Security System Based on Ultrasonic Sensor Technology

Abstract

In this paper we design and implement a security system with an ultrasonic sensor module to enhance the system's reliability. The ultrasonic sensor contains a transmitter and a receiver and the module is placed in a rotating motor. It is assumed that an ultrasonic sensor is set in a rotating motor to cover a wide range. The Ultrasonic transmitter periodically emits ultrasonic signals into an open area. A rotating motor is used to allow the sensor to cover whole 360 degrees. If the signal ever hits any physical objects, it will be reflected back and the receiver part of the sensor will then capture it. The microcontroller unit (MCU) will constantly check for the receiver output of the ultrasonic transmitter. If the receiver output is high, the MCU will perform distance analysis of the object from the sensor using the fact that ultrasonic waves travel in air at 340m/s. The time taken for the waves to hit the object and return can be calculated as the time taken for the receiver output to be high after the transmitter has been initiated to send ultrasonic waves. Once the distance is calculated, MCU checks whether the object is within the range threshold specified within the MCU for initiating the alert. If the object is within the range threshold, the MCU initiates a sound alarm and also the global system for mobile communications (GSM) modem to send short message service (SMS) or call to the concerned person. Keywords: GSM Module,Microcontroller unit(MCU),Motor controller driver unit,Ultrasonic sensor(obstacles detection). I. INTRODUCTION We were inspired to build a Security system based on ultrasonic sensor technology. Security is an important part of home, banks, shops and so on. The traditional security systems based on opening of doors and windows. Our ultrasonic sensor technology is used, it detects the intruders on their physical presence. An ultrasonic sensor can measure the distance to an obstacle within its conic beam. The AVR family microcontroller was used to interface with the ultrasonic sensor. Here we used Atmega16A microcontroller. The key features of Atmega16A microcontroller that we used for this paper are the three timers and the serial rs232 USART. The timers are responsible of scheduling periodical execution of various tasks, generate alarm tone, and generate PWM signal with appropriate duty cycle and frequency to control the motor. Also, use the motor drivers and it acts as current amplifiers since they take a low current control signal and provide a higher current signal. The range of the ultrasonic sensor can be changed by using an external adjustment device. Fig.1 shows the logical structure of Security system based on ultrasonic sensor technology.