Cornell undergraduates Brian Harding and Cat Jubinski built a portable face recognition system for their capstone ECE 4760 project:

Our design consists of an Atmel ATmega644 8-bit microcontroller, a C3088 camera module with an OmniVision OV6620 CMOS image sensor, Atmel’s AT45DB321D Serial Dataflash, a Varitronix MDLS16264 LCD module for output, a 9-volt battery, and a small wooden structure for chin support.

The system is hooked up to a computer to train the pattern-recognition algorithm, but from then on it can enroll new users, delete old users, and recognize up to 20 enrolled users as a standalone system. Their very detailed report claims “an 88% successful login rate with no false positives” and includes testing data, schematics, source code, a priced parts list, and some ideas for improvement in the next prototype. [Thanks, Max!]