Battery Powered Burglar Alarm Circuit
Here’s a design circuit for single
zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off
timers. It will accommodate the usual types of normally-closed input
devices - such as magnetic-reed contacts, foil tape and PIRs. This is
the figure of the circuit;
The alarm is easy to operate. Sw1 can be any type of two-way switch. If the Buzzer sounds when you switch the alarm on - the normally-closed loop is open. Switch off again - and check the building for open doors or windows. If the Buzzer does not sound - the loop is intact. Depending on the setting of R3 - you have up to about a minute to leave the building. As you do so - the Buzzer will sound. When you close the door behind you - it should stop sounding. This confirms that the loop has been restored within the time allowed. When you return and open the door - the Buzzer will sound. Depending on the setting of R4 - you have up to about a minute to switch the alarm off. If you fail to do so - the Siren will sound. Depending on the setting of R5 - the Siren will sound for up to about 20-minutes. Then it will switch off - and remain off. Of course - you can stop the noise at any time by moving Sw1 to the "off" position.
If you are interested in protecting your home with a surveillance system, you should first grasp the concepts of the technology. There are several home surveillance systems to choose from, making it in your best interest to learn all you can. Most of the security devices are not hard to install or monitor - providing you have the right guide to assist you. Good Post Keep it up.
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