Converting AC doorbell to wireless

Discussion in 'General Electronics Chat' started by Omitav, Mar 4, 2016.

  1. Omitav

    Thread Starter New Member

    Mar 3, 2016
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    0
    I currently have a simple AC 230v doorbell at home - press of button at the door delivers 230v to Bell. I'd like to use a cordless Bell switch outside but the problem is that I don't want to replace the recessed wall button on the wall next to the door, none of the cordless switches fit the niche out even give a strong wireless signal when placed in the wall niche. So instead, I would like to try and place the cordless switch inside the house (basically replace the current Bell with the cordless switch such that

    Switch pressed at door -> triggers wireless switch -> wireless Bell rings in another part of house

    This would also allow me to extend the range of the bell without having to rewire the whole house.

    The problem is that the wireless switch works off a 3v circuit while the current switch delivers 230v, so I think an opto isolated trigger mechanism would be best. Would anyone have a simple yet reliable circuit that I could use?
    Thanks in advance
    Omi
     
  2. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,132
    267
    Buy a small 5V wall wart power supply, (connect to the 220VAC bell circuit) connect the output via opto-coupler to the wireless bell input.
    Depending on the wireless transmitter type, you might regulate it down to whatever the battery voltage is, then it can power the transmitter directly, just short the button switch so it's always pressed.

    This is a safe and simple way to interface between high voltage mains and other circuits.
    You may want to add a "bleeder" resistor to the 5V power supply to make it drop out faster after the power is cut.
     
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  3. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
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    A 230 V door bell doesn't sound right. Most wired doorbells were like 16 VAC with a transformer somewhere in the system.

    Low voltage e.g. thermostat wire would be used for connections.
     
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  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,546
    1,252
    Agree. 230 Vac house wiring does not mean 230 Vac doorbell voltage (or furnace thermostat voltage either). Both typically are powered through small power transformers, and run on that low voltage AC rather than DC or high voltage AC.

    It isn't clear from your description whether or not you have direct access to the original doorbell button and its wiring. If so, you can open up the wireless doorbell sender (button unit) and attach the house button in parallel with its built-in button. Photos of the wireless sender (assembled and opened up) would help immensely, along with links to wherever it came from.

    ak
     
  5. KeepItSimpleStupid

    Well-Known Member

    Mar 4, 2014
    1,149
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    My house:

    Recessed button that I modified to be lighted with a LED.
    Transformer in the basement - If you didn't put it there, you would not know where it is.
    Bell in the hallway.

    The transformer is about 1/2 way between the bell and the button. Power provided by an existing light junction box in the basement.

    Thermostat wire connects them. You can't do that with 230 VAC.

    At one point we had a wireless device that would repeat the doorbell to a battery operated chime (D cells) until it broke.
     
  6. Omitav

    Thread Starter New Member

    Mar 3, 2016
    3
    0
    I love it! Simple, and doesnt require me to modify any circuitry (expect the short of course). Thanks Sensacell, i will try this one out.
     
  7. Omitav

    Thread Starter New Member

    Mar 3, 2016
    3
    0
    You're right - it's a bird-bell with a chirping sounds, and it does step down the voltage within the bell. But my biggest problem is not the voltages, its rewiring the house to accommodate the bell in a new location (which I may want to change with a bit of trial and error in order to find the best location). The wireless bell solves the problem and will need no rewiring.
     
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