IBM engineer writes open source software allows tap control of laptops

An IBM engineer has come up with a system that allows Linux users to control computer functions by tapping the casing.

The software uses the accelerometer built into IBM laptops, which is designed to lock the hard drive to protect against data loss if the computer is dropped. Nathan Harrington, a programmer at IBM currently working with Linux and resource locating technologies, designed software that uses the same sensors to detect tapping on the laptop's casing.

"You can access the embedded accelerometers on Lenovo (formerly IBM) ThinkPads, then process the accelerometer data to read specific sequences of "knocking" events -- literally rapping on the laptop case with your knuckles -- and run commands based on those knocks," he writes on the company's web site.

"Double tap to lock the screen, and knock in your secret code to unlock. Tap the display lid once to move your mp3 player to the next track. The possibilities are endless."

Suggested uses of the application include activating a password protected screensaver, change tracks on an MP3 player or "have the ThinkLight blink out a secret Morse code location of the WWII-era gold storage facility in Kinakuta." This last suggestion is a reference to Neal Stephenson's 'Cryptomonicon', a bible to uber-geeks.