IR Receiver Thingy

Discussion in 'The Projects Forum' started by Chris15, Oct 29, 2009.

  1. Chris15

    Thread Starter Active Member

    Apr 15, 2009
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    0
    Hi
    You know those Infrared receivers that have 3 legs and are a small black box. How do i male a switch circuit out of it? i know how to make a relay switch with a LDR but how do i switch a relay on and off with an IR receiver and an IR LED?

    Please help i am puzzled

    Chris
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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  3. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    Actually it is an IR integrated circuit, with demodulator and comparator built in.....

    In the picture you can see a typical block diagram of such an IR receiver. Everything is built into one single electronic component.
    The received IR signal is picked up by the IR detection diode on the left side of the diagram. This signal is amplified and limited by the first 2 stages. The limiter acts as an AGC circuit to get a constant pulse level, regardless of the distance to the handset.
    As you can see only the AC signal is sent to the Band Pass Filter. The Band Pass Filter is tuned to the modulation frequency of the handset unit. Common frequencies range from 30kHz to 60kHz in consumer electronics.
    The next stages are a detector, integrator and comparator. The purpose of these three blocks is to detect the presence of the modulation frequency. If this modulation frequency is present the output of the comparator will be pulled low.


    My .02
     
  4. BMorse

    Senior Member

    Sep 26, 2009
    2,675
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    It would probably be better to use a uc to receive the IR signals from a remote to control a relay or any other output, that way you wont get erronious signals turning your relay on or off.....

    My .02
     
  5. Chris15

    Thread Starter Active Member

    Apr 15, 2009
    252
    0
    Thanks but if u chek my new post i found what im looking for

    Thanks But
     
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