Wireless doorbell to operate and latch a relay

Discussion in 'The Projects Forum' started by bhadresh, Oct 9, 2012.

  1. bhadresh

    Thread Starter New Member

    May 16, 2011
    5
    0
    I'm trying to use my wireless doorbell to switch off my water pump. The problem is how to use the receiver signal to latch a relay. Search the net but no clear solution found !

    I've driven LED from a speaker wire with transistor (doorbell receiver circuit) but don't know how to use this signal to latch a relay. I'm planning to use 6v relay. I've try to drive relay with transistor but no success.

    Pl. have me some idea/schematics.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,986
    745
    what DC voltage are you getting on the speaker terminals when it gets a signal,then remove speaker and test again?
     
  3. johnny_proton

    New Member

    Oct 9, 2012
    2
    0
    quick question.. are you trying to do this to soak people that ring your doorbell? because that would be too funny. :))
     
  4. bhadresh

    Thread Starter New Member

    May 16, 2011
    5
    0
    I did not check the voltage as my multimeter is out of service, but I can run LED. I don't see any possibility to drive relay with these signal as it rapidly on/off. What I want is that how to get this signal to latch it ON state to activate relay until power off.

    :cool: Cool idea :), but not using this for my project. My overhead water tank gets overflow and every time neighbors call me. So trying to implement this idea to switch off my water pump at basement.
     
  5. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
    2,831
    89
    You can use opto isolator...
     
  6. NFA Fabrication

    Member

    Aug 12, 2012
    104
    3
    I am making a latch relay system for something else, and was having some issues. I finally got this to work, and it worked well. The 1000uf cap at the battery may be overkill, but I was having some consistency issues issues, and I just thew a big one on there and it worked great after that. I figure you could just mod this diagram to use your circuit to give a "High" pulse to the other side of the switch in my diagram. The diode by the relay was a 1N4001, and the original diagram I used, had a 4.1K resister to drive the 2N2222, but the closest I had was a 4.7K, and it worked great.

    [​IMG]
     
  7. bhadresh

    Thread Starter New Member

    May 16, 2011
    5
    0
    I finally find the solution. It's on a Ron's site http://www.zen22142.zen.co.uk/ronj/lat.html. I've made changes in this circuit to suit my project.

    Actually it's basic transistor latch, but it was hard for me to understand. After studying and experimenting Ron's circuit, I got the whole idea. Thanks Ron and all member of this forum for your reply/post.

    Here is the circuit that latches a relay. Once I push the doorbell remote button, it stays on until I switch off the doorbell. I'll wire the doorbell remote with float switch and install it on overhead tank. When tank gets full the float switch will on and remote (transmitter) will send the signal to wireless doorbell (receiver) and my relay will activate. Thus it will switch off the pump..

    Eureka...:)
     
  8. NFA Fabrication

    Member

    Aug 12, 2012
    104
    3
    What transistor was used at the signal input? It is not labeled in the diagram.
     
  9. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,986
    745
    use an opto and thyristor,leave the base of the opto unconnected, you will need to switch off the doorbell to reset the relay.
     
  10. bhadresh

    Thread Starter New Member

    May 16, 2011
    5
    0
    It's general purpose NPN transistor, u can use bc547/548 etc. To get the chime voice louder I've add a 1K resistor from the speaker wire to the signal at the base of transistor.

    Optocoupler is good idea, but I've managed without it and it works fine.
     
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