voltage activated switch with timer

Discussion in 'The Projects Forum' started by dmanoukis, Jul 27, 2009.

  1. dmanoukis

    Thread Starter New Member

    May 29, 2009
    Hi all, desperate for help to design a circuit that can work seamlessly with an existing light sensing circuit. Basically the output from the photosensor is anywhere beyween 1-6vdc. I need help to design a circuit that will monitor the sensors output without interfeering with the stock module and be triggered on when the voltage is greater than 4vdc. The catch is that the voltage must remain over the threshold for more than 4sec before the output is switched. Any advice would be great. I am a little bit of a newbie, but can read schematics and assemble. Also, supply voltage is 12vdc.