The Ultrasonic Range Finder

This project is aimed to demonstrate and ensure more understanding on how to use ultrasonic distance sensors to measure distance (without contact) of stationary objects with a moving distance sensor using a stepper motor for movement and plotting the actual position of the objects in real time on a graph in labview, all being controlled and interfaced via a micro-controller. Such applications can be used in astronomy as a proximity sensor to make sure the telescope does not approach certain areas, also to measure liquid level in a tank and as a security system to detect the presents of objects in restricted areas.

In this project we measure distance of objects within 4cm to 5m range and plot the actual position of the object on a graph in labview. The Ultrasonic sensor circuit generates high frequency (40 kHz) sound waves (ultrasound) and evaluates the echo which is received back by the sensor. The ultrasonic transducer circuit measures the time taken for a pulse of sound to travel from the transmitter unit to a particular target and back to the receiver unit as a reflected echo and this time is used to calculate distance. The stepper motor is used to turn the ultrasonic sensor, getting distance readings of objects at each step taken by the stepper motor. The object position is displayed on a graph in labview. The micro-controller is the heart of this system as it is used to interface the ultrasonic transducer, stepper motor, labview and limit switch. See the device in real motion below:

You can download the full project document here