Tricky Timed Relay Trigger Driver

Discussion in 'The Projects Forum' started by inphaseprod, Aug 1, 2008.

  1. inphaseprod

    Thread Starter New Member

    Aug 1, 2008
    I like that thread title. It's catchy.

    I have a digital timer/relay that will turn on a 12-13.5 volt dc power supply
    which will drive; 1). a T-amp, 2). a small motor 3). an mp3 player (via a
    voltage divider).

    I need a circuit which, when supplied with voltage via the timer, will trigger a small reed relay with a succession of controlled pulses...
    (ON for 2 seconds, OFF for 2 seconds, ON for 2 seconds, OFF for 2 seconds,
    etc. and then STOP RETRIGGERING). This circuit will turn on the MP3
    player. I can't figure out how to make the retriggering on the 555 to stop
    as I'm a bit of a hack. Is it possible to use the audio signal output of the
    MP3 player to interrupt the 555 pulsing?

    Let me know if this will be possible or will I need to get into programmable chips and such? I may just go the route of portable CD
    player as they have simpler triggering sequences to start (e.g. press play).

    Thanks so much.
  2. bertus


    Apr 5, 2008

    If you know how many times it should go on and off, you could make a counter that will stop the sequence.
    The idea is a start / stop flip / flop.
    You start the sequence , count and stop the sequence.

  3. mik3

    Senior Member

    Feb 4, 2008
    Yes you can amplify and detect the MP3 audio signal to stop the 555. Also, you can use another 555 which will make a certain delay time and then inhibit the the other timer by changing the signal on pin 4 from high to low.