A screen system includes a display, three or more sensors, a processor connected to the display and the three or more sensors, and a clock connected to the processor. When a position on a display is selected by a stylus that includes one or more emitters, the one or more emitters each emit a pulse or a series of pulses. Each sensor generates a receive message when the sensors receive a pulse. Each receive message includes an identifier identifying which sensor transmitted the receive message. The processor then determines the location of the emitter or emitters in the stylus and the position on the display using the sensor identifiers and a respective time associated with each receive message.