Josh Corn: Giant Battery for a Giant LED

For this innovative switch, I decided to take my plush LED project and change it into a table lamp. The concept was to create an equally proportioned coin cell battery to place between the legs of the LED to make it turn on. I began by ripping apart my plush project and prototyping the wiring for the circuit.
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After I got the circuit working, I decided to work on creating the battery. I ordered a 6″ diameter block of aluminum from McMaster Carr and decided I would CNC etch the lettering into the surface. In working with the staff at the VFL, we realized that the CNC costs would be prohibitive. I still wanted to move forward with the etching however so we decided to try a technique that they hadn’t attempted before: electroetching with salt water.

I began the process by cutting out the shapes I wanted to etch on the vinyl cutter.
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After painstakingly cutting out the vinyl negatives for both sides of the LED, I sanded the block of aluminum to prepare it for etching.
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I used transfer paper to apply the vinyl onto the battery surfaces.
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I added a wire to the block to connect to the hot lead of the battery.
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And then I wrapped the rest of the block in electrical tape.
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A plastic tupperware was borrowed and filled with salt water. I grabbed a tiny scrap of galvanized steel and attached a wire that ran to the negative lead on the battery.
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When we finally connected everything, the exposed galvanized steel immediately began bubbling.
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After a couple minutes, the water became pretty black and gross as the galvanized coating was removed.
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I checked on the etching multiple times and eventually moved to a larger trashcan so I could stand the block up during the process. We also tried using a scrap of aluminum as we feared that the fumes from the galvanized steel were toxic. As the bubbles became less frequent, I changed out the battery to a fresh one. This definitely made the process move along faster. After about 5 hours, I was happy with the state of the etch.
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After the battery was complete, I applied some conductive aluminum tape around the edge to complete a circuit also made from the same tape.

I realized that it was fairly silly to use “conductive aluminum tape” as the aluminum itself should be conductive enough to make the circuit work. Trying the circuit again with only aluminum rods as the LED leads and the battery to connect them, I got the project to work as I intended.

I then worked on refining the look of the LED and wiring it up for my presentation. I’m pretty happy with the final result.

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I hope to continue working on this project and finish it up as a standing desk lamp.