TouchScreen in your forearm skin - a modern solution

Annoyed with the tiny touchscreens on today's mobile devices? Well, your forearm can now solve that problem by becoming a part of a skin
-based interface that effectively turns your body into a touchscreen, say scientists.

An international team has come up with a system, called Skinput, which has the ability to detect the ultralow-frequency sound produced by tapping the skin with a finger, and the microchip-sized "pico" projectors now found in some cellphones, reports New Scientist.

According to the scientists, the system beams a keyboard or menu onto the user's forearm and hand from a projector housed in an armband. An acoustic detector, also in the armband, then calculates which part of the display is to be activated.

Chris Harrison at Carnegie Mellon University in Pittsburgh, Pennsylvania, working with Dan Morris and Desney Tan at Microsoft's research lab in Redmond, Washington, exploits the way our skin, musculature and skeleton combine to make distinctive sounds when we tap on different parts of the arm, palm, fingers and thumb.

They have identified various locations on the forearm and hand that produce characteristic acoustic patterns when tapped.

The acoustic detector in the armband contains five piezoelectric cantilevers, each weighted to respond to certain bands of sound frequencies.

Different combinations of the sensors are activated to differing degrees depending on where the arm is tapped.

Twenty volunteers tested the system and most found it easy to navigate through icons on the forearm and tap fingers to actuate commands.

The system could use wireless technology like Bluetooth to transmit commands to many types of device - including phones, iPods and even PCs.

The researchers will present their work in April at the Computer-Human Interaction meeting in Atlanta, Georgia.