A Question of Scale

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Since creating the Jumbo Servo I've been thinking about what else I could make in a jumbo size. The LED seemed the obvious choice.  I started by looking at pictures of LEDs up close. I then went on the hunt for different parts to help me along. Luckily I'd seen in the local IKEA some glass domes. I put one of those in the trolly and headed to the checkout, stopping to check the "junk" area before left. There I found a plastic dome with some LED lights, it had a better height to width ratio so I swapped my glass one for that. I also ordered some 10W LEDs and some gold and silver filament. I waited until those LEDs had arrived before committing to the project.

 

CAD

I modelled the LED using Fusion360, and put large holes down the middle of the legs for the wires. I exported the parts I would need to print as STL files.

 

Electronics

The electronics for this project are exceedingly simple. Just a 3W Red LED, resistor and a 12v power supply. I used copper wire from some "twin and earth" to replicate the tiny wires you see going from the semiconductor to the legs.

 

Printing

I did have some challenges printing this. Firstly I printed the legs in draft mode on my printer. Because of the thin wall size the printer omitted some of the walls! So I stopped the print then printed it again mirrored so that I could stick the two halves together. This worked quite well as it means I did not have to thread the cables through the legs. I used hot glue to hold the wires and halves in place.

 

For the base of the dome I used clear PLA, I realised that I did not have either the filament or the time to print it at the thickness I desired so cancelled the print after the first 3 layers so I had a nice solid disk to work with. I also spotted that there was no way to post the legs through as I'd modelled them with the wider section used to stop the LED going through the PCB. So I sawed my base in two and glued it to the dome. It's a bit flimsy so probably best to print or saw myself a thicker base at some point.

 

Resistor

No sophisticated constant current supplies for this project. Just an inline resistor. That was hidden inside a jumbo version of the resistor made from some pipe lagging and electrical tape.

 

Demo

The bit you've all been waiting for, the demo!

 

 

{gallery} LED Gallery

Jumbo LED and jumbo resistor

Circuit: Here's a shot of the LED and the resistor that was just out of shot in the video. A 10mm LED for scale.

Legs in parts

Legs: Printed in 2 parts then glued together

LED from top

Top: LED from the top

LED from side

Side: LED from the side

Lit

Lit LED: The limiting resistor is quite large, the device can go a lot brighter than this

Led Lit from side

LED Lit: Here it is lit up from the side.