A team of students from Cornell University are looking into alternative ways of creating a security system that can be locked or unlocked by using physical gestures in an enclosed space.
It is the final year project for [Ankur], [Darshan] and [Saisrinivasan] in their MEng of Electrical and Computer Engineering. The system prototype is capable of recording a gesture and then comparing the gesture with future gestures to lock or unlock the system. Consider it like a secret handshake to get into the office!
To analyze the gesture they are using four SparkFun proximity sensors setup in a linear array to sense the distance a hand is moved. An ATMega1284P is used to convert the analog sensor signal to digital for further processing. The project is extremely well documented, as it appears to be the final report for the project.
A short video after the break shows off the prototype and gives a good explanation of how the system works.