Delayed or locked out push buttons

Discussion in 'General Electronics Chat' started by Aurbo, Jun 15, 2005.

  1. Aurbo

    Thread Starter New Member

    May 6, 2005

    Using 2 momentary buttons to trigger 2 separate events( circuits)

    Both should not be able to trigger the circuits at the same time.

    What could I use to prevent the second button from triggering its circuit until the first button circuit is complete.

    1 button triggers a voice recording that lasts for 120 seconds.

    the second button does the same but in a second language.

    I need to prevent both from playing at the same time.

    I'd rather not have to use a slide switch to select language THEN press the play button


  2. thingmaker3

    Retired Moderator

    May 16, 2005
    The attachment I've added to this post shows a basic lockout circuit. With both switches open, output from gates A and B are both low, and outputs from gates C and D are therefore forced high. If S1 is closed: gate A output goes high allowing gate C output to go low - this will hold gate D output high for as long as S1 is closed. The opposite condition occurs if S2 is closed before S1.

    I suspect it would be easy to add a 120 second "one-shot" to both inputs, or to gate the inputs via feedback from furthur down line.