The idea of the project was to create an intruder alert system that senses a subject/intruder within the specified distance. As soon as an object (intruder) comes within the specified distance the Red LED will turn on along the Buzzer, informing of the presence of an intruder. The sensor in this case used is the ultrasonic sensor that is programmed to detect any object that comes within its vicinity in the specified distance and inform the Red LED and the buzzer that turns on the alarm system.

Other components used to build the system comprises of the following list;

Schematic Representation

Circuit Diagram
Schematic Diagram

Final Working Circuit

Circuit Wiring
Ultrasonic sensor in working
As a demonstration, a key card is used as in intruder object with the defined distance of 20cm for the sensor. As the intruder object approaches the sensor within the defined premises, the buzzer beeps to inform of intrusion.