Ok..I'll study first..but anyway I was digging through my old bookmarks, seems I don't have to design the circuit at all..

http://www.rmcybernetics.com/projects/DIY_..._controller.htm

All the parts wil only come up to a few ringgit, only one I've never bought before is the power MOSFET, but I guess it won't really cost that much. Also has other interesting DIY project..tesla coils, pulse jets, ect.. DIY also means do-at-your-own-risk..some of those projects are not play play.

Hmm, maybe after exams I should do a bulk on this? Sell PWM components/finished PWM units.. Going out of university for haircut tomorrow or so, can pick up components for a quick try on a prototyping board. Won't be able to install in my PC, but at least will have proof of concept.

So...

So...

Can you do it?

Can you do it?

where cna i get nice grills?? cause my fans are so naked now

Try searching in the bulk/garage sales, quite a few people selling.

However if you're in this thread because of the title, then I should warn you that putting cool looking fan grilles will usually obstruct airflow especially for high cfm fans. Also will make the fan even louder..

I'll give it a shot, probably this weekend I'll get back to you, hopefully end of this month I can figure out how to make enough to sell . Should be quite cheap, probably way below RM100 for a multi fan control. Thinking of a way to make system monitors also (rpm, temp, voltage), already know how to make the circuit, just a matter of trying out & improving the circuit for better accuracy.

Multi fan controller?
I just want a fan controller to be used for one fan only...

lohwenli, i was wondering something...bout the VR controller, not the PWM controller.

Assuming we are using a low current dc fan..say <1.0A. We are able to put the potentiometer in series wif the load (fan), and by doing this,we can vary the current across the load and current through it. What if i want to control the current through the fan only, while maintaining the voltage across it? Will connecting the potentiometer in parallel with the load simply be able to do it?

Edit: Did some calculations and found out that it cant be done..nvm then.

This post has been edited by x800: Oct 4 2006, 08:40 PM

Not Bad...

The Circuit is simple, but for a fan controller ... erm...

maybe if u have a powerfull fan to control id say this is the circuit.

i have built a few Fan controllers and so far this one is the one with the most components

Will Give it a whack after i finish my assembling my current fan controller.

Shawty,

maybe i will try the fan controller on the nidec first and give u the feedback ya !!!

*deleted*

misunderstanding..

This post has been edited by x800: Oct 4 2006, 08:39 PM

What the heck you guys are discussing here?

I can't understand even a bit...

forget what i posted earlier shawty..i had a little misunderstanding of the concept..

Erk?
Why did u delete that post?

I didn't understand then let it be la...

Just go on you guys discuss those things...
I'll just wait for the final product leh...

i deleted it not bcoz of u leh..its bcoz i'll look silly if other knowledgable ppl read that..coz i wanted to make sumthing that is quite impossible w/o using PWM.. eh u oso delete ur quote lar..

Hmm, let me recall..what happens when fans run is that as the fan spins faster there will be an increasing reverse voltage across it (back emf if you want to be technical), it will seem like a voltage drop across the fan but actually the voltage drop is very small, most of the 12V across the fan is made up by the reverse voltage rather than the voltage drop. When the fan is not spinning there is no reverse voltage and the fan actually has little resistance causing a big current to flow until the fan spins up and the reverse voltage causes current to drop (block a fan/motor from spinning for long enough & you'll see it smoking because of this). Rated current is for when the fan has reached its operation rpm.

Looks like I forgot to take that into account..if the initial current is too small because the total resistance of the fan & VR is too high, the fan won't start at all, and if the initial current is beyond the capability of the VR to handle because the fan & VR resistance is too low then well the VR is history. Means I'm still not too far off the mark, so to clear things I took out my prototype board and hooked up 4 of my fans (low power ~0.5A) to a 200 ohm VR in series..it WORKED! Managed to control fan voltage from 11.9V to 4V, so can still be used for the lower power fans, but higher power fans would have no choice but to use PWM (the VR did get a wee bit warm even on 0.5A).

Oh btw sHawTY, the circuit only looks complicated, but can easily fit into a matchbox. I should be able to build a few prototypes in a week or 2 after my tests these few weeks, sell you the first 1 cheap . What's left is to try out the design first, but I have no doubt there should be not much problems getting it to work. Later I can give multi fan controllers & sensors a shot.

VR in parallel? Now that would be a really quick way to roast a VR..turn to minimum, 0.1 ohm, get 120A current on 12V equals 1440W output..if your psu doesn't blow, congrats..pls recommend the brand to the rest of us..

yeah, realised that already.and btw, thx for the info bout the reverse voltage thingy.u reminded me what my lecturer taught me last sem

This post has been edited by x800: Oct 5 2006, 05:53 PM

hey..how about my CM XDream III???
any idea how to increase the speed from 2k to 6k???
i dont care the noise anymore..
my case is sound proof


This post has been edited by xen0: Oct 5 2006, 09:49 PM

there's always the delta tornado killers which spins at 6000rpm, and creating hell lot of a noise, but great cfm!

Change the fan to Delta Focusflow...

i did this mod also. and it works.

bit i suggest that u connect the fan not directly to the psu, but to a male molex, then u plug it to the female molex from the PSU.

and for the variable fan controller, just add a variable resistor. if you want you can also add transistor and capacitors, but that one i really dunno how to design the circuit. dun ask me

for smart fan, i dunno how to do it... lolz (erm.... if u leave the fan as it is and dun mod it, the mobo can control the fan speed aka smart fan)

Got all the stuff to built the PWM controller..hehe..stay tuned..also some stuff to build a PSU tester/loader..

Sorry it took a while, and sorry for such a short post (may consider I'm spamming, but in a hurry-PC down, so have to go CC)

We're waiting for the results...