How to Build a Line Follower Robot with Logic Gates (PDF Download)
A line follower robot is a simple and fun project that can teach you the basics of robotics and electronics. A line follower robot is a robot that can follow a black line on a white background, or vice versa, using sensors and logic gates. Logic gates are electronic circuits that perform logical operations, such as AND, OR, NOT, etc. In this article, we will show you how to build a line follower robot with logic gates and provide you with a PDF download of the circuit diagram and code.
What You Need
To build a line follower robot with logic gates, you will need the following components:
A battery holder and batteries
A DC motor and wheels
A chassis or a cardboard base
Two infrared sensors
Four NAND gates
Some jumper wires
How It Works
The basic principle of a line follower robot is to use infrared sensors to detect the contrast between the black line and the white background. The infrared sensors consist of an infrared LED and a photodiode. The infrared LED emits infrared light, which is reflected by the white surface and absorbed by the black surface. The photodiode detects the amount of reflected light and produces a voltage signal. The voltage signal is then fed into the logic gates, which control the direction and speed of the motor.
The logic gates we use are NAND gates, which are universal gates that can perform any logical operation. A NAND gate has two inputs and one output. The output is 0 (low) only when both inputs are 1 (high), otherwise it is 1 (high). We use four NAND gates to create two NOT gates, one AND gate, and one OR gate. The NOT gate inverts the input signal, the AND gate outputs 1 only when both inputs are 1, and the OR gate outputs 1 when either input is 1.
The NOT gates are used to invert the signals from the sensors, so that when the sensor detects a black line, it outputs 1, and when it detects a white background, it outputs 0. The AND gate is used to turn on both LEDs when both sensors detect a black line, indicating that the robot is on track. The OR gate is used to turn on one LED when either sensor detects a black line, indicating that the robot needs to adjust its direction.
The output of the OR gate is also connected to a transistor, which acts as a switch for the motor. When the output is 1, the transistor turns on and allows current to flow through the motor, making it spin. When the output is 0, the transistor turns off and stops the current flow, making the motor stop. The direction of the motor is controlled by another transistor and two diodes. The diodes allow current to flow in only one direction, depending on which sensor detects a black line. For example, if the left sensor detects a black line, the left diode allows current to flow through the left transistor, which turns on and makes the motor spin clockwise. If the right sensor detects a black line, the right diode allows current to flow through the right transistor, which turns on and makes the motor spin counterclockwise.
How to Build It
To build a line follower robot with logic gates, follow these steps:
Connect the battery holder to the breadboard and place it on the chassis or cardboard base.
Connect one end of each resistor to one leg of each LED and connect the other end to a common ground rail on the breadboard.
Connect one leg of each infrared LED to a positive rail on the breadboard and connect the other leg to one leg of each photodiode.
Connect one end of each jumper wire to the other leg of each photodiode and connect the other end to an input of each NAND gate.
Connect another jumper wire from each input of each NAND gate to an output of another NAND gate, creating two NOT gates.
Connect another jumper wire from each output of each NOT gate to an input of another NAND gate, creating a474f39169