Regarding the TSMP58000 Receiver

Discussion in 'The Projects Forum' started by PreethiB, Sep 24, 2015.

  1. PreethiB

    Thread Starter New Member

    Sep 24, 2015
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    A circuit was setup to detect obstacle (proximity sensor) using IR transmitter which uses Arduino to generate 40 kHz Frequency (the frequency was checked using a digital oscilloscope and it displays 40 kHz) and TSMP58000 as IR receiver, but the voltage at the output of the IR receiver when an IR pulse gets detected is seen as 3V instead of a value ~0V .What could be the issue?

    Receiver used - http://www.vishay.com/docs/82485/tsmp58000.pdf (it receives in 20 kHz - 40 kHz range)

    The screen shot of the transmitter and receiver circuits are as below where 4 is connected to the arduino pin and IR led is connected to the ground. External Power supply is used to power the IR receiver. Where common ground is used for both.
     
  2. #12

    Expert

    Nov 30, 2010
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    The way I read this, the output is supposed to be, "high" when it detects the carrier frequency.
    So what's the problem?
     
  3. wayneh

    Expert

    Sep 9, 2010
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    5th bullet point is "Output active low"
     
  4. #12

    Expert

    Nov 30, 2010
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    Bullet point 7 seems to contradict this, thus the confusion.
    No Truth Table provided.
    I ask the Thread Starter: Is the output also high for no signal?
     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Signal output is high until a carrier is present, then its low
     
  6. wayneh

    Expert

    Sep 9, 2010
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    And FWIW, this is the usual behavior of such receivers. There are only a few that work the other way, and they're not easy to find.
     
  7. PreethiB

    Thread Starter New Member

    Sep 24, 2015
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    Yes the output is high for no signal.
     
  8. be80be

    Senior Member

    Jul 5, 2008
    431
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    It don't work like your thinking if you send a steady 40 kHz signal it see's it as noise and will not pull low. gate the signal with 1mS breaks and it should work like you want it to.
     
  9. wayneh

    Expert

    Sep 9, 2010
    12,103
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    Good point. These things will go low when they spot the carrier but will not hold that for long. I'm not sure where this is in the datasheet.
     
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