Creating a paper circuit in a card is a very fun project that teaches kids some basics about electronics and makes a fun gift. I have designed a Valentine card with a simple circuit design that you can download and craft.
To create the card, you’ll need an LED light, conductive copper tape (the guideline is sized for quarter inch tape but other sizes should work), and a 3V coin cell battery. I’m using a CR1620 battery in this example but other 3V sizes work just as well. I also recommend that you print the card on a heavier stock paper so that it can hold the weight of the battery and light.
Here are the links to download the card in PDF format.
Valentine Card PDF (US Letter)
Valentine Card PDF (A4)
I’ve learned the hard way that before applying any tape, you should always make sure the LED works. You can easily test this by placing the legs of the LED directly on the battery. Make sure that you put the longer leg on the positive side of the battery.
The card is marked on the front and back with some guides to help you prepare it. On the front side there is a dark square indicating where the light bulb will pop out. I cut out this out with an X-Acto Knife but you could also use a hole punch if you have one long enough.
The inside of the card has guidelines showing where the copper tape, LED, and battery should be applied.
Apply the copper tape to the card following the guidelines. Try to keep the tape as continuous as you can by folding over the corners instead of breaking the tape. This creates a stronger circuit by having a continuous line for the electrons to follow. (You can also overlap the corners if the tape is broken but that risks a weaker or broken connection.)
To put on the battery, create a tape roll so that it is sticky all around. Place the roll on the battery spot and firmly press down to create a good connection with the tape underneath. Then stick the battery on top of the roll with the negative side down. (The negative side of a coin cell battery is usually textured.)
Finally, bend the legs of the LED out so that they point in opposite directions. Make sure you keep track of which one is the long leg. Place the LED on the spot indicated with the legs overlapping the tape on either side. Make sure that the longer leg is on the positive side or the circuit will not work. Secure the legs with two more small pieces of tape. This will complete the circuit across the broken spot in the tape.
When the card is folded on the score line, the copper tape will touch both sides of the battery and allow the electrons to flow through the circuit – lighting the LED in the middle.
The card was created in Inkscape. It uses the font Destructo Beam by Blambot Comic Fonts.
The card is available under an International Creative Commons 4.0 by-nc-sa license so you are free to modify the card if you’d like. (Let me know if you do, I’d love to see what others do with it).
Valentine Card SVG format (both US letter and A4 included).