AN ULTRASONIC OBSTACLE DETECTING ROBOT

An ultrasonic range finder is a device used to detect the range at which any obstacle is present by sending ultrasonic impulses towards the obstacle. Ultrasound is a type of transverse mechanical sound wave with frequency higher than upper audible limit of human hearing which means no human being could be able to perceive ultrasound. Their frequency limit is approximately 20 kHz to several higher GHz. These waves are generally used in RADARs and SONARs to detect incoming objects. In this robotic project, named R2, I have used an ultrasonic range finder present on a robot to detect incoming obstacles along its path. The microcontroller used in making the robot is Arduino Uno R3 processor. The different components used in it are an ultrasonic range finder HC-SR04, an Arduino Uno R3 microprocessor, a motor driver circuit and a 12V battery. The HC-SR04 has 2 ultrasonic speakers out of which one is the transmitter and the other is the receiver. The transmitter also known as the trigger pin is used to transmit ultrasound which strikes any obstacle coming in its path. After striking the obstacle the ultrasound gets reflected towards the source which is received by the receiver called the echo pin. We know that the speed of ultrasound is same as that of sound which is 330 meters per second. The purpose of HC-SR04 is to know the time delay between sending and receiving ultrasonic waves. Thus we know the time period and we know the speed, so we can be able to calculate the distance by using the formula: Distance = [(Speed x Time)/2]. We divide it by 2 since the ultrasonic wave travels the distance twice, once when transmitted and twice when received. Thus the ultrasonic range finder is used to detect the distance at which an obstacle is present. Now the controlling unit of the robot is the Arduino processor. The Arduino is so programmed that when any obstacle is present at a distance of 50 centimetres or closer the robot will take a right turn and move away else the robot moves straight forward. The power source of the robot is a 12V battery and 5V is maintained by the voltage regulator LM7805. Hence the robot works as such.