Prevent a door Chime from being activated more than once every 10 secs

Discussion in 'The Projects Forum' started by GUlNNESS, Apr 17, 2017.

  1. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
    34
    0
    Hello Forum users!
    This is my first post ... please forgive me if I make mistakes / waffle on / use the wrong terminology / confuse
    Three sections - Please feel free to skip ... to GREEN

    ITALICS red - Background of my issue
    BOLD green - Project - What I would like the circuit to do
    BLUE - SUMMARY

    Door bell
    I purchased a door bell and the battery soon became depleted fairly quickly, so i decided to use a PSU to alleviate the need to replace batteries
    The door bell broke - the solenoid locked up and would not move
    I bought a new unit and the same thing happened again
    I looked into the issue further and discovered that the doorbell push button had been pushed in at a funny angle and stayed "stuck-in"
    I surmised that the solenoid had been receiving a constant power source and had burnt out
    I was lucky enough to be able to exchange the doorbell unit and used the supplied 9v (PP3) battery
    When the door bell stopped working again, due to another sticking button situation, the battery was dead
    I oiled the doorbell buttons outer edge and was unable to make it stick again - solved!
    I would still like to use the 9v PSU but need to prevent the button, if it sticks again, from frying the solenoid
    Hence this post ...


    I thought that if i bought a 555 timer i could rig up a circuit that would allow a delay in the button pressses
    So far, plenty of people talking about it but no solution ... that I can find

    My QUESTION is thus:
    What circuit would allow the following to take place?
    A guest arrives at the house and presses the door bell button
    The door bell rings
    If the guest presses the button again, within a preset time of 10 seconds, nothing happens
    After 10 seconds have passed, the circuit would allow the door bell to activate
    Each time the button is pressed, one of two things happen
    1 - The door bell rings and the timer starts again
    2 - If the timer is still in the counting state, each button press or continuous depressed state would cause the timer to start again

    SUMMARY
    I have searched high and low but cannot work this out
    I have lots of 555 timers and can obviously get extras parts as and when
    My electronic ability is limited and I am not even sure that what I am asking is possible - although I am a fan of "nothing is impossible - EVERYTHING is possible"
    Thank you one and all in advance for your help
     
  2. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    7,394
    1,219
    Just let the 555 pulse the door bell, use a simple monostable timer circuit, door push operating the 555, and that fires a relay for say two seconds. Use the circuit on the right...


    555mono.gif
     
    absf likes this.
  3. A Homeschoolers Workbench

    Member

    Jul 26, 2016
    143
    28
    You could easily program a Arduino Pro Mini it to do that.:)
    A.H.W.
     
    absf likes this.
  4. crutschow

    Expert

    Mar 14, 2008
    19,496
    5,439
    I'm confused. :confused:
    You were saying you wanted a circuit to ignore a stuck button, but your request is for a circuit that only allows the guest to ring the button no more often then once every 10 seconds.

    Don't you just want a circuit that will provide a pulse to the door bell for every button push, which will ignore the button if it stays depressed?
     
    ebeowulf17 and -live wire- like this.
  5. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
    34
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    Hello A. W. H.
    Very true
    I will amend the OP to reflect ... least cost
    thank you
     
  6. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
    34
    0
    In addition to this ...
    a) I would like it to be 'at least cost'
    b) To avoid solenoid burnout if the doorbell is repeatedly pressed - malicious ringers
     
  7. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
    34
    0
    Hello Crutschow,
    Thanks for the interest ...
    I have placed an amendment ... malicious ringers
     
  8. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
    34
    0
    Hello Dodgydave,
    Thanks for the circuit. Not fully understanding it though
    Is there a breadboard layout?
    I could simulate it on circuits.io ...
     
  9. crutschow

    Expert

    Mar 14, 2008
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    How much current does the solenoid take?
     
  10. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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  11. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
    34
    0
  12. crutschow

    Expert

    Mar 14, 2008
    19,496
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    You will need some way to keep the circuit drain from killing your battery.

    Here's a 555 timer that shuts itself off and draws no current after the 10 second holdoff.
    It generates no more than one half-second pulse in this 10 second interval before it can be retriggered.
    The CD4050 non-inverting buffer provides power to the 555 while it is timing and buffers the half second output pulse generated by R3 and C5.

    upload_2017-4-18_1-26-41.png
     
  13. Kjeldgaard

    Member

    Apr 7, 2016
    270
    97
    If TS can use the following I do not know, but I have for decades had a working doorbell with this circuit:
    IMG_8604.JPG
    It was originally a continuous ringing bell, with the classic breaking contact in series with the coil.
    The operating voltage was initially a 4.5 volt battery, but with experimentation, I found the specified RC component and a 9 Volt block battery gave a sufficiently sound and demanded the button to be released for a few seconds before the bell again could say a single ding.
    Since in fact, nothing else than the consumption from the electrolyte capacitor leakage current, so a battery keep power for years.
     
  14. crutschow

    Expert

    Mar 14, 2008
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    I like that.
    It's simple and should solve both of the op's problems.
     
  15. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
    34
    0
    Hello Kjeldgaard
    I am not great at deciphering circuits ...
    although it may look simple ... i am struggling
    Are you able to do a breadboard layout for me at all please?
     
  16. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
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  17. crutschow

    Expert

    Mar 14, 2008
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    It consists of a resistor and a capacitor.
    The solenoid is the doorbell solenoid.
    The lines are wires and the dots are wire connections.
    What are you having a problem with?
     
    -live wire- likes this.
  18. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
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    AMENDMENT
    So far, thank you everyone for your help
    May I rephrase my project:

    Doorbel button (Simple open/close)
    Ding Dong unit - Powered via a 9v DC PSU
    Timer circuit (e.g. 5 seconds)
    If the timer is not running and the button is pressed the door bell rings and the timer begins
    If the timer is running the bell does not ring
    Each press of the button restarts the timer

    I thinks that's it
    :)
     
  19. GUlNNESS

    Thread Starter Member

    Apr 17, 2017
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    Hello
    Please see the attached breadboard layout
    LHS and RHS
    Both turn on the LED (in lieu of the solenoid)
    Press the button - the LED lights up ... Release the button the LED turns off
    There is not a delay ... What am i missing?
     
  20. crutschow

    Expert

    Mar 14, 2008
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    I'm missing component values and schematics for the two circuits so how can I tell what they are doing?
    (I don't read circuits from breadboard layouts and my psychic abilities are sadly lacking in that area. :rolleyes:)
    (And why are there two circuits?)

    The circuit is designed to provide a pulse to a solenoid, not light an LED.
    The LED lights with the small current going through the resistor, but that small current won't keep the solenoid energized.

    It's not designed to provide a delay when you push the button.
    Why do you think it would and why would you want a delay?
     
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