What is a line follower?
By Vedant Dahake
A line follower seems to be a really basic type of robot, but it is widely used in the industry usually for transportation, cleaning, and carrying goods within a facility. Industrial robots are really advanced. We will see about a really basic line follower.
The basic components used in a line follower are IR sensors (at least a pair), a microcontroller, a motor driver, two stepper motors, a castor wheel, and a battery. The IR sensors are arranged in such a way that they form an array of sensors. So, basically, there is a line of black color on some other color (non-black). Let’s consider that the IR sensor gives 0 (is off) when it senses black color and gives 1 (is on) when it senses any other color. When the sensor detects the line, it gives input to the microcontroller which will give output according to the code it is fed. The microcontroller will tell the motor driver to move a particular motor at some speed and the other motor at some other speed in order to move the robot and maintain its course. If the left side of the sensor array detects the line, the microcontroller will tell the motor driver to turn left by decreasing the speed of the left motor and increasing the speed of the right motor and vice versa for a right turn. In layman’s terms, a line follower does some work when it sees a line and some other work when it does not see a line. Thus, the robot will follow the line and will make corrections on its way to the end.
Industrial robots are advanced and use various technologies to make a basic line follower more efficient and faster. A complete readymade array of the same IR sensors is used for better sensing. And concepts like PID (a type of control system) are sometimes applied for better efficiency.
Now let’s see how an IR sensor works. Remember the SONAR concept? An IR sensor works on the same concept. If you don’t remember don’t worry. There are two LEDs in a sensor. One is the transmitter and the other is the receiver. The transparent one is the transmitter and the black one is the receiver. The transmitter emits infrared light in the shape of a cone. This light cannot be seen by the naked eye. When the light hits a non-black surface it reflects back and this reflected light is sensed by the receiver and the sensor ultimately gives an output. The light is not reflected when the surface is black, thus the receiver detects no light and ultimately the sensor gives no output.