This is an idea I had for wall lighting. I wanted modular lights of some kind, and I liked the look of tessellating triangles. I am pleased with the result, as a proof of concept. Eventually I want to scale it up and integrate IOT functionality.

Hopefully the video provides the most concise explanation.

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This is a very straightforward project, and can be scaled or adapted in many ways. The panels are vacuum formed from 2mm HDPE plastic, using a three-sided MDF mould.

I made a very quick vacuum former a while back, and would say that it's probably one of the best shop projects I've done, given how well it works for the time invested making it. It consists only of a sealed box with a series of holes drilled through the top. The only other tool you'll need is a heat gun.

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If you want to 3d print the shapes instead, attached is an example .stl file with the sizing I used.

pyramid.stl
Download View in 3D

Step 1: Making the Former

If you're interested, the base I used was an equilateral triangle of radius 80mm, and the depth of the pyramid is 20mm. You could sculpt a solid block too, but I preferred cutting three equal shapes in MDF and hot-gluing them at the seams. Bare in mind that hot glue could melt during the forming process because of the heat on top. This wasn't a problem for me though.

I then covered the top surface in tape. Note that even small surface features, like edges of the tape, show through when you form the plastic over it. If you want a smooth part, you have to make a smooth former.

A really cool alternative to buying HDPE would be to reuse milk bottles, which can be vacuum formed too (the only limit being the size of the offcuts).

Step 2: Forming Pyramids

When you put hot plastic on a vacuum bed and apply a vacuum, it quickly takes the shape of the surface beneath. This means it stretches slightly. For this reason, you don't actually need a sheet much bigger than the part itself (unless the part is really tall). In my case, I left about 40mm / 1.5 inch perimeter around the part. You want to avoid pointed edges in parts - the plastic tends to tear under pressure, causing air to leak.

You'll quickly get a feel for the process. Begin by heating the plastic panel, (time varies on thickness, material etc.) until it is floppy but not curling in on itself too much. Move the heat gun in rapid strokes - this is especially important later on: it prevents punctures from overheating a localized area. Drape the hot plastic over the part, and apply the vacuum. I usually press it down on the edges at this point, and then reheat the plastic to help it stretch the final distance around the border of the part. Be patient with heating to avoid tears.

Step 3: Backboard

I am lucky to have access to a CNC, so I decided to cut out a back board. This does however prevent you rearranging the tiles. It was a quick solution but I'd like to experiment with this part of the project more - the panels didn't fit perfectly either because of the corners of my bad former.

If the panels were self-contained, i.e. there was no wiring, it would be interesting to use velcro, magnets, or another temporary method of affixing to make wall lighting that can be arranged easily.

Step 4: Electronics

As a proof of concept, I wired in some white LEDs, and later some flashing ones. The next step is to add addressable LEDs, like I have done in past projects, to create dimming/colour-changing effects. I would like to use this as a bedside light, so being able to choose a warm, dim light is great. I would recommend using neopixels if you want to add this kind of functionality.