Secured Audio Communication Through Light

Invention of light-emitting diode (LED) brought a great advancement in the visible light communication. LED can be used for transmitting data for short distance in a more economical way with less interference. Present work proposes design and test of a system for communicating audio signal through light. A password-based security feature is incorporated in the system in order to authenticate exchange of information. Proposed system with password communication, password verification and audio communication modules is designed and simulated using Proteus software. Further, the hardware setup is designed and built using LED as the audio transmitter and solar panel as the receiver along with the required amplification and filtering stages. Proposed system is simulated using Proteus software and tested for successful password authentication and audio transmission. The hardware prototype is built and tested successfully for the audio transmission to a range of 90 cm using LED as the source of light. The distance of audio transmission can be extended further by using laser light as source of light.