An open source convention badge. The idea behind this is to have a very low cost, low power electronic badge. These could be built just for fun, or if you're throwing a conference, feel free to use the PCB as the badge, maybe build some, maybe let the folks at the conference build them.

Electronic badges have gotten pretty hip, but they seem to suffer from two primary problems: They are very expensive, and they need a lot of batteries.

The goal of the Open Badge Project was to build a badge that costs $5 or less and can run for a day or more on one 2032 battery.

The badge as it stands right now will only cost $5 if you build A LOT (1000 or more). The cost is closer to $6 or $7 for smaller batches at the moment, but that's still pretty reasonable.

The badge itself runs on a microprocessor called an ATTINY85. It has 8K of program space, 512 bytes (yes, bytes) of memory. That microprocessor then drives 3 shift registers. One for the button input, and two for the display output. Shift registers shouldn't be used to drive LEDs, but it works, and doing it this way keeps the cost down.