Wireless audio communication over Infra-Red medium

In the modern era, a number of devices are going to dominate every sources of human in their day to day daily lives. These devices may be connected and/or controlled through Web, infra-Red (IR) and other means. Hence, exploring alternative means of communication is not only important but may also help towards mitigating the risk of security breach in communication channels. In this paper, we explore the possibility of communicating speech and music, over IR channel. Audio communication using an IR transmitter source and atmosphere as a medium is proposed. A prototype communication set-up is designed, in which an optical wireless transmitter using an IR emitting LED acts as a source and a photo-diode as a receiver. The methods Intensity Modulation (IM) and Direct Detection (DD) are used for modulating the signal in transmitter and for demodulation in the receiver, respectively. The Line of Sight (LoS) communication is established between the transmitter and the receiver. Experiments are conducted to measure the transmitter signal range and coverage space, in the terms of Elevation angle (θ) and Azimuth Angle (φ) with respect to distance (r). Measurements are taken for four different Infrared Levels (IL) of IR signal intensity. Each level here consists of a number of IR emitting LED's, placed in concentric circles, as part of the transmitter source. Initial results are encouraging and establish the feasibility of speech communication over IR channel. Results also indicate that range and coverage area of the modulated signal increase by increasing the intensity of Infra-Red light, which is dependent upon the number of IR LED's in the cluster.