Design of an ultrasonic interface for a graphics tablet

A cost-effective design of an ultrasonic interface to a graphics tablet is accomplished by means of PIC microcontrollers. This paper analyses the design and implementation from requirements capture through high-level design to circuitry. Ultrasonic transducers enable direct placement of the tablet mechanism above an LCD so that the image is viewed as it is created. Results show that the prototype tablet has up to 0.8 mm resolution.