IR receiver problem it will only blink

Discussion in 'General Electronics Chat' started by 74266, Sep 13, 2016.

  1. 74266

    Thread Starter Member

    Mar 20, 2016
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  2. AlbertHall

    Well-Known Member

    Jun 4, 2014
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    I suspect this is a function of the TSOP. It expects a 38kHz modulated signal not a continuous 38kHz.
    Try using another '555 running much slower with its output connected to the reset pin of the transmitter '555.
     
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  3. 74266

    Thread Starter Member

    Mar 20, 2016
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    Do you mean I add a 555 timer in my receiver then connect the VO of the TSOP and reset pin of the 555

    also instead of TSOP1738 I use HS0038
     
  4. AlbertHall

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    Jun 4, 2014
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    The extra '555 should be in the transmitter so the 38kHz is switched on and off repeatedly.
    The following is from the HS0038 datasheet:
    The data signal should fullfill the following condition:
    • Carrier frequency should be close to center frequency of the bandpass (e.g. 38kHz)
    • Burst length should be 10 cycles/burst or longer.
    • After each burst which is between 10 cycles and 70 cycles a gap time of at least 14 cycles is neccessary.
    • For each burst which is longer than 1.8ms a corresponding gap time is necessary at some time in the data stream. This gap time should be at least 4 times longer than the burst.
    • Up to 800 short bursts per second can be received continuously.
     
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  5. AlbertHall

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    I just noticed this in the datasheet. Note that the second item here is what you are attempting.

    Some examples for such disturbance signals which are suppressed by the HS0038B are:
    • DC light (e.g. from tungsten bulb or sunlight)
    • Continuous signal at 38kHz or at any other frequency
    • Signals from fluorescent lamps with electronic ballast with high or low modulation (see Figure A or Figure B).
     
  6. ci139

    Member

    Jul 11, 2016
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    IR-Receiver-Circuit-Diagram.gif.png tsop48.pdf.p2.png
    so the BC557 is PNP - on their circuit set up with gain of 1 Ie=Ic+Ib , Ib=Ic e.g. doubling the base current for "emitter" that is now collector - and the "collector" current is approximately that of the base current . . .
    if i look the tsop38 ds i assume OUT goes high cancelling the BC557 - besides the simple supply filter R1 C1 - shown on ds is omitted on CircuitDigest's v - i would email the author of this article and asked him - why it's good that way (theres alway smth. good for smth.)
    ... !Google ...
    1738 this time
    TSOP1738 38 kHz.png
    [​IMG]
     
    Last edited: Sep 13, 2016
  7. 74266

    Thread Starter Member

    Mar 20, 2016
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    Thank you can you please list the pins I should connect in the another 555 timer

    so I also need to avoid other light disturbance for this?
     
    Last edited: Sep 13, 2016
  8. AlbertHall

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    Jun 4, 2014
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    The TSOP output is active low, so the receiver circuit should use a PNP transistor, but there is an error in the circuit diagram - the base and collector are swapped.
     
  9. AlbertHall

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    Jun 4, 2014
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    The second '555 should have the same components connected to it except that C1 should be 47nF. Pin 4 of the original '555 should be disconnected from the supply and connected to the Q output of the additional '555.
     
  10. 74266

    Thread Starter Member

    Mar 20, 2016
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    what do you mean by the pin 4 of the original '555 should be disconnected from the supply and connected to the Q output of the additional '555 what will happen to the switch and IR LED
     
  11. AlbertHall

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    Jun 4, 2014
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    No. The IR receiver will do that for you.
     
  12. AlbertHall

    Well-Known Member

    Jun 4, 2014
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    The original '555 has pin 4 (reset) connected to the supply voltage. It should be disconnected from the supply and instead connected to pin 4 (output) of the new '555.

    The switch and IR LED remain connected to pin 4 (the output) of the original '555.
     
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  13. 74266

    Thread Starter Member

    Mar 20, 2016
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    thank you for this
    also sorry but I made a mistake I thought you want me to disconnect the Q of the original 555 so I just need to disconnect the pin 4 original 555 from supply and connect it in the pin 4 of the new 555
     
  14. AlbertHall

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    Jun 4, 2014
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    Sorry, I mis-triped that. It should be:
    I just need to disconnect the pin 4 original 555 from supply and connect it to pin 3 of the new 555
     
  15. 74266

    Thread Starter Member

    Mar 20, 2016
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    Okay I will try this but can I ask if it is possible for example if I only tap the tact switch of transmitter the receiver will permanently go to ON MODE and if I tap it again it will permanently go to OFF MODE our professor told us that it is possible using IC 7486 and 7474 but he won't say it how so I want to ask if this is possible?

    if so can you please elaborate on how will I do it because I need this kind of function because this time he want us to put the IR receiver to any electronics and the one I want to use is RADIO but it has a condition that will only function when you use 3V only.
     
  16. ci139

    Member

    Jul 11, 2016
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    74HC86 74HC74 NXP
     
  17. 74266

    Thread Starter Member

    Mar 20, 2016
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    I finally made it work what I just did is I made my ir receiver more simple I only used TSOP and an led with a resistor
     
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