The Rainbowduino is a variant of the Arduino and among other things is capable of driving an 8x8 RGB LED matrix. I had just finished a backyard re-model and was in need of an entrance sign.

Rainbowduino Sign from opengadgets on Vimeo.

Part List:

2 Rainbowduinos - $19.90 each
2 8 x 8 Matrix LEDs - $18.50 each
6V Power Supply - $4.90
UartSBee - $19.50
DC Jack to JST Pin Converter - $.80
Piece of Wood for the Sign

Step 1: Carving and Painting the Sign

I had recently acquired a CarveWright CNC wood carving machine. It's a pretty nice piece of equipment and comes with some pretty easy to use design software. Then you just print out the design to your piece of wood.

Painting the sign was the most tedious part of the project, nothing fancy there, just a lot of time and blue masking tape. As its an outdoor sign, I also added several layers of lacquer.

Here's a video of the Carvewright in action

Step 2: Uploading a Lighing Pattern to the Rainbowduino

As the Rainbowduino does not have a USB port, you'll need the additional UartSBee to program it. Since it's Arduino compatible, you use the same Arduino IDE software to program and upload sketches.

There are a few ways you can go to program the Rainbowduino:

1. Use a graphical editor called mtXcontrol written by Toby Tobes
2. Custom code from scratch
3. Find an existing lighting pattern someone else did and just upload it

I was lazy and went for number 3. I think the pattern though is very nice which is the one in the video. If I ever change my mind, I can always remove the Rainbowduinos, re-program them, and then re-mount them.

It turns out that getting mtXcontrol to work on Windows is not so easy and involves copying lots of files and ensuring they all go in the right place. So to make things easier, I wrote an install package which automates all this which you can download here (sorry, Windows PCs only, it's a large 450+ MB download). Also if you use the mtXcontrol, you must set your UartSBee manually in your Windows device manager to COM1. It will only work if it's on COM1. The Rainbowduino also needs external power when you are programming it so be sure and also have the +6V power supply plugged in.

Step 3: Weather Proofing the Electronics

The sign is outdoors so here's the things I did to weatherproof it:

Before final mounting, sprayed the Rainbowduinos with Electro Seal Ducky spray. This stuff is really good for electronics and outdoors. You just spray it on and it coats the electronics with a thin film.

Filled in the gaps around the square opening for the Rainbowduinos with Silicone.