Turn Your 3D Prints Into Glowing Displays with This Simple Spray Treatment
The ProtoSpray process opens up potential to develop interactive objects of different shapes.
Most experienced makers are familiar with electroluminescent (EL) wire, tape, and panels. They’re commonly used for lighting accents, particularly in the cosplay community. The light comes from a layer of phosphor, which glows brightly when exposed to alternating current. That simple construction means that a wide range of form factors are possible. That also means that you can make your own EL lights with the right materials. You can even add glowing EL panels to pretty much any 3D-printed object’s surface you want thanks to a team of researchers from the University of Bristol and MIT Media Lab's ProtoSpray fabrication technique.
If you were to cut a cross section of EL wire, you’d see a center core of copper wire, a coating of phosphor surrounding that, thin copper wire wound around the phosphor coating, and protective layers on top. When alternating current is passed between the copper wire core and the outer copper wire windings, it excites the phosphor and causes it to glow. To embed glowing EL segments to a 3D-printed object, you just need to replicate that construction. You can do that with readily-available materials and a dual-extruder 3D printer that can print two types of materials in a single print job.
To achieve that, you’ll need two types of filament: an insulating PLA (any regular PLA will work) and a conductive PLA (ProtoPasta and others sell this). Your 3D model should primarily be made of the insulating PLA, with the conductive PLA electrodes running through that to a surface layer where you want it to glow. You then spray a dielectric layer on top of that, followed by the phosphor layer, a conductive layer, and finally a protective coating on top. You can then connect a regular EL inverter to your electrodes to light them up. If you want something like a seven-segment display, you can simply use an Arduino to control relays between your inverter and the electrodes for each segment of the display!
More details on the ProtoSpray project can be found in its paper as well as team member Ollie Hanton's Instructables tutorial here.