CPU fan LED

[JCobra14]

how difficult would it be to set up a LED on your case to show your CPU fan is running... i really havent thought too much about it, but it couldnt be too terribly hard....

 

[Swanny]

Well, presumable your CPU fan will be running the whole time your computer is on, so you can just look at the power LED

 

[sohcrates]

The problem with this is that just because a fan is getting +12 volts , doesn't mean that it's actually on. So if you wired the LED in series with the fan, it would always stay on, whether the fan was actually running or not.

 

[JCobra14]

I was thinking you could put a switch on the ground side of the fan that would turn on a 5v circuit with an LED.

I dunno the electrical characteristics of a dead fan tho, that's kinda what i'm trying to figure out.



even tho I know the power LED is a practical thing, I'd like to do the CPU LED as a fun thing.

 

[Mark R]

Connect it to the speed sense wire from the fan, and it will flash at a rate determined by fan speed. Only problem with this is that it could conceivably get stuck on if the fan jams at the right position.

If you want to do it properly, you'll need a non-retriggerable monostable before the LED.