A touch detection device for detecting touches on a given surface. The inventive device includes a surface where a touch generates acoustic waves, transducers that detect these waves, a controller that calculate the location of the touch and a host device where the touch position is used to communicate with the application program. The screen is formed from any material that is capable of propagating acoustic waves. Plurality transducers are placed on the screen. These transducers detect acoustic waves generated on the screen. The screen is calibrated by touching it once and a map of arrival time ratios are generated and saved in the storage unit. During the real time operation, a touch on the screen generates acoustic waves that are detected by transducers. The output of each transducer is sent to a controller unit where the time differences and their ratios are calculated and compared to time ratios.
