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Trigger 'AV In' button on portable dvd player

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  • Trigger 'AV In' button on portable dvd player

    Hi there. Yes im a newbie, but I dont think this qualifies as a newbie question. I am going to use a Portable Dvd player as my screen (yes I know its **** but really tight budget ) which has an av input, but to switch to the input, the av button needs to be pressed each time its turned on. I wasnt going to have the screen in the case, was going to hack it down, hence no button pad. I have isolated which pins on the plug to the buttons which need to be shorted to simulate the button press. Each pin has about 3 volts when they're not connected, and they drop to .6 when they are shorted. I was thinking I could use a relay to short them, but the input doesnt change until the button is released.

    Can you get some sort of 'momentary switch' type of relay?
    Does anyone know how i could achieve this electronically or using the serial port of my pc?

    Thanks in advance

  • #2
    A common issue around here is how to get a VGA touchscreen monitor to auto-power on every time you turn the key. There are a couple solutions to this, one of which may apply to your DVD screen.

    1. Reprogram or Recode the screen's software to do this.
    2. Use a simple resistor/capacitor circuit directly on the button circuit:

    3. Use a resistor/capacitor circuit to make a relay into a momentary relay:

    - uses a circuit described at

    Good Luck.
    ** Denotes an "in car" post
    In-Car posts made from passenger seat - Be safe, Don't Post and Drive.


    • #3
      Thanks mate.
      Yeah just last night I found that 12volt page and I was going to try the momentary relay, but just now I have broken my screen

      Thanks anyway for you help