Dejan Nedelkovski from How To Mechatronics has a very nice tutorial about making an ultrasonic radar using Arduino and Processing platforms. The project requires an HC-SR04 ranging sensor module mounted on a servo motor to scan the surrounding. The Arduino board control the scan position, as well as receives the ranging sensor output. The received echo data is post-processed on a computer using a Processing-based application and the radar signature is displayed on the computer screen.
A servo motor is a special geared DC motor equipped with an electronic circuit for controlling the direction of rotation, as well as the position, of the motor shaft. Because servo motors allows precise angular positioning of their output shaft, they are used extensively in robotics and radio-controlled cars, airplanes, and boats to control the motion of their various parts. In this lab session, we will first explore what a servo motor consists of and how it works and then illustrate how to interface it with a PIC microcontroller.
This tutorial describes how to control multiple servos with an Arduino module interfaced to a PC through serial port. The application program on the PC is written in Python script that gives control commands to the Arduino module. The Arduino module receives the commands through its serial input and then moves each servo to its commanded position.
The hardware part consists of an Arduino module, four JR Sport ST47 standard servos, and a breadboard to prototype the circuit.