Question regarding an ON/OFF switch

Discussion in 'The Projects Forum' started by mike_crawford, Oct 21, 2010.

  1. mike_crawford

    Thread Starter New Member

    Jan 21, 2010
    I have an .mp3 player that is powered by a 1.5V battery, and turns on via a pulse type switch. I wish to incorporate it into another circuit that uses an ON/OFF switch that locks and doesn't pulse back.
    In other words when the other circuit is turned on, I need this standard ON/OFF switch to simultaneously pulse my .mp3 player on.

    Is there a simple solution or special switch for this scenario? Would I have to rig some sort mechanical solution to achieve this. Bottom line, I want to control both the circuit and the .mp3 with one unified ON button rather than turn on the circuit, and then turn on the .mp3 player after that.

    Many thanks :)
  2. eblc1388

    Senior Member

    Nov 28, 2008
    You can do that with just 5 components. The U1~U6 is actually inside one single IC.

    When you turns "another circuit" ON, there will be power to that circuit, and I assume it to be anything between 5V to 12V. I called this VDD. Within this voltage range, there is no modification required to the component values.

    The CD40106B IC will also have its power taken from VDD and 0V.

    The timing is at present 0.9s but you can make it longer by changing value of R1 to a maximum of 10MΩ.

    The circuit turns ON the photo MOS relay when power is applied and thus will simulate a "push" of the start button of the 1.5V MP3.

    After 0.9s, the power to the MOS relay is removed and the "push" disappear, just like what you have asked for.

    P.S. If VDD is 12V, you can use a reed relay instead of the MOS relay.

    Last edited: Oct 22, 2010
  3. mike_crawford

    Thread Starter New Member

    Jan 21, 2010
    this is great... many thanks!