SPCR

Are there any simple/cheap fan controllers that supply 12V at power on for a second or two, then switch to the selected voltage?

Since that's a question of automation, I doubt simple and cheap come into the equation. I haven't seen any in all this time at least.

Only controller of the dozen I've used that did that was the BigNG, but that one is expensive and complicated. Beyond that, I think one of the programmable 5.25" bay units might, but I haven't looked.

that's a really strange request. I am trying to envision a need for that.

I can't. why do you need it?

I have the same interest for use running a fan at 5V where its startup voltage may be higher, say 7V. I couldnt find evidence of anyone using a high spin-up voltage circuit/controller, although now that I think about it, I think some of my past motherboards initially start all fans at 12V, then throttle down.

i think a 555 timer circuit might be wired to accomplish a voltage delay.

here's another thread seeming to have similar question as Luke, but no solution found yet: viewtopic.php?t=59664

~El~Jefe~ wrote:that's a really strange request. I am trying to envision a need for that.

I can't. why do you need it?

If you're using a fan with extreme undervolting, down to 4V say, then the fan may not spin up, even though it runs just fine at 4V. So every time you power cycle the system, you have to remember to fiddle with the control - not very user friendly.

Hardware-wise, all you need is a timer that triggers at power up, and switches to full voltage and back. Maybe $0.25 of parts?

Jadukey wrote:i think a 555 timer circuit might be wired to accomplish a voltage delay.

Another way would be to use a very simple 8-pin microcontroller.

Ah. well, in the time it took to find SPCR and type this all and reply....

hm that would be like at least 6 minutes if you count registration and then looking at replies/checking etc.

if you have a 3.5" rheobus controller, 4 knobs, it would take about 2.5-3 seconds to flick them to right, and about 1.5 to 2.5 seconds to turn them back down to the left. Your hand would be on them so it would cut down on time.

so, yeah.

That's like 65 days worth of solving this issue if you figure a maximum of 5.5 seconds per turn on and 5 volt to 12volt to 5 volt adjustments.

CUrrently, if you chose to not read this post, you would have saved 9 days worth of turning on and turning off, maybe 11.

yeah.

I've heard that a capacitor can do that too. But i dont know for shure.

automatically switches from 12V to 4.3V after about 2 second delay. Not very clean, but seems to work fine.

The NoiseMagic NMT-2 and NMT-3 controllers do this. They start the fan at 12V, then reduce the voltage based on ambient temperature. I've used NMT-3 controllers for years with no problems.

Ok, I have a fan controller with 12 volt spin up but however it doesnt go down super low, only like to 6's volt wise it seems.

http://www.aerocool.us/peripheral/f6xt.htm

that one, which I have, is really great. However, it doesnt go down low enough for my overly powered fans. I wish I had the cash to drop on 4 new fans of a lower rpm, it would be more useful. I suspect everyone on here has slower moving fans than I currently do. If so, the F6XT is the thing you want. IT remembers your past settings and first bursts to 12volts for like 2 seconds.