inconsequentia

Last week I bought a set of DIODER lights from the Ikea down the road, pretty much on a whim. They’re not the cheapest way to buy RGB strip light­ing, but I did like the mod­u­lar design. And it’s remark­ably easy to modify the con­trol­ler to drive the sys­tem with an arduino.

The sys­tem comes with a con­trol­ler that allows you to set a col­our manu­ally, as well as pre-set col­our change and fade func­tions. Rather than build my own cir­cuit I wanted to save time by reusing this con­trol­ler. Open­ing it up revealed a PIC micro­con­trol­ler, and three MOS­FETs for the red, green and blue channels.

First thing to do is dis­able the micro­con­trol­ler by cut­ting through the power track. Cut­ting through the big pad I’ve marked on the dia­gram means it’s easy to then wire a switch across it if you want to be able to use the con­trol­ler as normal.

Three out­put pins from the micro­con­trol­ler drive the MOS­FETs, but only two of them have big friendly solder pads, so I soldered wires on to the three res­ist­ors just below the MOS­FETs (R5, R6 AND R7). Then soldered the other ends of these wires to a short strip of header pins. These are then plugged straight in to pins 9, 10 and 11 on my Ardu­ino. I’ve labelled the pic­ture with which MOSFET drives which LED chan­nel, but they match what’s prin­ted on the PCB where the input cable is connected.

Finally, we need a ground wire. Easi­est way to con­nect it is to solder a wire on to the –ve wire on the input cable. The other end of that is again soldered on to a header pin, which is con­nec­ted to the ground pin of the Arduino.

And that’s it. I hooked these up to my LeoStick the Freet­ron­ics guys gave away as swag for LCA 2012 and loaded up some demo code I had sit­ting around from the last time I played with an RGB LED.

Right now I’m using this setup as a light con­trol­ler for bob­light on my XBMC media centre. Set­ting up the con­trol­ler, writ­ing my own single-channel bob­light sketch, installing soft­ware and con­fig­ur­ing the XBMC addon was all done in a single even­ing. It was a lot of fun, and even with a single chan­nel the res­ults are pretty awesome.