Hi Folks, I am going to be moving on to watercooling so all the 3 pin fan headers on my mb will be free. So i was wondering if I could could connect LEDs to the 3 pin fan headers. I think that this would be cool as i could use Gigabytes software to switch them on once the cpu gets to a certian temp. Hopefully I will also be moving on to a full cover GPU block too and I thought that it may be possible to connect a LED to the 2 pin fan header on the GPU. I have looked at pre wired LEDs that are avaible, and i didnt motice a resistor. One for all yhou electronics guys, will i need one? Also, can you forsee any other issue i may have with this idea? thanks
You'd need a 12v pre-wired LED to connect to the motherboard connectors or wire the LEDs yourself with resisitors appropriate for the LEDs and their forward voltages. A motherboard header will provide power for dozens of LEDs if you wire them correctly. A GPU fan connector is much the same as a motherboard header but may not provide the 1 Amp that a mobo will provide. The only thing I would say is be careful when wiring stuff up to your motherboard as if you were to short the pins things may not go too well. I'd be more inclined to wire them up to a Molex connector. If you make a mess of the wiring a short would just trip your PSUs safety features.
Mobos vary in the Amps that their fan headers put out. Check it out first with a multimeter --don't overload them. Some also have RPM monitors on the third line which you may need to disable in BIOS else the mobo thinks the absent fan has failed and will panic. I used the third line for pulse-monitoring a flowmeter instead. If the mobo uses any form of fan speed throttling again you may need to disable it in BIOS.
Hey Thanks for the advice. I have been having a look around and I have found aquatuening do a LED with the correct resistor. I plan to connect about 12-15 of them in paraell off 1 fan header. I will check the amps and there are 4 headers so I can use those if needs be but hopefully I will get away with 1 header. I have also had a look at the bios and I can change the headers from PWM to voltage control. I can't wait!
You should be fine to run 15 leds from one mobo fan header.... assuming that your mobo fan headers can support 1a+ (rtfm) and assuming that the leds are average ones, as in 50ma or less=750ma or less total load, not the mega power hungry ones I wouldn't buy 15 pre-wired leds, i'd just get one led for now, and a few resistors, so you can experiment with the results. You could have the mobo header run in pwm mode, that way the led will gradually turn on, from dim to bright, as the temp rises. Or if you want them to stay off for much longer until they turn on, then use voltage control. Either way, experimentation will tell you what value resistor gives the desired effect. I do think it's a shame to hook up leds this way however... as the only time the pc will be lit up, is if it ever overheats Why not hook up the leds to 12v, and run the radiator fans from the mobo headers, so if stuff overheats, the fans spin faster
