Security alarm system using Arduino Uno R3 microcontroller, Ultrasound sensor HC-SR04 and Arduino IDE 1.6.8. Applications of this system ranges from security systems like automated-safe security systems to car parking systems, Work on a simple system where the distance of object is measured from the ultrasound sensors and if any object is in the hazardous range then the buzzer goes on. The intensity of sound keeps on increasing as the obstacle approaches near to the ultrasonic sensors. This feature makes them an appropriate system to be embedded in cars and automobiles for parking measures as it will help determine the distance from obstacles.