Input method to enter linear data using fingertip pressure

This paper proposes a new user interface that provides a multi-valued, linear output according to fingertip pressure. Our proposed interface uses a strain sensor to detect microscopic strain caused by fingertip pressure on the chassis of a portable information terminal unit. An experimental prototype, consisting of a detection circuit with two strain gauges and an embedded MPU, was manufactured to verify operation of the user interface. The results indicate that the prototype system provides accurate linear.. output proportional to the fingertip pressure. With the proposed interface, the terminal units do not require a specific area, thickness, or position for input buttons in the chassis.