Each zone uses a normally closed contact. These can be micro switches or standard alarm contacts (usually reed switches). Zone 1 is a timed zone which must be used as the entry and exit point of the building. Zones 2 - 5 are immediate zones, which will trigger the alarm with no delay. Some RF immunity is provided for long wiring runs by the input capacitors, C1-C5. C7 and R14 also form a transient suppresser. The key switch acts as the Set/Unset and Reset switch. For good security this should be the metal type with a key. At switch on, C6 will charge via R11, this acts as the exit delay and is set to around 30 seconds. This can be altered by varying either C6 or R11. Once the timing period has elapsed, LED6 will light, meaning the system is armed. LED6 may be mounted externally (at the bell box for example) and provides visual indication that the system has set. Once set any contact that opens will trigger the alarm, including Zone 1. To prevent triggering the alarm on entry to the building, the concealed re-entry switch must be operated. This will discharge C6 and start the entry timer. The re-entry switch could be a concealed reed switch, located anywhere in a door frame, but invisible to the eye. The panic switch, when pressed, will trigger the alarm when set. Relay contacts RLA1 provide the latch, RLA2 operate the siren or buzzer.

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hello
my name is toye and i'm a student at a uni in Nigeria, pls i'd like to know if you help me out on a simple project..SMOKE DETECTOR; kindly get accross to me if you possibly can.thank you

 

u damn copycat this is located at http://www.free-electronic-circuits....one-alarm.html and so r lts of other diagrams in this section and they r linked to by the forum anyhow !

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www.rushdenrotaract.org.uk/ - make a difference and have fun !


Never buy "Trust" products, all mine broke !!!

 

What makes you think they weren't copied from here?. The posting date here is 2002, how long have the files been on the other site? - the only indication on 'whois' is that it's a VERY recent domain!.

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Yes, that domain was created on 20/6/2005. Roughly 3 weeks ago! Who's the REAL copycat???

 

oops my appologies but what is going on then can u submit projects to the other site ?

__________________
I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately)

www.simonsphotography.org.uk/ - My other hobby
www.rushdenrotaract.org.uk/ - make a difference and have fun !


Never buy "Trust" products, all mine broke !!!

 

I found my projects copy-catted all over the web, usually at sites that I have never been to before. I don't care if they "steal" my designs because they keep my name on them. :lol:

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hi

i have a question.. u know near by key switch u have a circle.. can u tell me plz what is that.. mean which electronics symbol is that... plz reply me as soon as possible.

thz & regard

Zeshan

 

It's a siren or buzzer, it's mentioned in the text.

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PIC programmer software, and PIC Tutorials at:
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hi

thx 4 ur kind info... just 1 more thing.. u know near by transistor... is it relay again or what :?: .. plz let me know...

thx & regard

Zeshan

 

hi

here is the circuit diagram which i constructed.. circuit diagram enclosed as attachment.

thx

zeshan

Attached Files

5_zone_alarm_system1.doc (75.0 KB, 395 views)

 

Again, the text clearly calls it a relay.

I notice in your diagram you show two relays, why is that?.

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PIC programmer software, and PIC Tutorials at:
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hi

can u have a look on the circuit diagram, i onstructed, to see if i constructed right.

thx & regard

 

hi

i ve constructed another circuit plz have a look n tell me if it is correct..

thx n regard

zeshan
uzeshan@hotmail.com

Attached Files

5_zone_alarm_system_2.doc (68.0 KB, 157 views)

 

I'll ask again, why two relays?.

And why not construct the project as presented?.

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