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240v buzzer/sounder

Discussion in 'Electrics UK' started by HERTS P&D, 24 Feb 2021.

  1. HERTS P&D

    HERTS P&D

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    Hi Guys,

    I am looking for a buzzer/sounder of some sort to fit in an exterior junction box wired to a PIR, so that when the flood light comes on so does the noise.

    Any idea guys?

    Andy
     
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  3. Mottie

    Mottie

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  4. JohnW2

    JohnW2

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    It's even IP55! There are also many that appear to be that one (or a close copy) on ebay.

    Kind Regards, John
     
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  5. Harry Bloomfield

    Harry Bloomfield

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    I needed something similar, years ago. My solution was an experimental one, of wiring the supply to the lights through through the primary of a small mains transformer, the secondary I wired to a bridge diode, a capacitor to smooth it, then connect it to a peizo sounder. It supplied three PIR lights and sounded for any or all of the lights being triggered.
     
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  6. HERTS P&D

    HERTS P&D

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    Many thanks guys, at least it is worth £12 just to try out.

    Andy
     
  7. HERTS P&D

    HERTS P&D

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    Just ordered, I'll let you know how I get on.

    Andy
     
  8. Lectrician

    Lectrician

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    That buzzer linked to is intended to go inside an enclosure with a 22mm hole in the front. Assume you realise that?
     
  9. HERTS P&D

    HERTS P&D

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    Yes. (y)

    Andy
     
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  11. JohnW2

    JohnW2

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    It is, but that obviously doesn't mean that it has to be used in that manner. I have a conceptually very similar buzzer, used (outdoors) for exactly the same purpose as Andy wants, but, rather than attaching it to a hole in a panel, it is entirely contained within a weatherproof enclosure.

    For what it's worth, in another part of my garden I implemented the approach that Harry mentioned - a super-simple (3-component) ELV supply feeding a piezo sounder/buzzer). Both of those approaches have been working, without problems or attention, for many years.

    Kind Regards, John
     
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  12. Harry Bloomfield

    Harry Bloomfield

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    My version needed no ELV supply, no actual supply at all. To improve on the detail...

    I basically used an old transformer, which had space around the core to wind a few extra turns. I then wrapped a few turns of the 1.5mm mains, complete with its insulation, feeding my outside PIR lighting. I then used one of the existing windings on the transformer, as my supply. That I rectified, smoothed with a cap, then fed to a piezo sounder, with a built in oscillator.

    I derived the idea, from another system I devised in Wales, in the process of commissioning an experimental hydro scheme. The 240v control panel, was designed to have 240v run out to some large delicate open frame pressure gauges, on the in and out flow pipes. These made contact with the 240v a little too easy - basic idea was if either pressure exceeded limits, it would short the 240v and safely trip the unit out.

    I solved it with the addition of a pair of small double insulated 240/25v transformers, mounted in the panel. 240v side operated the trip relays, 25v went across each pressure gauge contact set. Maximum open circuit voltage at the gauge 25v, short the 25v side and the system tripped out.
     
  13. JohnW2

    JohnW2

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    I think that's really just a 'play on words' - your " 'few turns', rectifier and smoothing" constitute an "ELV supply" much the same as mine - the only difference being that I used a 'dedicated' micro mains transformer, plus a rectifier (single diode or bridge, I can't remember) and smoothing capacitor in order to feed the piezo sounder.

    Kind Regards, john
     
  14. SUNRAY

    SUNRAY

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    Harry is describing a few additional turns as the primary and using one of the existing windings as the secondary to supply the sounder. Effectively a current transformer.
     
  15. JohnW2

    JohnW2

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    Yes, I realise that, but it doesn't alter what I said, namely that both he and I used just three components to 'supply' the sounder - 'a transformer', a rectifier and a smoothing capacitor. The only difference is that his transformer was, as you say, 'current-fed' (using the existing current flowing in his lighting circuit), whereas mine was ('conventionally') 'voltage-fed'.

    The one situation in which Harry's approach would be advantageous would be if there were no neutral available, but that situation is very unlikley to arise, since I would think that any cable carrying his lighting current would almost certainly have both L and N.

    Kind Regards, John
     
  16. Harry Bloomfield

    Harry Bloomfield

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    I think John you are still completely missing the entire point....

    Imagine a circuit, feeding out to several self contained PIR operated lamps. You don't normally have access to the internal switch wire of the fittings, from PIR to the lamp, so you have no means to know when a light has been triggered, except from the current flow in the supply.

    My understanding of the OP's issue was that he wanted to sense when his outdoor PIR light, or lights were triggered, so he would hear some sort of audible alarm indoors. My solution does exactly that, without need to interfere with his existing outdoor wiring at all.

    Your own proposed solution relies on being able to access that switch wire.
     
  17. JohnW2

    JohnW2

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    If that were the situation, then I agree that your approach would be the way to go. However ...
    Ah, there's the issue - "your understanding" and "my understanding" differed. I thought that what he wanted (as I did) was to have a buzzer sound outdoors, in the vicinity of the PIR and/or light, so as to 'frighten intruders off' by the noise (which they might think also indicates that some alarm has been triggered), as well as the light. He wrote...
    ... which, particularly given the reference to an 'exterior junction box' (and a single flood light), and the fact that he was asking for a "240V buzzer/sounder", led me to believe that his requirement was the same as mine, as described above (and that he would have access to S/L and N at his JB). Maybe I misunderstood.
    It would, if that was what the OP wanted/needed.
    It would, and I had thought that such would probably be available at the OP's 'exterior junction box', but I may be wrong. If that's not the case, then your approach would clearly be a way to go, but it would require that the OP was comfortable with implementing it. If there is, or could be, a S/L and N at his JB, then to simply use a 'mains' voltage sounder, such as has been illustrated (and is what he had been asking about), would presumably be the simplest course for him.

    Kind Regards, John
     
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