What you will need:
- 1 LED of your choice
- 1 CR3032 coin cell battery
- 1 Clear Bottle Cap
- Scrap Plastic Sheet
- Black electrical tape
Step One: Attach the LED to the battery (aka make a throwie)
Hold the negative lead of the LED (the shorter one) to the negative terminal on the battery. Secure with black electrical tape. Then connect the positive lead of the LED (the longer one) to the positive terminal of the battery. Secure with black electrical tape. Once the leads are secure, bend the LED back so that it lays flat against the battery.
Step Two: Create the backing for the device
Find a piece of thin plastic. I re-used plastic packaging from something I bought earlier that day. Place the bottle cap onto the sheet of plastic and trace the outside edge. Cut-out a circle that is roughly ~ 1/4″ diameter larger than the diameter of the bottle cap.
Step Three: Create a waterproof seal
Fill the bottle cap with the glue of your choice (both epoxy and hot glue worked well for me). Then quickly and carefully, place the LED face down into the glue. Do your best to make sure the LED is centered and pushed all the way in. The LED should be in contact with the bottle cap. Then glue the backing to the cap. Once the glue is dried trim away the extra plastic and glue around the bottle cap.
Step Four: Test the seal
Yay it’s waterproof!
Step Five: Attach your new creation to your helmet
Attach the LED to a helmet of your choice with double sided tape.
Step Six: Wear it!