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Thread ID: 58847 2005-06-14 05:33:00 PIR motion sensor sam m (517) PC World Chat
Post ID Timestamp Content User
363771 2005-06-15 02:22:00 You will have to open up the actual head unit. the wires you are talking about are the 230V ones.

Open up the sensor head and you should see 2 boards. One where all the big wires come off, and another containing the small round IR detector itself. DO NOT put your finger on the clear face, even though it is tempting. If it is like the majority I have seen inside, then you will find those three "same coloured" wires I talked about in my original post.

The next challenge is to figure out which connections are + , - , sensor detect output. Once that is sorted, you will find you have the low-voltage detector you are after. As all the other board does is drop the voltage from 230Vac to 8-12Vdc , and also has the relay which the sensor uses to connect the 230Vac to the lights.
pheonix (36)
363772 2005-06-15 03:29:00 The "mains" board will have a relay (which is used to switch the mains to the lights), and a small transformer. The transformer and its associated diodes and capacitor provide 12V DC to the sensor board.

If you feed 12V to the board, it will drive the (12V DC) relay coil with a transistor when the sensor triggers.
Graham L (2)
363773 2005-06-15 04:22:00 Sensor (sal.neoburn.net)

If at all possible what I want to know is how do I feed 12v to it to activate.

The next step will be connecting to another device (not yet found).

thanks
sam m (517)
363774 2005-06-15 04:56:00 If it's all on one board, look for an electrolytic capacitor, which is connected to either a couple of diodes, or a bridge rectifier. Connect your 12 V to the capacitor's leads, with due respect for polarity. The diodes will stop the 12V from burning out the transformer secondary. Graham L (2)
363775 2005-06-15 23:34:00 The problem being that these are cheap and don't use the conventional transformer arrangement. They use a capactive/resistive divider network to get the lower voltage.

If you want, I can sort it out for you. Just PM me if you want for contact details.
pheonix (36)
363776 2005-06-16 08:40:00 Thanks for the offer Phoenix.

I might be biting off more than I can chew.
What I want is something that does this (www1.jaycar.co.nz) (but not the door chime) but connects to one of these (www.ecomist.co.nz). This is just a rough idea of what I want to do. Basically it is to deter cats from coming onto my property. Not sure what the spray part will be but I heard that cats dont like citrus smell so that will be a start. The sensor I have now sounds like too much work. I want to do it on the cheap as I am not sure if it will work or not.
sam m (517)
363777 2005-06-16 08:48:00 No problems, only cost you the postage to me.
I can attach 2 wires to it for the battery , and use the existing relay to turn on whatever you want. I'm very happy to help you ,so you can have a play safely with low votages.
With faults just requiring the changeout of boards these days, i don't get to use my skills at component level these days.
pheonix (36)
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