Tag Archives: ultrasonic distance measurement

Interfacing Ultrasonic Rangefinder with AVR MCUs – AVR Tutorial

Obstacle detecting sensors are one of the most basic type of sensors that electronic hobbyists use. There are several methods to make cheap obstacle sensors. These simple sensors are made using a IR Rx/Tx pair or Normal LED and LDR pair(this design is most basic and is heavily affected by environment lighting conditions). These sensor may be useful for simple requirement but they have following drawbacks :- Can’t say anything about the real distance of obstacle. Give different result for different coloured obstacles. Need calibration (like setting up a variable resistor). To solve these problems we have IR Range Finder Module (like one made by Sharp) but they have small range. Sharp GP2D12 Distance Measurement Sensor has a maximum range of 80cm Sharp GP2D120 Distance Measurement Sensor has a maximum range of 30cm only. To solve all these problem we can use an Ultrasonic Range Finder Module. An Ultrasonic Range Finder Module uses ultrasonic waves (inaudible to humans) to measure distance. These module consist of an Ultrasonic Transmitter (Tx) that emits the ultrasonic wave, the waves after striking any obstacle bounces back and reach the Ultrasonic Receiver (Rx). By measuring the time it take for the whole process to complete and using simple arithmetic we can measure the distance to the obstacle. The Ultrasonic Range Finder Modules has a wide […]