Design of all color line follower sensor with auto calibration ability

The proposed system focusses on designing a Line Follower Sensor for various robotic based applications. Unlike the traditional line follower sensor which uses IR pair as transmitter and photodiodes as receiver and works well only for white line over black surface or vice versa, this paper discusses the designing of sensor array using RGB LED as transmitter and Phototransistor as receiver. This sensor can be used for any colored surface and line as it can switch automatically between Red, Green and Blue color LED depending on surface and line colors making it an all color line follower. Thus, it can be used in places where the robot has to follow a line drawn over changing colored background. The sensor along with the controller is used to form an algorithm that can detect the change in surface color and make a decision to switch to a specific colored LED depending on the color on which it has to navigate. Furthermore, the system is designed for self-adjustment of the threshold value used for the motor control of the robot eliminating the need for manual threshold calculation. The ATMEGA328 controller is used for processing the analog sensor signals and for controlling the motor movement via H-Bridge motor driver. The main purpose of this paper is to design a cost effective and robust sensor that it is capable of sensing the change in its background color as well as line color and switching to a LED color that would differentiate between the surface and the line, self - threshold value adjustment to send motor control signals which in turn would provide proper path to the robot and follow the line and control the locomotion of the robot.