Basic LED Lit Badge / Keychain

A member from CCCKC approached me over a month ago wanting to make some special promotional badges for Defcon. They wanted something like these (http://inventgeek.com/Projects/Laser-Fab-LED-Necklace/overview.aspx) but wanted to keep the form factor of their previous badges (luggage tag size, basically). This is the first prototype version of the resulting LED badges.

These badges are glued together, so they don’t have any protruding fasteners, but the battery can easily be replaced (the LED can as well but that’s a little harder). The battery door is meant to be kept in place with a key ring or badge clip, but seems to stay in place with friction on the prototypes. I’ve included both 3mm (if you’re using 1/8” acrylic) and 5mm (for 1/4" acrylic) LED templates. If you want a thinner badge, use the 3mm LED version, but be warned that warping can be an issue if you etch it too deep. I have black acrylic in hand so the back and middle sections of the badges are cut from that, but there’s nothing stopping you from making the entire thing out of clear acrylic.

Things you’ll need:
- 1 Set of Laser Cut Parts
- Acrylic Glue
- 1 CR2025 Button Cell
- 1 LED (3mm or 5mm, depending on the thickness of acrylic you use for the top layer)

The badge consists of 4 pieces, the back, the middle bridging section, the battery holder, and the top. All pieces are cut from 1/8” acrylic, unless you decide to use a 5mm LED, in which case only the top will cut from 1/4” acrylic. The top piece is clear acrylic and has whatever artwork you decide to put on your badge etched in it. If you want the etched side of the acrylic will be inside the badge and not the outside surface of the badge remember to FLIP YOUR ARTWORK.

1. Remove the masking material on all your acrylic pieces.

2. Glue the middle bridge to the back piece (see my previous wiimote stand project for some details on gluing acrylic: http://www.thingiverse.com/thing:788).

3. Carefully bend the leads of your LED as shown. Remember that polarity matters for LEDs and that the outer case of the button cell is actually the positive of the battery! The negative lead of the LED should be flat against the bottom piece and the positive (longer) lead should ride the inside of the rim for the battery. Trim the leads up a bit and place the LED before continuing.

4. Glue the top piece on. You’ll want to hold the badge together while the glue dries, either by setting something on top or by clamping it together lightly. Too much pressure can cause liquefied plastic to seep out from the cracks where the pieces meet, so don’t overdo it!

5. After the glue dries, slide the battery in and watch it light up!