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131. Dual Tech
motion detectors use two different technologies in the same unit: passive infrared and microwave. These devices are designed to avoid false alarms since both technologies must detect motion before setting off the alarm. Photoelectric Sensors: These sensors project a beam of light across a hall or doorway to detect motion and are triggered when a person passing through interrupts the beam. Glass Break Detectors: Usually mounted near windows to detect the specific high frequency
sound of glass being shattered. They are usually installed on a wall opposite or adjacent to the protected glass and are effective within about 15′ to 25′. Smoke and Heat Detectors: Detect smoke and heat. Chapter II:Our Home Alarm SystemOur Home Alarm System:Our project’s main concern was to build a Home Alarm System using a PIC microcontroller. We started off our project by coding the Keypad, then LCD and the final touch was the sensor. We also added two types of buzzers: one to sound the alarm and the other as a key tone buzzer. The final result turned out to be the following:Figure3.
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