Headphone Amplifier with IR Communication

Figure 1 

This low cost project can be used to reproduce an audio from TV without creating any disturbance from other people.

No wire will be used by the circuit between the TV and the headphone because instead of using wires, it utilizes the invisible infrared light for the transmission of audio signals from the TV going to the headphone. The range that can be covered can reach up to 6 meters without using any lens but if required, the range can be made to extend with the use of lenses and reflectors with transmitters and receivers that comprise the IR sensors.

Two series connected IR LEDS are being driven by the two-stage transmitter amplifier that uses the IR transmitter. The audio output from TV to the IR transmitter is coupled by using an audio output transformer that is reversely connected. The audio signals are amplified by the transistors BC547 & BD140. These audio signals are received from TV through the low output impedance windings for TV connection of the audio transformer while high impedance for IR transmitter connection.

A 9V source can power the IR transmitter with the LED functioning as power-on indicator.