simple timed relay to leave power off for 3 hours

Discussion in 'The Projects Forum' started by jillian gregg, Feb 2, 2008.

  1. jillian gregg

    Thread Starter New Member

    Feb 2, 2008
    3
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    Hello,
    I am hoping to convert a personal vending machine (http://www.amazon.com/Koolatron-Vending-Machine-%2d-Red/dp/B000NJBMXC) to only allow access to 1 drink every 4 hours.

    To do this, I'm thinking I would intercept the button wiring with an NC relay/timer combination that will not allow the relay to close for the next 4 hours.

    Any suggestions as to whether this could work and what parts I should buy to make this happen?

    Thanks!
    Jill
    Complete Novice
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    Jill,
    Do you have any wiring diagram of the dispensor?
    Ken
     
  3. jillian gregg

    Thread Starter New Member

    Feb 2, 2008
    3
    0
    Thanks for responding!
    I haven’t taken the machine apart yet - but there is no coin operation. You just press a button and the drink comes out. Hence, I just want to make the button function inoperable for 3-4 hours once pressed. If this is going to be hard, I might prefer to return the machine rather than tear it apart. I was hoping there is some simple part or two that could make this happen. Seems like it would be the opposite of a timer for a toaster oven or microwave. Instead of turning the appliance on for a period of time – it would turn it off. I don’t care if the power to the whole machine is disabled or just the button (which seems simpler). Thanks for any leads!
    Jill
     
  4. nanovate

    Distinguished Member

    May 7, 2007
    665
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    Are you familiar with microcontrollers?
     
  5. jillian gregg

    Thread Starter New Member

    Feb 2, 2008
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    I didn't know what they were called or that you could buy them and program them yourself. Looks like a NC relay and 4 bit microcontroller would do the trick? I have a friend that could show me how to add the program. This seems doable. However, this task seemed so simple that I thought there might be an 'off' timer that one could buy..... similar to security lights but button operated with a manual or digital interface that allows you to control the length of time off since the button was pushed.
     
  6. nanovate

    Distinguished Member

    May 7, 2007
    665
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    There are relays with timers built-in. They are pretty expensive though.
     
  7. tian

    New Member

    Sep 23, 2007
    4
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    I prefer use 555 to Microcontroller. designing with 555 is more hardware oriented, and you don't have to have write any program.

    Use 555 timer as astable multivibrator to build the delay timer.
    If you want to make long delay, use 10 bit counter, 4017 maybe.
     
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