4 input select 16 outputs?

Discussion in 'The Projects Forum' started by holabr, Feb 9, 2010.

  1. holabr

    Thread Starter New Member

    Feb 8, 2010
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    I have a 4 channel RF remote and receiver that I would like to use to remotely operate about 8 functions on my car. The receiver has momentary outputs. I am looking for ideas on a simple circuit that would control different functions by using sequential combinations of the channels. For example: maybe pressing channel 1 followed by another press of channel 1 (within a specific time), would activate a relay to lock the doors, and pressing channel 1 followed by channel 2 would activate a relay to unlock the doors. I would like the relay to remain closed for as long as the second channel is held. Then when released, it would reset the circuit to a stand-by mode. Someone suggested that this should be done with a PIC but I think that might be a bit of an over kill. My thinking is that the first channel press would activate a timer on the release of the button. The timer would then hold 1 input high on 4 AND gates. Something would have to now direct all the channels to the other 4 inputs to the AND gates and prevent them from activating there respective timers. I really don't have any experience in digital circuits to design it although I am trying to learn. Can anyone point me to a few circuits that might get me started? Your help is greatly appreciated.
     
  2. mik3

    Senior Member

    Feb 4, 2008
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    This is called a decoder, with 4 inputs you can get 16 different outputs.
     
  3. holabr

    Thread Starter New Member

    Feb 8, 2010
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    OK. How do you build one?
     
  4. mik3

    Senior Member

    Feb 4, 2008
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  5. holabr

    Thread Starter New Member

    Feb 8, 2010
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    I understand the 4-bit decoder but the inputs I would like to be sequential not simultaneous. Don't I need something that latches the first input until the second input is received? Also, how do I build it so the second input doesn't latch itself as it would if it was the first input? Am I missing something in the way the decoders work? Bear with me, I really am trying to do this myself but I have very little background in these types of circuits.
     
  6. mik3

    Senior Member

    Feb 4, 2008
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    You will need a quite complicated circuit and thus it is better to use a microcontroller.
     
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