Skinput technology turns the human body into a touch interface by using sensors to detect vibrations caused by taps on the skin. It consists of a small projector, Bluetooth connection, and bio-acoustic sensors in an armband. When the user taps their skin, the sensors detect the transverse and longitudinal waves produced. Differences in bone density and tissue allow the system to determine the exact location that was tapped by analyzing the wave variations. This could enable new ways of interacting with mobile devices and games without directly touching a screen. While promising, challenges remain in accuracy and cost before the technology is commercially available.