The use of electromechanical film (EMFi) sensors in building a robust touch-sensitive tablet-like interface

The use of electromechanical film (EMFi) sensors in building a new robust touch-sensitive tablet-like interface is presented. The built prototype system includes a 40 cm x 40 cm metallic plate with four EMFi sensors attached to its corners (26 cm x 26 cm active area), a four channel amplifier, and a computer with data acquisition card and analysis software. When the user interacts with the plate, the sensors measure the pressure distributed to each corner of the plate. The software calculates the position of the interaction relative to the center point of the plate and the force involved in the interaction. The device can detect both the static and the dynamic force involved in the interaction, and it has an average error of 0.18 cm in detecting the location pressed. Experimental results are discussed and directions for future developments are suggested.