I’ve seen many LED cube projects pop up on relevant blogs (HackaDay and MAKE blog to name two) and wanted to make my own but it never reached the top of my todo list until I recently started playing with the WS2812 RGB LEDs (more commonly known to some as NeoPixels). These delightful LEDs come in wonderfully small packages (I’m using the 5050 surface mount ones but I believe they are also available as through-hole 5mm LEDs). I made a spinning dodecahedron out of milled PCBs which was adorned with such LEDs (read about that here) and when I took delivery of the bare WS2812B LEDs, which only have four contacts (power, ground, data in and data out) I realised I could free-form them in a series of columns to create a cube. I expect this has probably been done before but as I was due to give a workshop on Controlling LEDs with Arduino I thought this would make an ideal example.
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Unfortunately I didn’t take many build photos. I started with some laser cut guides onto which I stuck the LEDs using double-sided tape. This allowed me to solder the stripped solid-core wire to each of the pads. Positive and Ground were straight columns terminating at the top while data cascades from the data out of one LED into the data in of the next. Data runs up one column and down the next. A CNC milled circuit board distributes power to each of the columns and forwards on data from the base of the column to the next.
Laser cut acrylic was welded together with a solvent which wicks into the joints by capillary action. This made for a nice clean box with joints which don’t distract from the LEDs (straight edges rather than castellated joints). A battery holder (3 AA cells to give 4.5V), a power switch and an Arduino Mini with pin header for an FTDI programmer or a serial-over-Bluetooth module are hidden inside the base. Everything is held in place with a couple of blobs of hot melt glue.