Here are some detail photos on how I built the octahedron. I was originally inspired by a project called N-Light by the Numen art group, and wanted to create a variety that used programmable LEDs.
I created the basic design, and most importantly the pyramid joints that connect the acrylic panels, with Sketchup. My friend @Terry_Hudson 3D-printed the pyramid joints using his delta-style 3D printer.
I bought the half-mirrored acrylic from @TAP_Plastics and cut it to size by hand (slicing my thumb in the process, oops!).
When it came time to assemble the octahedron for the first time, I realized I’d forgotten some important details. It turns out, fitting together a 3D shape like this requires several joints to meet their panels simultaneously. I also hadn’t planned how I would mount the LED strips at the edges, a major oversight and stumbling block. I also joined the LED strips with 18 AWG wire, being overly cautious because I hadn’t worked with this much power before, but the wires were too thick and inflexible, causing excess stress at the joints. I re-wired it with 22 AWG wire and decided to simply glue the LED strips in place with Permatex 66B silicone adhesive.
Finally, the first LED was showing signs of some broken solder points, and I decided to lop it off and replace with an LED from a spare strip. At that time, I also re-wired the power connection and replaced my Arduino Due a much more compact DFRobot Beetle.
Now that it’s done, I can’t wait to get to programming it!
