Humble Electronics #002 - Decorative LED Light Boxes (Summer 2023, long post, project prototype)

This was an idea inspired by Big Clive's "Supercomputer" that he has in the background of his YouTube videos. He talks about it here in June of 2020. Then learnelectronics did one with quick flashing colored LEDs in September of 2020.

I found slow flashing RGB LEDs on Amazon and got my hands on a 100 pack. Its a 2 terminal device because its got a microcontroller the size of a pepper flake embedded in it that changes the colors. Basically, this circuit is many pairs of resistors and LEDs in parallel so they all have 5V across them. The slow flashing is more my speed and casts a nice glow I can run all the time. I had a lot of 360 ohm resistors because Amazon was out of 330 ohm. Maybe I didn't search hard enough. I really need to start buying from Mouser.

I finally got around to working on it this summer (2023). I ran the concept on a breadboard for a while to see if I liked the effect.

It didn't look too bad there so I moved onto some prototype board.

I put 5 LED and 360 ohm resistor pairs on a prototype board and found it was not the easiest to wire because I put the resistors on the back side so they wouldn't block the LEDs. This board also had three holes in a row linked together but it didn't suit this arrangement particularly well. It was also very small.

The first one was a mess but I tried it in a box anyway.

This is a stand for a paperweight I received from my sister. It is translucent purple resin with an iridescent underside coating that lets the colored light through.

It looked great but I had other ideas in mind and needed to make my board neater. This board ended up somewhere in my LED drawer to be used later, maybe.

Since we have a laser cutter, I envisioned a grid of lights, like the "Supercomputer", so now I had to make one. I grabbed the biggest prototype board I had, and laid out where I wanted my LEDs evenly spaced. This type of board was easier to lay out the resistors on the back and the LEDs on the front and solder them in parallel.

I also threw in a capacitor across the power rails for smoothing but it really didn't need it. Here it is powered up with some parchment paper over it for a diffuser.

Then I needed to design a box to frame it. I design laser projects in Inkscape. It produces the vector graphics files (*.svg) my laser cutter can use. While I was designing the front, I thought the square openings looked boring, so I changed them to elongated Hexagons. I designed a grid that would fit behind the face to separate each LED into its own cell.

This is how my box looks put together with the lights inside and parchment paper and a clear Dollar Tree plastic cutting mat for the diffuser. This is just a temporary power connection for testing.

It throws out a lot of soft lovely light. After I took these shots, I added a micro USB power jack and switch on a wood ledge across the back and Kapton taped the heck out of the back for insulation. This is a pretty and functional prototype with a finished size of 8 cm by 10 cm plus the clip feet. It looks like glowing jewels and doesn't distract too much with its soft waves of color. I tried a 9V power supply on it before I added the USB jack. It was brighter and ran well with that large, for an LED, voltage but gave off more heat.

The next question I had was could I use my laser cutter to make a base for my LEDs? I cut a base for 6 LEDs to concentrate the LEDs in the heart shape paper weight . I cut some holes for 5mm LEDs into a square that would fit in the previous box. The LEDs fit snugly then I soldered them up in the same way with the 360 ohm resistors in series and each pair in parallel.

Again I Kapton taped the heck out of it. I suppose I could have hot glued it for insulation instead. I added a micro USB jack but no switch this time. This has some Japanese rice paper as a diffuser. Then it was ready for the paperweight.

These have been sitting in my workspace on constantly and I don't have any problems with them. Making them with a wooden base for the LEDs definitely is extremely cost effective and I can arrange them in countless ways. I've thought of many ways of creating these from the simple versions here to absurd ones.

I have made some single boxes to test how big of a cell an LED can illuminate and it all really depends on the look you want. They look nice at different depths and widths of openings depending if you want the colors completely diffused and mixed or showing whichever individual colors are lit without much mixing. If the inside is painted white, the light looks nicer with it bouncing around the inside of the box. I will get some smaller resistors, like 100 ohm, to use on a 5V supply next time.

More information on the boxes will be in a Laser cutter post

Happy Making!

Michelle