Skinput is a technology that uses bio-acoustic sensing and pico projectors to turn the human body into an input surface. It allows users to control devices by simply tapping on their skin. Sensors detect vibrations and acoustic waves produced within the body when a finger taps the skin. These signals are sensed by an arm band containing wave sensors connected via Bluetooth. Skinput provides an always available mobile input without requiring the user to directly interact with or carry a device. However, it can be sensitive to environmental noise and accuracy depends on body type. Potential applications include use with mobile devices, gaming, assistive technology for paralyzed individuals, and more.