Make a simple circuit on an everyday object using copper tape, a battery, and an LED. Involves simple soldering.
Components (available from Digi-Key):
- CR2032 coin-cell battery (3V)
- CR2032 coin-cell battery holder
- White, Four-Legged LED
- Copper Tape (1/4″)
Plus a holder for a tea-light candle or another object you’d like to make the circuit on.
- Soldering iron + solder
- Hot glue gun
Gluing down the battery holder
Use hot-glue to attach the battery holder to the bottom of the candle holder.
Attach copper tape
Stick a piece of copper tape to the tab on one side of the battery holder, then wrap it around to the middle of the candle holder. Repeat on the other side, leaving a centimeter or so between the ends of the pieces of copper tape.
Gluing down the LED
Fold open the legs of the LED. Note that one of the metal pieces that goes through the LED (and extends out to form the legs) has two little holes in it. That’s the positive side of the LED. Make sure you connect it to the piece of copper tape that goes to the positive side of the battery holder (which is marked with a small imprint on the battery holder). Place the LED so that one leg is on one of the pieces of copper tape, and the diagonally-opposite leg is on the other piece of copper tape, but the other two legs don’t touch the copper tape.
Soldering the components
Next, solder the tabs of the battery holder to the copper tape. Then, solder, the legs of the LED to the copper tape.
Testing the circuit
Next insert the battery. The LED should light up.
Some things to try if the LED doesn’t light up:
- Try with another battery (in case the first one was dead).
- Make sure that only two of the legs of the LED are touching the copper tape (or the solder). One of the legs should be positive (i.e. part of the metal piece with the two small holes inside the LED) and one should be negative (i.e. part of the other metal piece).
- Check that the positive leg of the LED is connected to the positive tab of the battery holder.
- Make sure that the solder isn’t broken between the tab or leg of the component and the copper tape.
- Make sure that the two pieces of copper tape aren’t touching each other.