Few months ago I used some RGB LED lighting in my room (eBay China special). The setup uses an IR remote control and a control box to control the lighting. Power is supplied via a high current 12V power supply (10A supply)
So, I decided to modify the fans to sync the colors of the fans with the rest of lighting. I already had tons of RGB LED’s, so it was really a matter of A LOT of soldering. One thing to note is that the LED ligthing system uses common Anode configuration, with a single 12V rail and 3 (RGB) grounds.
A quick application of a soldering iron and all the LED leads have been removed. Since the LEDs are no longer supplied with fan voltage rail, the brightness of the LEDs will no longer be tied to the speed of the fans.
All LEDs were connected via point-to-point connections. This was actually a fair bit of work. The ribbon cable is quite delicate so I had to take extra care when stripping the wire ends as not to cut the lead.
The ribbon cable is nice and flat so it doesn’t affect the overall diameter of the fan much. Still, there would be certain configuration where the fans are too close to an edge where this would be problematic. Fortunately in my case, the fans are spaced sufficiently apart that the ribbon cable doesn’t interfere.
Once all the LEDs were electrically connected they had to be terminated via current limiting resistors. During bench testing I found that the 470ohm resistors provided the best brightness to current ratio at 12V. Since the LED receives power on a common Anode and each color draws slightly different amount of current, it’s important to place the resistors on the individual color leads. Putting the resistor on the anode pin will not work properly when using more than one color at a time.
To connect the fans to the LED strip I bought some JST 4 pin connectors. It’s surprisingly difficult to find small 4 pin connectors locally, so I had to do another China eBay order and wait another month for them to show up.
To connect all the fans together and to connect them to the LED strip I braided few 24 gauge wires to make a nice flat cable. This cable will run outside of the computer via a hole (meant for water cooling hose) in the computer case.
Once all the fans were soldered up, I installed them back into the computer. My wire organization skills are certainly not the best, but then again this is just a Mini ATX case so not heck a lot of room to stash the cabling.
Here’s a short video of the LED system, with the light mode set to cycle all colors.