis/advantages with each? Any suggestions to make this go easier? Thanks in advance!

 

[zagood]

Switches are effective but obviously lack any fine tuning choices.

You can find DIY rheostat instructions all over google.

If you just want an easy solution, the Sunbeam Rheobus is probably the best controller for the price - usually around $15. Plus - if you want to have some fun with it you can always switch out the knobs, replace the LEDs, put resistors on the LEDs so they're not as bright, make your own faceplate etc. They're very mod-friendly.

-z

 

[Zepper]

You'll find that rheostats to control fans that need higher power are more expensive than many fans unless you can find what you need at some of the surplus type sites or a local electronics surplus shop. The Sunbeam Rheobus mentioned above, doesn't really use passive rheostats for control, they use an inexpensive, low-power pot to control a transistor which can handle up to 18 Watts (1.5A at 12V) per channel, transistors being much less expensive than high-power capacity rheostats. I suppose you could build similar on your own easily enough (circuit diagrams can be located via your fave search engine), but I'd guess the low cost of the Sunbeam unit would argue against it. jab-tech.com and svc.com have had the Sunbeam at good prices.

.bh.

 

[Modelworks]

If you really wanted to build one yourself you can for about $3 .
You need a LM317T and a potentiometer + 2 caps, resistor. Change the value on the pot to set the voltage for the fan. Can handle 1.5A loads if you heatsink it. Could use the PC case for that.
http://www.national.com/mpf/LM/LM317.html

If you need more than 1.5A then you have to add a transistor , about $1 more.