fan controlers

[satanicoo]

i have a fan thats still a bit noisy with 7 volt.

with 5 it wont spin up.

is there a way to build a fan controler that instead ov voltage, it controls the rpm? would it be hard?

my idea is: build a circuit that sends impulses of 12 volts, so that it starts up, but never reaches high speeds, because they are only impulses.

[Khledar]

If you're going to build a circuit why not just build one that gives you about 6V ? Worried that's still too much?

[BrianW]

You will have to look, but there is already a circuit that does that. I believe some of the LCD's that have fan controllers have em. I'll look around when I get home from work.

You could always go with a Rheobus (I think they go as low as 5 volts, not sure though)

BrianW

[redleader]

SVC sells some nice ones. I bought the Zalman baybus, but I'd probably get the Vantec instead.

[punish3r]

my idea is: build a circuit that sends impulses of 12 volts, so that it starts up, but never reaches high speeds, because they are only impulses.

You're talking about a PWM (Pulse Width Modulation) controller. Hell, I've built a PWM out of a LM339 and a few discrete components I had in my "Misc." box before. Wasn't able to provide much power, but it worked for what I needed it for. Now, if you're looking for something to sink a bit more power (like 3-12A@12VDC) for a larger fan, or group of fans, UTFSE and search for G. Forrest Cook. He did a decent 12/24VDC PWM for Home Power Magazine a couple of years ago, and I'm sure someone has the schematic online by now.

Update:
Found the article here (http://www.solorb.com/elect/solarcirc/pwm1/) enjoy

[Cyco-Dude]

its true that fans often wont start up on 5 volts, but once they are started they will run on 5 volts. start em on 12, then dail them down to 5.

also, procooling just posted a preview of a PWM fan controller that you can read here (http://www.procooling.com/reviews/html/aardil_s_pwm_fan_controller.php) if you havent already.

[Aardil]

In referance to my PWM controller, that was the problem we found with the first proto type, it wouldnt start several models of fans. This was fixed in the final prototype and in in the production model. The problem was not all fans like PWM stutter voltage some took over 9 volts to get them going then you could throttle them back to around 5 volts. My circuit buffers the PWM spikes so that the signal is alot smoother and the fans will start at lower voltage without the normal PWM stutter.
Just food for thought
Aardil

[Celestial_fury]

I bought this:
http://www.coolputer.fi/tuotekuvat/61.jpg
I got it from www.coolputer.fi/
under the modding section there are 4 items called 'Speedlimit' for 2 or 4 fans. The Speedlimit 4 (LOPPU) is a kit with all components and a PCB for you to solder together (thats the one I bought). The non-LOPPU version is pre-built and costs twice as much.
They do world wide shipping.
What I like about it is that on Booting the pc, the fans run on full voltage for a couple of seconds, then throttle back to whatever setting you have on the Pots. You can also fine-tune the pots so that they wont dial down below a minimum voltage.
I currently run the following config:

POT 1: CPU Fan Coolermaster HHC-001 - 7000RPM Max (rpm monitoring still attatched to MOBO)
POT 2: 120mm fan on side panel
POT 3: 2X 80mm intake fans
POT 4: 2x 80mm outtake fans


FuRy