This instructable is going to show you how to put an LED onto a tire to light it up. I chose to build a circuit that had a switch so that it can be turned off. This is to conserve battery power because the effect is not as cool in the bright sunlight. Another feature that is to conserve battery power is to use a spring that completes the circuit only when the tire is spinning.
Step 1: Parts and Tools Needed
Step 2: Seting Up the Wiring
First we need to set up the wiring. Solder two wires to the switch so that you can turn the circuit on and off with it. Next take the 3V battery and use electrical tape to connect two wires to it. One of the wires having the switch on it. One wire on positive and one to negative. It does not matter if the switch is on positive or negitive.
Step 3: Make the Spring
To make the spring, it works best to use the thinnest wire you can find. (I did not use thin wire and my first version did not work as well.) Take the wire and wind it around something like a screw driver like 4 times.
What we are trying to do is use centrifugal force as the wheel is moving. This will force the end of the spring outward. The trick is to put the exposed wire that is connected to the LED in a spot that when the tire is spinning and the spring is being pushed outward it will come into contact with the wire and complete the circuit.
Step 4: Complete the Circuit
Now you need to finish soldering all the wires together. Be carfule when soldering the LED because it is polerised. The circuit in the picture below is very sloppy and could be cleaned up and smallerized. Notice that the end of the spring is hovering over a exposed wire. The enertia of the moving tire will push the end of the spring down until the two wires are touching. Then the LED lights.
Step 5: Put the Circuit on the Tire
Now you need to put the completed circuit on the wheel. For me I just used electrical tape because I do not have anything else like duct tape. The electrical tape seamed to work fine. The most important thing is to make sure to align the spring with the exposed wire. Align the rest of the circuit any way you like to make it fit. Once you get it on make sure that it does not hit anything when the wheel is moving.
So for my project it did not really work. Like I said before I did not use wire that was thin enough for the spring. If your test does not work and you notice that the spring is not completing the circuit when the tire is spinning you can try to weigh down the end of the spring with solder or something. This will help the Centrifugal force to act on better on the spring.