IR Headset

admin March 7, 2012 21 Comments

Description.

Here is a simple IR headphone circuit that is suitable for listening to TV or radio with out disturbing others. For beginners the IR headset is a better option than FM head sets because they often produce desirable sound quality with out tuning as well as difficult impedance matching that is often done  in  radio circuits which is difficult for beginners.

Transmitter. 

The audio signal is coupled to the base of T1 (BC547) by an audio transformer. The T1 pre amplifies the signal. The transistor T2 (BD 140) drives the IR LED’s which transmit the sound as IR beams. The red LED provides fixed bias for theT2  as well as a power on indication. The transmitter has a 5m range under normal conditions. A 9V battery can be used to power the transmitter.

Receiver. 

The photo transistor T3 receives the IR signals. The collector of IR is connected to base of T4(BC548) which amplifies the signal together with T5 (BC549)to regain the audio signal transmitted. The transistor T6 drives the headphone to reproduce the sound. The receiver can be powered by using a 9V battery.

Circuit diagram with Parts list. 

Infrared (IR) Headphone Circuit
Infrared (IR) Headphone Circuit

Notes. 

  • The audio transformer can be  easily obtained from a old transistor radio. It should be connected with the low impedance winding (thicker) to the audio input (TV or radio) side.
  • The presets VR1 & VR2 can be adjusted for improving clarity.
Comments
  • arun poswal
    April 13, 2015

    Does hs0038 phototransitor work with this set up

  • arun poswal
    April 12, 2015

    Can u tell me which one of t3 or photo transistor is used in this

  • Arun
    March 11, 2015

    i want to know the type of 10k&100k resistors used in the circuit. & working of the circuit.

  • abhi
    December 11, 2014

    please show me the video of this

  • Amith
    September 7, 2014

    i want the value of transformer and and any online(india) stores for these components?

  • chadha
    June 19, 2014

    how can I increase its range upto 50 or 100 meters???

  • circuitlover
    June 8, 2014

    Sir the circuit is just awsome but can we use BC558 instead of BEL 187 because it is not available.

    • Seetharaman
      June 20, 2014

      You can try S8050, BD135, 2N1711 etc NPN medium power transistors. BC548 may not be in a position to handle. BC558 is a PNP transistor of low power, hence cannot be used.

  • Jose nobleza
    March 27, 2014

    I have tried the receiver circuit sir. But it is dostorted… the schematic shows that it used just bc 549 and bd139 but on the detailed it has bc548? Can u clarify it to me

    • Seetharaman
      March 28, 2014

      Since it uses only 9 volt BC149C is most suited but BC148B also can be used. To reduce distortion in the transmitter there is no bias for T1 only with signal it has to conduct means class C operation. Please use a 270K 1/4 resistance between 9volt +ve supply to VR1 & R1 junction (it can be any value between 100k TO 330k till distortion becomes very minimal.)

  • FELIX MALEKELA
    November 23, 2013

    How can I study electronic circuits online?

  • pari
    August 5, 2013

    Does direct sunlight affect this transmitted IRrays??
    if yes then how to reduce that effect??

  • Stein Danneels
    July 8, 2013

    What is the specification of the transformer that you use after the audio signal input?

    regards.

  • Brandon Cooper
    December 12, 2012

    What the approximate range between the receiver and transmitter?

  • Suhrid
    December 27, 2009

    Can you give me more details about the type of photo-transistor and the detailed description for this circuit.

    Thanks

  • har33dik
    July 26, 2009

    can anyone give me the working of the circuit ,which transformmer is used and some theory n application of this project

    • admin
      July 28, 2009

      The transformer used here is a small audio frequency transformer (type no LT700). Such transformers can be easily found on the output stages of old transistor radios).

      I think the description i gave is quite enough.
      I you need a very detailed description, then comment here. I will add it here.

  • mike
    June 17, 2009

    Hi could you please make the pictures clearer thanks mike

  • mike
    June 13, 2009

    Hi could you make the pictures a little clearer as i cannot see what some of the parts are

    thanks

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