Two LED projects for light and sound

Lead Image © Dietmar Hoepfl,

Light It Up

Around Halloween last year, one parts order brought together two completely different projects: a light-up dress and a thunderstorm for a model train layout.

Last fall, I heard from a long-time friend that he needed help with an LED project. He was taking his daughter to a concert, and she wanted to wear a light-up dress. The girl's grandmother had made the dress, but they needed help lighting it up. After we discussed the possibilities, I ordered three spools of cool-white LED strips to get started.

LED Fashion

When the LEDs arrived, my friend and I used the dress itself to measure the strips. Each LED strip shipped with a connector already installed, as well as an extra connector in case you cut the strip apart. With a total of six "loops" on the dress, the design worked out perfectly. The top of the dress has four LED strips and the skirt has two (Figure 1). After testing each strip, we sent the LEDs to be sewn into the dress.

Figure 1: The dress wiring layout showing the separate top and bottom sections, battery wiring, and LED layout.

The top and bottom of the dress are completely separate, each with its own battery packs. Each loop of LEDs has its own power feed to the batteries; nothing was daisy-chained. To wire everything together, I used push-in connectors (Figure 2). Each connector will accept up to four wires and although I probably could have doubled up, I added a second connector to accommodate the extra connections that the top of the dress required. A final connector between the battery boxes finishes the circuit. Each battery box has a switch, so I didn't have to include one in the circuit.

Figure 2: Push-in solderless connectors. When used with solid wire connections, they can be disconnected with a good pair of pliers.

In total, it took about five hours to measure, cut, and wire all of the LEDs. Figure 3 shows the end result, which looked great and caught the attention of the entire audience and even the artist herself! Everyone was thrilled with the result, and I got to keep the leftover LEDs.

Figure 3: The finished dress with its young star striking a pose!

Thunder and Lightning

Shortly after the dress project wrapped up, the regional train show came through town. These model train shows, in case you're not familiar with them, usually set up in a local convention center with roughly half the space for vendors and half for modular train layouts. Trains are always great to see on their own, but these shows also offer listings of home layout tours, where you can see literally years of work come together.

While I was touring one of these home layouts, the proprietor and model builder mentioned that he wanted a thunderstorm over the trestle bridge on his layout (Figure 4). My mind immediately jumped to the leftover strips of LEDs. We chatted for a little while then I headed home to build a prototype.

Figure 4: The trestle bridge soon to be the site of a massive thunderstorm.

The lightning generator consists of two panels of LEDs made up of the leftover strips. Sound comes from a set of computer speakers that I ordered specifically for their subwoofer. Tinny thunder and lightning with no "kick" simply won't do!

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