In this instructable, you will make a circuit on paper that triggers an LED whenever you fold it in a special way. It uses copper tape taped on an index card for the circuit. Whenever you fold the copper tape onto itself, the circuit completes and the LED lights up.

Step 1: Getting Your Ingredients

This is what you'll need to make this project:

A small index card to put the circuit on,
A roll of copper tape,
A round battery,
An LED of any color, and
A roll of tape.

Step 2: Putting on the Copper Tape

Cut a piece of tape significantly larger than the perimeter of the index card; you'll cut off the extra when you're done. Around a centimeter above the bottom of the index card, place down some tape spanning the bottom of the index card; now cut it off. I'll call this tape "A" from now on. Now place another piece of tape spanning the left side of the index card, but stopping around a centimeter above the tape you placed before. This is tape "B." This time, start a centimeter from the left at the top and go all the way to the right, but don't cut it off. Instead, fold it inward towards the left side of the card, and press down on the place where it turns. Then, go all the way down, but stop before you hit the other piece of tape. Call this tape "C."

Step 3: Taping Down the LED and Testing the Circuit

Twist the legs of the LED so that they turn at a ninety-degree angle. Next, put the LED in the upper-left corner of the index card, and tape down each of its legs to tapes B and C. Now, put the battery onto the bottom of tape C. Then, fold the card halfway between tape A and the other two. If the LED doesn't light up, flip the battery over.

If all is well, you have now successfully made our own paper-circuit LED switch!