Circuit Lake

Electronic Project and Circuit Collection

Line Follower Vehicle

03/31/2011 Category: AVR, Control, Microcontroller, Project, Robotic

The project aim is to build autonomous car following a line against a luminance contrasting surface. It uses AVR8515 microcontroller to control the drive and steering servos. The car is equipped with an array of sensors (Infrared LED and phototransistor) to detect the path line. Each LED illuminates the floor, and the sensors detect the light reflectance.

AVR line follower robot

To maintain constant speed, a sixth light sensor detects wheel rotation. An LED-sensor pair is mounted facing the wheel. This sensor detects the position of the wheel. By monitoring this sensor over time, it can be determined the period of rotation of the car’s wheels. The PWM signal to the motor is adjusted to maintain the desired speed through a digital feedback algorithm, obtaining data from the wheel.

The autonomous car will automatically stops and enters a data upload state when it looses the line or gets to the end of the track. The speed and steering data, recorded at 10 samples/sec, can be uploaded to a computer and the car’s path can be reconstructed in MATLAB.