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How to build an IR-sensor from scratch?

Discussion in 'LEDs and Optoelectronics' started by perjar, May 17, 2018.

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  1. perjar

    perjar

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    May 17, 2018
    Hi Forum!

    I am seeking some advise about how to build an IR sensor using discrete components instead of the ready out of the box TSOP circuits out there.

    I am using a TSOP 7000 with an Arduino today and it works okay but not great.

    it is a TSOP 7000 because I an capturing and decoding IR signals from a Bang & Olufsen remote and they use a 455 KHz carrier frequency instead of the more common 38 KHz.

    The trouble is the low sensitivity of the TSOP7000 which makes me think I may need to find a new solution. I more or less have to aim the remote diectly at the sensor for it to pick up the signal. It works from across the room but I have to aim it carefully. Compare this to original B&O equipment which seem to be able to pick up the signals no matter in which direction I point the remote. My conclusion is that they are not using TSOP 7000 in their products, or they are able to get them at a much higher quality.

    I have tried a few different TSOP7000 sensors and they are more or less the same I would say.

    So I am tninking I may need to build a sensor from scratch, using an IR diode and discrete components, in order to get better performance. But I have absolutely no idea how to do that to be honest. :(

    Any advise from the forum would be very appreciated. :)
     
  2. BobK

    BobK

    7,682
    1,686
    Jan 5, 2010
    Hmm. I have used standard 38KHz TSOP detectors and I practically had to cover the emitter at the source make it fail, You could point the thing anywhere, from anywhere in the room as long as there was a reflective path to the detector and it would be detected.

    Are you sure you have the correct frequency?

    i think you will have a hard time improving on what at TSOP detector does, they are quire sophisticated.

    Bob
     
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,418
    2,788
    Jan 21, 2010
    I think I could do it with a lock-in amplifier. But I also think it would be rather expensive :)
     
  4. perjar

    perjar

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    0
    May 17, 2018
    Thanks for your advise.

    I have found the root cause finally. It was the power source which was a bit unstable wich caused the TSOP to malfunction. I was using a standard USB charger and apparently they don't deliver a very "clean" output. With a 4,7 uF capacitor in place between Vs and GND everything works perfect now!

    :)
     
  5. BobK

    BobK

    7,682
    1,686
    Jan 5, 2010
    That's more like it! I expect the power supply had high frequency noise in the same range as the 455 KHz operating frequency.

    Bob
     
  6. perjar

    perjar

    3
    0
    May 17, 2018
    Most likely. I will write to Santa and ask for an oscilloscope, it will make life a little easier. ;)
     
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