Edge Lit 3D Printed Pendant by dj_segfault

Last crawled date: 3 years ago

Overview
I got the idea for this project from Geek Mom Project's Layered Edge-Lit Pendants project. Her project uses a laser cutter to cut out clear and black plastic layers, and screws them together. But not everyone has access to a laser cutter, so I wanted to see if I could do something similar just using a 3D printer. The front and back are opaque, and instead of clear acrylic in the center to diffuse the light, I used clear PLA filament. The front contains the design in the negative space, letting the light from the center shine through.
Like her project, mine is electrically and mechanically simple, as the design has the battery insert into the top sticking out, so it's easy to turn on and off by inserting or removing the battery.
3D Printed Components
3D printed in three different parts that get glued together:
The back piece: Printed in the opaque color of your choice, any infill will do. This holds the back of the battery in, has loops to hang the pendant on, and also has 2 registration pins sticking up that go through the other pieces to guarantee alignment.
The center piece: Printed in clear PLA filament, diffuses the LED light. There is space for the LED body and leads, and the battery. There are holes straight through for the registration pins for alignment. You may want to play with the infill to get the right diffusion pattern for your design. 15% infill worked for me.
The front piece: Printed in the opaque color of your choice, This has the actual image in negative space for the light to shine through. The back of the front piece has 1mm filleted shallow holes for the ends of the registration pins. I provide two different front designs and either will work. You can make your own on the same design for your pendant. You can even make it 3D instead of just a flat disk. Just make sure it's 35mm in diameter, and holes for the registration pins, 12mm across from center and 8mm up from center, 3mm diameter and 1mm fillet.
Here is a link to my models in OnShape so you can see how they were built
Other Components
The LED. I used 3mm LEDs that take 2.2v or 3.2V and draw 20ma (different colors will have different power requirements).
CR2032 3v battery. In my test, this provides about 70 hours of runtime before significant dimming, and are readily available anywhere.
This may not be necessary, but to make better contact and make the pendant more robust, I cut some thin conductive metal that fits on either side of the battery, and used conductive glue to fasten them to the LED wires, so inserting the battery does not mangle the leads. This may not be required depending on how delicate you are with it.
Assembly
Print the front and back in opaque PLA
Print the center in clear PLA
Apply glue to the back and put the clear center on top of the back, making sure the registration holes go through the holes in the center
Put the LED in the slot in the center piece, making sure the wires are on the back and the front, not the sides. I didn't find it necessary to glue the LED in place, but you might.
Glue the metal pieces on the inside of the LED legs using the conductive glue, if you are using them, so the battery will press against the metal pieces and not the wires
Glue the front piece on top of the center piece, making sure to stay clear of your design.
Here's a video of my prototype in action