I made this piece of wall art for the company I used to work for, Coupa Software. It is a pixelated abstract representation of the company's blue flower logo icon measuring 4x4 ft and features addressable LED lights behind each "pixel".
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Step 1: Design
The first step was figuring out the design of the pixels. In Photoshop, I imported a picture of the logo and began placing identically-sized squares on top of it in a new layer so that they matched the color underneath. I used a darker blue and a medium teal as well as some random white squares, and had some loose pieces floating off the sides which I decided would represent bits of pollen and help make the whole composition a little less rigid.
Using a grid, I figured out where the 1x2" framing boards would go and what sizes I'd need to cut to create a backing for my two 2x4' flat boards. (The only reason the whole thing is cut in half and not one solid 4x4' piece is due to limitations with transporting it in my vehicle!) I also marked where I'd have to drill some wide, shallow holes for screws to go in so that they wouldn't poke out past my 1x2s in the back, assuming that each pixel would be held on with 2 screws, one in the upper left and one in the bottom right of the square. In the center, where there the 1x2s aren't beneath the big flat boards, I didn't need these holes because there's already a gap between the board and the wall.
Step 2: Constructing the Backing Panel
Building the backing panel was pretty straightforward. After marking and cutting the 1x2s to size, I hammered some panel board nails through the front flat sheets to attach them. The fact that my panel was in two pieces actually helped since the boards were not the best quality and kind of warped, so the framing on the back helped to pull them into a flatter surface.
I wanted my backing panel to match the wall in the office where the piece would hang, so I applied some drywall texture to the whole thing before painting over it in an off-white semi-gloss.
Step 3: Testing Pixel Materials With LEDs
I had a long strip of addressable square module WS2801 LEDs, so I got a few different colors of acrylic squares in different opacities to test how they would look with the LEDs behind them. Some colors of light looked better than others, so I noted that when it came time to program the LEDs, I would stick to hues of blue and white mostly. I ordered the best-looking colors of acrylic from Tap Plastics, precut to 4x4" squares, which ended up costing a dollar a piece. I also bought several feet of two different kinds of diffusion material, to put behind the clear squares.
Step 4: Assembling the LEDs
I measured and lightly drew a grid on my backing panels, and following my design, marked where the LEDs needed to go. The LEDs conveniently have a hole for a screw in the middle, so I simply screwed them into the board with some 3/4" wood screws, snaking the rows back and forth. The wires had to be cut in a bunch of places, but for the pixels that would be right next to each other, the connecting wires were a perfect length. For the LEDs whose wires I had to cut, I drilled holes to pass connecting wires through, and soldered them together in the back. Using a template square, I also marked and drilled holes for the screws that would hold each acrylic pixel.
Step 5: Attach the Pixels to the Panel
Prior to affixing the pixels, I had to get the two halves of my panel together. I had taken it into the office by this point, so I drilled a couple of flat metal bars into the back at the top and bottom to keep the halves together.
Each acrylic pixel was drilled in the corners with a drill press - again, using a template piece to mark where, ensuring they would be drilled identically. I bought a few lengths of size 6-32 machine screws, ranging from 2.5 to 4 inches long, because I wanted the depths of each pixel to be staggered, just to make it a little more 3D and interesting. I held the acrylic at the top of the screw head with a nut, then added a nut near the bottoms of each screw, pushed them through the board, and added a nut on the back, essentially sandwiching the panel between two nuts. I would NOT do it this way if I were to redo it - the nuts don't stay tight on the plastic and I ended up adding lots of glue to keep things from wobbling around. Instead, I would probably cut many pieces of clear acrylic tubing and use that as spacers between the panel and the acrylic, with a single nut on the back of the panel. You can see in this step where the wide shallow holes were necessary in the framing so that the screws don't poke out the back.
Step 6: Adding the Arduino
My design included a little pocket for the Arduino, which is just screwed to a flat piece of plastic, and allows for somewhat easy removal of the Arduino without having to take the whole thing off the wall. A screw terminal block helped to distribute power from the power supply.
Programming it made use of the WS2801 library from Adafruit. Currently it's just running a simple circular fade pattern, but it could be made to do something more interactive with the addition of a sensor.
Step 7: Hanging It on a Wall - All Done!
I added some miscellaneous bits of hardware and nylon rope to the back and hung it like a picture. Here it is doing its thing.