Five bucks will buy you a STRÅLA lamp from Ikea. It’s a battery operated hanging lamp that pipes the light out through multiple branches of fiber optic bundles. But you’ll only get white out of this, which is pretty boring. [Boris] decided to swap out the stock LED for an RGB unit and drive it with an Arduino.
The lamp nucleus is just a couple of pieces of plastic which can be popped apart to reveal the shard of PCB hosting one LED. The body of that diode is flat on the top, and [Boris] filed down his replacement to match the form factor. There are only two conductors in the wire that runs between that PCB and the battery pack, so he replaced them with four conductors (R,G,B, and GND). His prototype uses the Arduino’s PWM capabilities to control the colors, but [Boris] recommends transitioning to a simple chip like a PIC 12F675 or one of the smaller ATtiny microcontrollers after you’ve got the bugs worked out.
See how this turned out in the clip after the break.