- One CR2032 battery (I got them for about 16 cents on ebay when I bought 100)
- Two blank PVC ID cards (Again, I got these for about 16 cents - find a specialised ID card printing store on the web near you - I used www.digitalid.co.uk)
- One 3mm High-intensity white LED (Ebay again! I got 100 for about $16, so 16 cents each again!)
- Some double-sided foam adhesive tape (I got mine from an office supply store for a couple of dollars - you just need tape that is thicker than the battery you are using - mine was 4.5mm thick)
- Some self-adhesive copper tape (Ebay! Mine cost a few dollars for a long roll of 1 inch thick tape, and I cut it into thinner strips, but you could also buy the thinner version)
You will also need a soldering iron (plus solder), a cutting knife, some spray adhesive, and a way of printing the front of your card - you can use a colour laser or inkjet. I printed on paper and laminated it, but have had success before with printing in reverse on OHP transparency film which can look good as well.