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.
What is a Teensy?
If you aren’t familiar with the Teensy, they are Arduino-compatible boards from PJRC. The Teensy 3.1, which is what this SDR project uses, is an ARM M4 with 256k of FLASH, 64k of RAM, and a 96MHz clock. Oh and it only costs $20.
You can find out more about the Teeny 3.1 here.