Idiots guide to build wireless transmitter / receiver

Discussion in 'The Projects Forum' started by Doughnut, Oct 30, 2012.

  1. Doughnut

    Thread Starter New Member

    Oct 30, 2012
    3
    0
    Greetings from the UK :D – Help Please :eek:

    What is required is if the door on an outside porch is opened, a bell will ring inside the home.

    So I was thinking of using, an off-the shelf wireless contact transmitter (from a home alarm).

    And also wireless door bell unit, but how do I make them compatible with each other – an idiots guide would be good

    Any ideas / help / advice will be gratefully received

    Extra notes: I’m a bit of a knob as the name implies when it comes to stuff like this !! :confused:
     
  2. wayneh

    Expert

    Sep 9, 2010
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    It may be simple or it may be impossible. Can't tell without detailed specs. Can you find datasheets for the devices you are considering? You need a receiver and transmitter on the same frequency, at the minimum.
     
  3. Doughnut

    Thread Starter New Member

    Oct 30, 2012
    3
    0
    Wayneh many thanks for your prompt reply

    I can probably get the required spec for the contact switch, but as for the bell idea very doubtful.
    Nothing has been purchased as yet, thought I'd speak to an expert first.

    Or if somebody could recommend a similar devices if they are made, or how I could build one myself 'now stop laughing' :D but the door contact is a must as they are easy to buy and no very inconspicuous
     
  4. wayneh

    Expert

    Sep 9, 2010
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    Ah, well it's very likely you can use the contact switch as a pseudo doorbell switch and therefore you can just slightly modify the commercial wireless doorbell.

    The only issues I see are that the contact switch is likely NO (normally open) whereas a doorbell is NC (normally closed), and it might be a challenge to hack your way into the existing doorbell button to substitute the contact switch.

    (see correction below)
     
    Last edited: Oct 30, 2012
  5. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    I believe you have that wrong, doorbell switches are normally open, and close when you press it.

    Those reed switches they use for home alarms, can be bought in either Normally closed or Normally open, and sometimes you can find them with both sets of contacts.....

    So a Normally closed reed switch will most likely work (Since when it is close to the magnet it will be open) and when the door opens the switch will close to activate the doorbell....
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,103
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    Oh crap, did I write that? It's 180° off of what I meant. Must be my German blood.

    Of course you're right, a doorbell is NO. My security switches are NC, in the sense that they are closed when the magnet is nearby, when the door or window is closed. I suppose you might call that NO, actually. No magnet, it's open.
     
  7. kc5tpa

    Member

    Sep 21, 2012
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  8. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  9. Doughnut

    Thread Starter New Member

    Oct 30, 2012
    3
    0
    Many thanks for all of the input

    Think I'm now on the right track, thanks to the 'Experts' yes that's you lot!! and now have a good idea of what to purchase...

    Will update as / when (time, if I only had more of it) with photos
     
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