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Need Help - Timer to complete circuit

Discussion in 'General Electronics Discussion' started by RevZach, Sep 21, 2018.

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  1. RevZach

    RevZach

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    Sep 21, 2018
    So I built an arcade cabinet using an old CRT TV and one of those "plug and play" PacMan games from the aughties. (It sounds lame, but the way I did it, it looks legit). I wired the unit's reset button to an arcade button/momentary switch on the control panel and everything's working fine, except one thing: after five minutes of Pac-Man demo, it goes into some sort of screen saver mode and cuts the video output (half the point of the cab was that the demo would be going and the marquee lit up whenever we were hanging out in the den). I've found that if I just hit the B button ever couple minutes, it doesn't interrupt the demo and it keeps it from going into screen saver mode.

    I want to wire that button to a timer that will complete the circuit once every two minutes. I'm not great with electronics (I know enough to know that I don't know much) and was hoping to buy something that would do this, but everything I find seems to SUPPLY power on a timer, rather than just completing the circuit. The thing runs on four AA batteries (although I've replaced them with one of these: https://www.amazon.com/gp/product/B076MZT7X3/).

    Any advice? Thanks!
     
    Last edited: Sep 21, 2018
  2. RevZach

    RevZach

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    Sep 21, 2018
  3. AnalogKid

    AnalogKid

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    Jun 10, 2015
    I prefer ebay to amazon, but both have lots of little timer modules. For the same $10, some have a digital display which makes for much more accurate setting of long delay times.

    Lose the batteries. Any little 5V wall wart like a cell phone charger or anything with a USB output jack will work.

    Use the "A" (relay contact form A) or "NO" (Normally Open) contacts on the timer output relay. The terminals are marked "Load Power" in one of the images. Two wires from those contacts go directly to the switch you want to control, either wire to either switch contact (the relay contacts are not polarity-dependent).

    ak
     
  4. RevZach

    RevZach

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    Sep 21, 2018
    Thanks for the reply! Forgive my ignorance, but I'm assuming I plug the black/red deal into the spot marked "5V DC" and normally would attach the batteries there. And you're saying snip the end off a 5V wall wart or USB power supply and attach that to the + and - ?

    (Also, I'e noticed that different wall warts seem to have different amperage output; does that not matter here?)
     
    Last edited: Sep 21, 2018
  5. AnalogKid

    AnalogKid

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    719
    Jun 10, 2015
    The timer board draws very little power, even when the relay coil is activated, so just about any wall wart will work. For the short power cable that comes with the board, red is +5 V and black is GND.

    If you have a universal type wall wart with a jack for a USB cable, then the cord from an old dead mouse makes a great power cable to splice onto the one that comes with the board.

    If your wart already has a long enough cable and you don't mind cutting off the connector (that always makes me pause), then yes, cut, strip, twist.

    ak
     
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