Looking for help on a simple push-button delay design

Discussion in 'General Electronics Chat' started by JerryH, Jan 10, 2011.

  1. JerryH

    Thread Starter New Member

    Jan 10, 2011
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    0
    Hello all, I'm new to this site so I hope I posted into the correct forum.

    I've been trying to locate a sample design that would allow me the following function: Push a button and immediately send an "on" pulse...if I continue to hold down the button for another full second, start sending pulses at about 2/3 times per second until I release the button.

    This kind of functionality is common on appliances, such as holding the Up/Down Channel buttons on a TV remote, or to quickly set a digital clock.

    I get the feeling the ubiquitous 555 would be used in this scenario, but I've just too many gaps in my knowledge. Thank you!
     
  2. #12

    Expert

    Nov 30, 2010
    16,247
    6,744
    More than one 555 (also known as a 556). Let the pushbutton send the first pulse (capacitively coupled) while starting "Timer one", a 555 configured as a one-shot. When timer 1 clocks out in one second, it allows a second 555 to start oscillating at 2/3 Hz.

    Meanwhile, the button did an enable function, so when the button is released, everything stops.

    That's a block diagram. The schematic comes next.
     
  3. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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