PIR portable alarms

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Smitty
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PIR portable alarms

Post by Smitty » Wed Jan 22, 2003 7:25 am

Hi,<p>I have purchased a few PIR portable alarms to protect a home that is being built. It is powered by a 9 volt battery and will sound an ultrasonic transducer when activated. What is the easiest way to interface a battery powered light when the alarm sounds? The lights are like those push-on closet lights you see advertised on TV. Thanks in advance for any help you can provide.<p>
Smitty

ampedtech
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Re: PIR portable alarms

Post by ampedtech » Wed Jan 22, 2003 9:02 am

Smitty,
I do not know what “PIR portable alarms” are, but I do have a recommendation.
If you are in the build process on your home NOW is the time to hardwire ANYTHING
that you may even think you may even remotely want. Alarm stuff is typically low voltage and therefore escapes the requirement for code inspection. If the sheet rock is not up yet consider wiring for closed circuit video, alarms, tv cable, and intercoms. I know wireless stuff is hot right now but, hardwire is incredibly secure (no one driving around the hood can pick up your signal) and it’s cheep.
hope your having fun with it!

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Edd
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Re: PIR portable alarms

Post by Edd » Wed Jan 22, 2003 10:49 am

Smitty:<p>“and will sound an ultrasonic transducer”
Hopefully those Passive Infrared Radiation detector units are in reality, activating a piezo-electric transducer in the AF range, or only your animals will know for sure. Without reverse engineering evaluation of the output drive circuitry I could only guess the drive and levels there. One could expect an~ 2kc drive to the transducer unit unless its self generated/driven.One could initially try a low current consumption LED at that point……if no go then one could either use that signal to the base of a one xstr ckt with the LED as a load in its collector output circuitry with its appropriate curr lim res. If that doesn’t do it take the AF thru an isolation capacitor to a 1N4148/914 rect to get DC feed to the xstrs base.If a current hog of an incandescent lamp is utilized the xstr may have to be beefed up to a heftier unit or a small sig…2N2222….might have to be used to make a Darlington configuration to make up for the lower Beta of the power xstr.<p>
73's de Edd
[email protected].......(Interstellar~~~~Warp~~~~~Speed)
[email protected]...(Firewalled-Spam*Cookies*Crumbs)<p>[ January 22, 2003: Message edited by: Edd Whatley ]</p>

Smitty
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Re: PIR portable alarms

Post by Smitty » Thu Jan 23, 2003 3:20 am

Thanks EDD and Digitech. Digitech, these are ONLY temporary alarm units used while building the house, for any trespassers, thieves, etc...I have alot of $$$in materials laying around. I also hooked up a temporary phone line that calls out a fixed number when it hears noise. Works real well, and when it calls, it opens a microphone so I can listen to what is going on. I'm having a permanent alarm system hardwired.<p>Smitty

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Edd
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Re: PIR portable alarms

Post by Edd » Thu Jan 23, 2003 3:54 pm

Smitty:
I figured in as much that either you, or a co-operative neighbors house was in eyesight of the jobsite.Its a pity that you hadn't already
commited on the sensors, for while I was perusing the stock at Wally-World (Wal-Mart) I
noticed that they had some closet lights that were battery (4 AA's) powered, built just in the order of the "Push Lights" you described BUT
PIR circuitry was incorporated also. Install the unit in the closet and when you open the closet it detects your hot little body and the light comes on. This would have been exactly what you
wanted in the first place. To top it all, they were on sale for $6.00 each.<p>73's de Edd
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haklesup
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Re: PIR portable alarms

Post by haklesup » Thu Jan 23, 2003 6:06 pm

The easiest way, assuming you don't want to buy something different would be to replace or somehow parallel the beeper with a relay. You may need to boost the signal meant for the beeper with a transistor so you have enough current to pull in the relay. An FET solid state switch would probably also work as well as a relay. Once you have the relay contacts you can put anything you want out there. Try to measure the voltage with respect to ground on the legs of the transducer while beeping.<p>Now X10 makes a few different PIR sensors that will send an RF signal to a reciever module, that in turn can turn on a lamp(s), alarm, digital camera etc. Of course if the thieves/vandals catch on, they could bring along a remote control and disarm it. Don't use house code A and you slow them down. The X10 related security products add a layer of coding for privacy but can do mostly the same stuff including call you on the phone or beeper.

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