Light emitting diode dot matrix display system with audio output

Abstract

A dot matrix display system made up of light emitting diodes (LEDs), in which one or more LEDs (50) are modulated and encoded with audio information or messages, is disclosed. The system has a LED dot matrix display panel with an interface circuit to a computer, an audio signal transmitter (200), and a receiver (300). An executive program runs on the computer for the visual display control of characters, decorative pattern or messages on the display panel. The receiver combined with a speaker (80) is located at a distance from the display panel. The receiver (300) is designed to demodulate the optically transmitted audio information and broadcast the messages with the speaker (80). The modulation of the LEDs (50) includes a voltage-controlled oscillator (VCO) for varying the frequency of on/off periods of said light emitting diodes. The frequency is high enough such that the perceivable light appears to be constantly illuminated to the human eye.