2005 IRISH SCIENTIST YEAR BOOK

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St. Aloysius School, Cork
Anna Doherty
False alarm proof burglar alarm

My project aims to provide a safe method of avoiding the cost and noise pollution of false alarms in domestic auto-dial alarm systems. The alarm circuit has four triggers which, depending on the order in which they are activated, lead to a final alarm. The four triggers are: the magnet on a door, the infra-red detector and two pressure sensors, one on the outside of a window and the other on the inside.

There are three different states of alarm:

  1. The first state is a light in the house which is intended to show that there is someone stirring in the house. This would hopefully scare away any intruder. This is activated by one of these three triggers: the two pressure sensors and the infra-red sensor.

  2. The second is a preliminary alarm that the people in the house and also, depending on the wishes of the household, the surrounding houses, can hear and/ see. This would make the persons in the house aware of the burglar's presence, which they could affirm and call the Garda� directly. This is activated by two of the three triggers in the above list being set off.

  3. The third state is the auto-dial system which would be activated by opening of the door (magnet) or a combination of three of the above list of sensors. This alarm system is activated by a code on a key-pad.


My Burglar Alarm

If the method of triggering the alarm and the order in which the triggers are to be set off are unknown to a burglar, then the household's safety and comfort should be assured while at the same time reducing the number of false alarms and the associated cost (�2.50 on non auto-dial, �20 on autodial systems).

People feel a greater need for security in their lives today. I hope that the disadvantages in security systems are not too high. New technology and innovations can help this growing industry develop but it's not until people use this new technology that its advantages will be felt. I hope that my alarm design will reduce one of the disadvantages � false alarms, and therefore ensure that home-owners can use their alarm systems to greater effect.

Anna Doherty entered her project in the Senior Section in the Technology Category at the EsatBT Young Scientist & Technology Exhibition in January 2005. She won a Special Award sponsored by Analog Devices. Her teacher was Ms Mary O'Donovan.


This article was sponsored by Analog Devices