Parts are all on order from China (and the Teensy LC is on order from wherever PJRC is). Everything so far is about $25. I'm planning on using another USB lighter for the power. They provide a nice little package for a portable project. I don't know exactly how I will get all these components inside it, though.

I know the teensy is overkill for this project, but it is giving me an excuse to get one and play with it. The first time I saw these featured on HaD, I wanted to use one. Now I finally am.

I'll post pictures in a month when I get the parts.