These colorful, illuminated party decorations make use of slow flashing RGB LED’s that change color all by themselves – no programming required. With the addition of a coin cell battery, magnets and a simple paper circuit, they come together quickly and make for a pretty tabletop decoration. The coin cell battery holder circuit – inspired by this article is especially nice because it makes connecting and disconnecting the circuit a snap, and holds the paper circuit in place to the lid – no soldering required.
- Clear jars with metal lids
- Vellum paper
- copper tape (1/4″ wide)
- CR2032 coin cell batteries
- Slow flashing RGB LEDs (like these)
- Paper or thick card stock
- Small neodymium magnets (like these)
- Scotch tape
- Decorative tape/stickers (optional)
Print a copy of the battery holder file ( MagneticPaperBatteryHolder.pdf) onto paper or thin card stock and cut it out. Fold along the dotted line. Stick the magnets to the backside of the paper, aligned with the black dots on the other side so that when the paper is folded they stick together. My magnets had an adhesive, but I covered them with scotch tape for extra stickiness..
Cut the copper tape, peel off the backing and adhere it to the traces on the inside of the battery holder as shown. Then bend the legs of the LED outward at a 90 degree angle and use a small pieces of copper tape to secure them on top of the traces. I added small pieces of scotch tape on top for security.
Now place the battery in the circle with the positive terminal down and close the flap to complete the circuit. The attraction between the magnets and the battery will help keep the circuit closed and in place.
The magnets will help the LED circuit stick to the top of the jar, but you can add a small piece of scotch tape to stop it sliding around. The light looks best when centered within the jar. Now cut a piece of vellum in the right size to line the interior of the jar. You can tape it in place if you wish, but the natural stiffness helps it adhere to the curve of the jar. If you want to add nice details, decorative tape and stickers on the vellum and/or jar exterior look quite nice (see below). These decorations look best in a slightly dim room, and even better in the dark.