I'd like to power a bright LED (1W or 3W) connecting it onto a power source of my computer, directly on the motherboard. I think about using either a fan connector or directly the ATX Power supply. But I don't find any information about how to do that well on the net.
I will have to use a resistance, a led, some wires and perhaps a power switch, and probably some cooling stiff for the LED and the resistance. But what about what-to-do and what-not-to-do about such a DIY stuff ? I mean, what may I connect onto what, what must I take care about, … ?
examples : the fan connector has 3 pins. My LED has 2 pins…
Making such a connection may damage the motherboard ? What may I do to prevent this ? What about the voltages and power ?
I was starting this with confidence, but not finding anyone that talks about that on the net makes me a litlle be scared.
Best Answer
There is nothing special about a computer when it comes to leds. You can power directly off the ATX supply (Either 12V, 5V, 3.3V) or from the fan connector (12V). Just add an appropriate resistor and you are done. You need to apply the same led calculations as anything else:
$$Resistance = \frac{Source\,Voltage - LED\,Forward\,Voltage\,Drop}{Desired\,Current}$$
The Fan connectors have three pins, one for 12v, one for Ground, and one for Tach/Speed Sensing.
Since you mentioned cooling, are you talking about 1W or higher LEDs? The same still applies. You could use the fan connector for both a cooling fan, as well as the led power source.