My Improv LED Necklace
For my physical computing class we were given 2 weeks to make a device that took an input action, gave it a context and then produced an output. We had a list of possible inputs, contexts and outputs and I chose to have dancing as my input, a necklace as my context and colour as my output. I made an necklace of flashing LEDs that turned on and off as the person wearing it danced back and forth. So using the two circuits previously posted (the reindeer antlers and the christmas bulb necklace) I took components and knowledge I learned by ripping the apart and applied it to this project.
I started by sketching out my circuit in a very informal way.
I knew from the beginning that the power supply was going to be the most challenging component of the device so I drew up several possible ways of creating the power supply. I decided that the unnumbered one of the left would be the best layout for the power supply.
The easy part was soldering the LEDs together. I went to active surplus and picked up some LEDs that flashed red and green and a tilt switch with a metal ball baring inside. Then I began soldering together my LEDs in a series circuit using the black wire from the christmas necklace that I took apart. After I soldered each one together I would wrap the connection in a small piece of black electrical tape. This was mainly just for aesthetic reasons.

Once all of my LEDs were strung together I began assembling the switching device and power supply. I used a tilt switch as pictured below and a small on/off switch also from the christmas light necklace.
The metal ball tilts to the left or to the right to disrupt the connection and break the circuit. I connected the string of LEDs to one side (bottom) and the on off switch to the other (top). This left four contacts unused, three of them I broke off while I left one to attach the other end of the LED string to with some black thread. Then I hot glued the on/off switch to the side of the plastic casing of the tilt switch. I also covered the tilt switch in black electrical tape for aesthetic reasons.

The cause of most of my challenges on this project was the power source, the first problem being actually making it. I first used a small rubber tube that was used as battery casing in the christmas necklace but I needed a way to attach the wires so I fabricated a small case out of this foam from an old bathtub toy.

I cut it to the size of the three watch batteries and then wrapped it in electrical tape for support. I then poked holes in the side and hot glued the wires in so that they wouldn’t move. Now my first mistake, I hooked up the power supply to the LED string without using the tilt switch. So I tested it out and it worked fine and the LEDs lit up and flashed. I continued on finishing up everything and as the last step I wired in the tilt switch only to find out that my LEDs barely lit up. I needed a bigger power.



So I ran out and bought some more watch batteries and attached them to my three exsisting ones so that I had six batteries in total. Now my second problem was that since I had more batteries now my battery casing didn’t fit. I had to cut a larger one out of the foam and reconnect the wires. The last challenge I had to overcome was to make my wires going into my power supply make a proper connection to the battery pack.



The wires seemed to always get pushed into the foam and not touch the battery contacts meaning I’d have to squeeze the battery casing in order for power to flow. I tried using tinfoil but the wire even had problems consistently making contact with the tinfoil squares. I found the solution to the problem to be putting small pieces of foam between the wire and the wall of the casing so that they protruded forward.
Once I overcame this I had power and after a few aesthetic modifications I was finished and could rock out in red and green style.
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