TSOP IR receiver help.

  1. well i m designing a simple circuit in which a bulb is turned on and off by a simple household remote control. Normal remote control gives IR of 38 khz so i m using TSOP 1738, there is also an alternative of HRM 3800. Well i m having a problem that neither of them r working. When i press the remote, it doesn't give any voltage change whereas i want at least 4-5volts. Can anyone help me with this by providing some circuit for TSOP which works properly or have any idea, plz share it with me.
     
  2. jcsd
  3. From the datasheet, it looks like the thing gives out pulses corresponding to the IR pulse train from the zapper.

    You may need additional circuitry to achieve what you require.
     
  4. berkeman

    Staff: Mentor

    Post some oscilloscope waveform pictures and your schematic, so that we can be of help.
     
  5. i've posted the complete circuit. Everything is working well except the TSOP part. the voltage doesn't change at all. what can i do now? is there any alternative or is there any way i can connect the TSOP? i m using a normal tv remote control. plz help me out with this guys.
     

    Attached Files:

  6. The other thing that just crossed what passes for my mind is that all zappers are not 38kHz...

    Have you tried it with a different make of zapper?
     
  7. zapper? u mean remote control? i've tried it with tv and vcd remotes but both didn't work at all. i've learned these remotes generally gives 38 khz. how can i test the frequency?
     
  8. berkeman

    Staff: Mentor

    When you trace the receive signal with an oscilloscope, what do you see? Monitor the TX signal at the remote control's IR LED to see what the 38kHz modulated TX signal looks like, and look for a similar signal at the output (collector) of T1 in the RX circuit. What do the waveforms look like?
     
  9. NoTime

    NoTime 1,570
    Science Advisor
    Homework Helper

    Hmmm, The TSOP should strip the carrier and just put out the remote pulse train, if it works like similar devices. So the 100u cap should work as a peak detector and saturate T1 giving a single transition for any key press on the remote.
    With a DC scope probe you should see a DC transition plus a bit of a triangle wave at the output of the TSOP.

    Any chance you simply miss wired the tsop?
    The pinout is different from the schematic layout as the center pin does not go to t1 base.
     
  10. i've seen this datasheet and connected the pin as mentioned here. but still its not working. i'v not yet checked the frequency with oscilloscope which i'll do later when i've the access to oscilloscope. what will i do next?
     

    Attached Files:

  11. NoTime

    NoTime 1,570
    Science Advisor
    Homework Helper

    Looking at the pdf and schematic, you should have 4-5 volts at the output of the TSOP with no remote input.
    It should go to zero when triggered by the remote.
    You can measure this with a DVM.

    Your original post implies that the voltage you have is 0 always.
    If this is so then you have a bad component in the circuit.
     
    Last edited: May 9, 2008
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