Need Help on a Digital circuit.....Pls Help

Discussion in 'The Projects Forum' started by famesethu, Oct 25, 2009.

  1. famesethu

    Thread Starter New Member

    Oct 25, 2009
    12
    0
    Hey guys......:)

    I'm new on allaboutcircuits.I need help on my new projects from you guys.
    I've a 3 channel RF remote control system.I remade it from my motorcycle alarm system.:DI found a point on the circuit which can deliver 3 types of trigger pulses.The problem is dat the three types of pulses came from one line (multiplexed/encoded).I need to make a circuit that can convert this one line to three seperate(Demultiplex/decode):confused:

    It gives,
    A Monopulse on pressing Lock button on the remote.
    A 2-Monopulses on pressing unlock button.
    A continous high state for 10sec on pressing siren button.

    [​IMG]


    [​IMG]

    The attached first figure shows the pulse schematics.The second figure shows the required circuit for me(as logicaly schematised)
    Please help.......
     
  2. tibbles

    Active Member

    Jun 27, 2008
    249
    3
    hi fameseth
    one of the clearest submissions ive seen in a long time,
    im a bit new, we have a lot of different time zones so it can take a short while for the experts to answer your query ,

    in the meantime consider the 4017, each output goes high in turn -
    one pulse--- output 1 goes high
    two pulses--- output 2 goes high and so on
     
  3. tibbles

    Active Member

    Jun 27, 2008
    249
    3
    ps
    reset to off after each command, say after 5 seconds.

    the ten second pulse is a problem, ideally if it could be split into 3 somehow,
    a time constant and/or maybe the 555 could do this

    (5/6 second time constant triggers more than two pulses from a 555?-just a thought-)
     
  4. famesethu

    Thread Starter New Member

    Oct 25, 2009
    12
    0
    Thanks for ur reply tibbles...
    Actualy thats wat i want.I want the single line to split into three line.
    Well Can u guide me with this 4017 pinlayouts and truthtables or something if u dont mind?
    It will be a great help.
    thanks pal...
     
  5. tibbles

    Active Member

    Jun 27, 2008
    249
    3
    hi again
    just google 4017 (or its equivilent) plenty of info there.
    basically the clock advances the count and reset resets to zero

    this is just one approach, its similar to a digital proportional decoder,but
    normally you would have more control over the input- sync pulse, frame length etc,where you would use each channel in turn to pass the logic level and length of pulse,

    if i get chance will look again later, hopefully you will have had more knowledgable replies by then.
     
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