In the line follower robot the robot(here a car which have some wheels in it and which can move)moves along a black line. This project is not a new thing, many toys are there which have implemented this technology or rather build this line follower. This project have the following are some important important section I want to discuss
A line detect section:
In this section an IR transceiver is fitted at the bottom of the car and this IR transceiver( i.e. IR Transmitter and the IR receiver together) is responsible for sensing the black line. The IR transmitter sends the IR ray and the receiver catches the reflected ray. Now the amount of reflection will vary if the IR reflected from white surface or from the black surface(black is the color of the line which is going to be followed by the car).So the IR sensor generates two different voltages on the two situations just described here .Then a comparator used to compare whether black line or white surface.
The decision section generally consists of some microcontroller which is responsible for giving proper signals to the motor etc and the car control circuits so that the car can follow the black line.
When say black line sensed then say comparator output is zero then the microcontroller will decide what to do ,and if white surface then microcontroller will give different signal to the motors and the motor controlling circuit.
What is the real problem with this design??
The real problem is the how to fix the comparator reference voltage. The sensor’s output some times vary with the day light and ambient, I mean you can get different voltage outputs based on which environment you are using the IR receiving sensors. If using light sensors and light /laser transmitter then the problem I is more acute ,but as IR sensors rely on modulation of the IR Transmitters so the problem is less acute but still many trial an trials are required to fix the reference voltage of the comparator.