Jumbo LED

February 4, 2019

I decided to create a Jumbo LED for the Element14 “A Question of Scale” Project14 challenge. I ordered some 10W Red LEDs from AliExpress, some silver and gold filament from Rigid Ink and found a dome in the junk section at IKEA.

The legs were designed in Fusion360, thanks to Enrico Miglino for reminding me that the anode (positive) leg is a bit longer than the cathode (negative) one. I decided to print in silver as I had more of that.

Printing Challenges

The legs were right on the limits of the printer bed and due to a slight misalignment of the bed they overhung by about 0.5mm. That meant that there was a slight misprint on the end. I also printed the legs in draft and due to the thin walls the slicer completely skipped some of the walls. So the print was stopped and I printed the other side separately so they could be glued together. I’ve fixed that issue in the model now and also adjusted the cathode to be slightly shorter.

The base also caused a problem. I’d added the stepped part to the legs which controls where they sit on the PCB. This hence would not go through the holes in the base so I ended up stopping that print too and slicing the base in half with a saw. I’ll likely cut a new base from some thick acrylic I have.

The models can be found on the Workshopshed Github. At the time of writing the base has not been fixed up and needs splitting in 2.

Electronics

Nothing much here, just a series resistor and a 12v power supply. I’ve not actually checked the forward voltage of the LED so the resistor was selected based on a value that was not blinding when testing. The LED module was soldered to some stiff copper wires to look like the bonding wires used for the semiconductor. I used the thickest flexible wire I had to hand but even that looks dwarfed by the other components. I’ll see if I can get some scale wire to improve the look.

Have you made anything in giant scale? Let us know in the comments below.

By Andy from Workshopshed 2 Comments

  Posted in: Jumbo LED Tags: 3d Printing, CAD