Several months ago I used my first software defined radio (SDR). This was a USB Dongle that did the digitizing and used Gqrx and GNU Radio for the actual decoding. Playing with an SDR is really fun. At the time I thought about using my Pi as the decoder, but found some performance issues. Imagine my surprise when I saw this project.
On rheslip’s Open Emitter blog, he has a project which turns a Teensy into a SDR. His latest update includes an enclosure for the project, making it a nice all-in one package.
At only 87mA it is slightly more power efficient than my PC-based or Pi-based setup.