For my paper circuits project, I decided to make a Halloween-themed card that would have glowing LED eyes when the card was opened. I had to think of a way to complete the circuit when the card opened. I decided to use two pieces of card stock taped to the inside folds. One would be stretched downward as the card opened until it touched the center piece pointing out.
I found using the copper tape to be extremely frustrating. It was very easy to tangle and tear, so this meant having to cut it into smaller segments, but those segments produced their own problems by requiring the connecting strips to be folded over to connect the conducting surfaces. Even when I did this, the segments would still struggle to carry the current. Since I was using two LEDs, I had them each running their own tape to the battery.
After the circuitry was laid down, I covered over the copper tape with another sheet of card stock so that I could draw over it. I did the same for the other side of the card and created a cut-out skull face to go over the LED eyes.
The main problem I had was getting enough pressure to be applied to the battery and the copper tape. It required direct application of the hand to work, and if I had known that this was going to be such a big problem, I would have put the battery at the bottom of the card where the hand will more naturally hold it.
After placing the covers over each side of the card, one of the LEDs stopped lighting up. Eventually the both stopped working, but by that point I had already covered up the circuitry making it very difficult to troubleshoot. I would prefer to use copper wiring in the future rather than copper tape. The card stock is already quite rigid, so there’s no real benefit to the flexibility of the copper tape.