Burglar Alarm System Circuit - Electronic Circuits Projects Diagrams Free

johno · 18th March 2006, 08:10 AM

I am trying to find a pulse stretcher circuit that will enable the use of barrel type alarm system vibration semsors to operate the zone input of an alarm panel.

The circuit should have adjustable sensistivity for the sensor and operate a relay for a second or so.

Any help would be appreciated

19th March 2006, 05:01 AM

Hi,
How about configuring a 555 as a "one-shot" and outputting it to a transistor to drive your relay? Or a logic level MOSFET or SCR instead of a relay? Whats a "barrel type" alarm??

johno · 19th March 2006, 11:08 AM

Thanks for the reply,

A barrel type vibration/inertia sensor is a device with a small gold plated ball sitting on two pins. When the window is hit the ball jumps up and opens the circuit.

The problem is that most alarm system zone inputs can't detect the short interval that the ball jumps.

I have tried a 555 pulse stretcher circuit but you have no sensitivity control, one break activates it, more or less.

There is a circuit posted using a 4081 IC (July 25, 2002) but it's intended to interface into the designers main alarm system panel and i'm not sure how to modify it to suite other alarm panel zone inputs.

Any help would be greatlly appreciated.

Johno.

Russlk · 19th March 2006, 03:17 PM

You don't want one break to activate the alarm, so how many breaks should it take to activate?

spuffock · 19th March 2006, 04:02 PM

Please learn how to program little PICs, one would make this job so easy!

Russlk · 19th March 2006, 05:35 PM

Easy for Spuffock to say, I have been trying to program a PIC for weeks now; if I had done it with 555s it would be done by now.

**Nigel Goodwin** · 19th March 2006, 05:54 PM

Quote:

Originally Posted by Russlk

Easy for Spuffock to say, I have been trying to program a PIC for weeks now; if I had done it with 555s it would be done by now.

I've always said, and I'll say it again, you need a reasonable knowledge of assembler to use a high level language effectively - your problems stem from having no idea what you're actually doing, because the compiler insulates you from the hardware.

Russlk · 20th March 2006, 01:27 AM

Right on, Nigel. When I look at the assembled file, it makes no sense. Even tho two files are identical up to a point, one works, the other doesn't.

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18th March 2006, 08:10 AM	(permalink)
johno	Burglar Alarm System Circuit I am trying to find a pulse stretcher circuit that will enable the use of barrel type alarm system vibration semsors to operate the zone input of an alarm panel. The circuit should have adjustable sensistivity for the sensor and operate a relay for a second or so. Any help would be appreciated

19th March 2006, 05:01 AM	(permalink)
hyedenny	Hi, How about configuring a 555 as a "one-shot" and outputting it to a transistor to drive your relay? Or a logic level MOSFET or SCR instead of a relay? Whats a "barrel type" alarm??

19th March 2006, 11:08 AM	(permalink)
johno	Burglar Alarm System Circuit Thanks for the reply, A barrel type vibration/inertia sensor is a device with a small gold plated ball sitting on two pins. When the window is hit the ball jumps up and opens the circuit. The problem is that most alarm system zone inputs can't detect the short interval that the ball jumps. I have tried a 555 pulse stretcher circuit but you have no sensitivity control, one break activates it, more or less. There is a circuit posted using a 4081 IC (July 25, 2002) but it's intended to interface into the designers main alarm system panel and i'm not sure how to modify it to suite other alarm panel zone inputs. Any help would be greatlly appreciated. Johno.

19th March 2006, 03:17 PM	(permalink)
Russlk	You don't want one break to activate the alarm, so how many breaks should it take to activate? __________________ see my website: www.geocities.com/russlk

19th March 2006, 04:02 PM	(permalink)
spuffock	Please learn how to program little PICs, one would make this job so easy!

19th March 2006, 05:35 PM	(permalink)
Russlk	Easy for Spuffock to say, I have been trying to program a PIC for weeks now; if I had done it with 555s it would be done by now. __________________ see my website: www.geocities.com/russlk

20th March 2006, 01:27 AM	(permalink)
Russlk	Right on, Nigel. When I look at the assembled file, it makes no sense. Even tho two files are identical up to a point, one works, the other doesn't. __________________ see my website: www.geocities.com/russlk