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Sniffing out IR remote control codes with a PC

Discussion in 'Electronic Design' started by Steve S, Nov 25, 2004.

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  1. Steve S

    Steve S Guest


    I seem to remember seeing a simple circuit for connection to a PC's RS232
    port and software (DOS/Windows) for sniffing out the codes being transmitted
    by IR remote control handsets. FWIW I'm only interested in sniffing out
    handsets that use the NEC protocol.

    I've Googled for a while, but so far only found circuits that use PICs
    etc. - I'm sure it was done with just an IR receiver and some discrete
    components. If someone knows of something suitable, then could you please
    let me know.

    Many thanks,
  2. Si Ballenger

    Si Ballenger Guest

    The below is about as simple as it gets. The recorded info can be
    saved as a text file for evaluation using the EZ59 software. The
    USB-UIRT is a nothe gizmo that might be of interest.
  3. Steve S

    Steve S Guest

    Thanks a lot Si. The circuits are just what I am looking for (the receiver
    parts). The USB-UIRT looks very interesting too. I've got to check out the
    software since I really want a dump of the NEC codes being transmitted,
    rather than being able to learn them for later retransmission - I wonder if
    the EZ59 software can do this, or how hard it is to decode the raw text
    files? Alternatively, maybe the Girder s/w can when running from the UIRT -
    I'll look into it.

    For anyone's who is interested, I'm going to be zapping it with all the
    settings from a one-for-all universal remote and want to have a record of
    all the NEC customer codes used - we're designing a remotely controlable
    unit and don't want it to clash with any codes already in common use - our
    first unit used a customer code chosen at random, and we found out somewhat
    later that it did clash with some Toshiba TVs! :(

  4. Si Ballenger

    Si Ballenger Guest

    A google search will pull up a lot of circuits. If the baseband
    frequency is ~38khz, you could use an IR decoder (radio shack
    ~$4) to get just the pulses, and vire these using an O-scope
  5. Steve S

    Steve S Guest

    Thanks. TBH I already have a digital storage scope and an IR receiver
    module - I just can't get the codes out without looking at each waveform by
    hand. I might have a go at writing some PC s/w to decode the NEC codes
    coming in via the printer port using one of the circuits you've pointed me
    too (I was just being lazy I guess hoping there was software already done!)

  6. Si Ballenger

    Si Ballenger Guest

    You might go to the below site to see if they already have the
    codes you need.
  7. Ian Stirling

    Ian Stirling Guest

    Alternatively, use the soundcard.
  8. Steve S

    Steve S Guest

    Thanks again for your help - that's a very useful site. Not sure if they
    list all the actual codes anywhere TBH, but I'll check more closely. BTW, I
    came across LIRC (Linux) here
    and WinLIRC here:
    These bits of sotware work with very basic circuits connected to the serial
    port and may well do the job very nicely.

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