This was a small project I did in my spare time after having work pay $3800 for a custom LED vision backlight. My first foray into PCB design. I worked with EAGLE to crate the circuit and board design then used http://oshpark.com/ to build three of the boards.
Started with a simple series wired LED circuit on a breadboard. Got a little fancy with some arduino PWM dimming.
I then moved on to the circuit board design. I knew I wanted transistor control on a per board level and also wanted an easy way to interconnect boards for expandability.
The 5 holes on the edges are for right angle pins and sockets. This way the boards can be connected edge to edge easily. They all share common 24v, GND and PNP trigger bus lines.
Then I got bored one night and played around with my LEAP motion. It was a good night. haha.