Step 4: Build the Card
Cut three pieces from cardstock: one large piece to be the card itself, one piece half that size to use as the frame for the acrylic, and one small strip which will act as the switch.
The large piece is simply folded over and set aside for now.
Cut the middle out of the frame so that the picture and message on the acrylic shows through, and leaves room for the electronics at the bottom. Hot glue the acrylic to the frame.
Hot glue the LEDs to the bottom of the frame and then use epoxy to make sure they're attached securely. Make sure the positive and negative leads of the LEDs are on the same side! After that's cured, bend the leads around so that they are very close to each other (see pictures). Wrap both the positive and negative leads in a bit of foil.
Put the coin cell battery between the leads--your card should light up! If everything is in working order, hot glue the coin cell in place.
Wrap about an inch of the tip of the small strip of cardstock in tin foil. Slide it between one set of LED leads and the battery. You should be able to slide it back and forth, turning the lights on with the foil part and off with the paper.
Position the strip so the paper part is between the batteries and the leads, but the foil is just a little way past. I stretched a strip of electrical tape and hot glued it in place to create a bit of tension over the lead/strip/battery sandwich.
Cut a little notch out of the side of the frame for the on/off strip, and hot glued the frame to the card. Bend the strip (see pictures), place a dab of hot glue on the end, and close the card. Once it cools, when you open the card, it should turn on!