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Passive infrared
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Passive infrared

by Willy Willox on Sat Mar 09, 2013 9:15 am

Hi, Am a genuine novice in your dormain.
All I want to do is install a movable outdoor passive on a building site . I want the passive to switch on a buzzer and a light and preferably it can be wireless .
I do live in South africa , so was hoping to be able to make contact with a person in South Africa.

What I need to know is where to get the components and how to connect them up.

I have already connected a buzzer to a Super Market infrared security light ( day light switch incliuded already in the unit ( a standard buy ) and the buzzer i connected to the light wires so that when the light comes on so does the buzzer.

I wish to have more control over the time frame that the light and buzzer are activated for.
I then installed a time switch , also bought over the counter and so the whole appratus only becomes actiated at after 10 pm until 5 am in the morning.

The problem is , one it must be outdoor and two the wind must not activate it.I understand that two passive mounted in parralel willhem prevent this. I need those passives and how to wire to activate the buzzer and light switch.
Any help would be appreciated. Funds are the problem and I can not afford the commercial retailers at this stage.
Cheers Willy Willox
Willy Willox
Posts: 1
Joined: Sat Mar 09, 2013 8:55 am

Re: Passive infrared

by zener on Sat Mar 09, 2013 4:51 pm

Well, first of all I am not in South Africa! But maybe we can get the ball rolling here anyway. I want to confirm that this is all powered by mains power from an extension cord, yes?

So my first question is about this wind issue. How much wind are we talking about here? I was not under the impression that PIR sensors are sensitive to wind. Which way do you have the sensor pointed? I suppose if the ground was warm and the sky was cooler, and the wind made the sensor or stand physically move, then maybe it could trip the PIR. In that case you would need a more stable stand.

In terms of the parallel PIR setup, I have not heard of that, but I am guessing maybe it is like an OR circuit, where the 2 sensors have to agree to get a trip? I know they make some PIR sensors that have 2 zones in them, but I don't remember what the application was for the 2 zone types.

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Joined: Sat Feb 21, 2009 2:38 am

Re: Passive infrared

by zener on Sun Mar 10, 2013 12:30 am

I went to do some research on this and it turns out Ladyada already has a really good tutorial on PIR sensors right here:


So that should teach you quite a bit about how they work.

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Joined: Sat Feb 21, 2009 2:38 am