How To Make Line Follower Using Three IR Sensor | Arduino Line Following Car

Line Follower Cars are autonomous cars that follow a given route. We have already learned to make a Line Following Car using 2 IR sensors to follow easy tracks. Today we'll make a Line following car using Arduino and 3 IR sensors, that will precisely follow a black line over a white surface, take sharp 90 degree turns and easily follow high curvature curves.

Before moving ahead, make sure you understand the Working Mechanism of IR Sensor and learn how to make 2 IR Sensor Line Follower Robot. This project is an upgrade of 2 IR Sensor Line Follower Robot. 

Hardware Setup

Components Required:

• Arduino UNO
• Motor Driver L298N
• Car Chassis (Car Frame | 2 x DC gear Motor | 2 x Tires)
• Jumper Cables
• 3 x IR Sensor 

Car Assembly:

The first step is to assemble the car chassis. To learn more about assembly, refer to this article: Assemble Car Chassis. For visual demonstration refer to this video: Assemble Car Chassis.

Circuit Diagram:

Software Setup

Arduino needs to be programmed such that the car follows a black line over a white surface. (Have a black line over a white surface? Watch the video at the end to learn a small trick and customize your code 😏). We have written the code such that it follows the following rules:

Note: Green Dots show the position of the Sensors.

Code

	#define MS 12 // Middle Sensor
	#define LS 13 // Left sensor
	#define RS 11 // Right sensor
	#define LM1 2 // left motor
	#define LM2 3 // left motor
	#define RM1 4 // right motor
	#define RM2 5 // right motor
	void setup()
	{
	Serial.begin(9600);
	pinMode(MS, INPUT);
	pinMode(LS, INPUT);
	pinMode(RS, INPUT);
	pinMode(LM1, OUTPUT);
	pinMode(LM2, OUTPUT);
	pinMode(RM1, OUTPUT);
	pinMode(RM2, OUTPUT);
	}
	void loop()
	{
	if(digitalRead(MS)) // Middle Sensor On Line
	{
	if(!digitalRead(LS) && !digitalRead(RS)) //LS and RS not on line
	{
	Serial.println("move forward");
	digitalWrite(LM1, LOW);
	digitalWrite(LM2, HIGH);
	digitalWrite(RM1, LOW);
	digitalWrite(RM2, HIGH);
	}
	else if(digitalRead(LS) && !digitalRead(RS)) //Sharp Left
	{
	Serial.println("Sharp Left");
	digitalWrite(LM1, LOW);
	digitalWrite(LM2, HIGH);
	digitalWrite(RM1, HIGH);
	digitalWrite(RM2, LOW);
	}
	else if(!digitalRead(LS) && digitalRead(RS)) //Sharp Right
	{
	Serial.println("Sharp Right");
	digitalWrite(LM1, HIGH);
	digitalWrite(LM2, LOW);
	digitalWrite(RM1, LOW);
	digitalWrite(RM2, HIGH);
	}
	else if(digitalRead(LS) && digitalRead(RS))
	{
	digitalWrite(LM1, LOW);
	digitalWrite(LM2, LOW);
	digitalWrite(RM1, LOW);
	digitalWrite(RM2, LOW);
	Serial.println("Stop");
	}
	}
	else
	{
	if(digitalRead(LS) && !digitalRead(RS)) // Turn left
	{
	digitalWrite(LM1, LOW);
	digitalWrite(LM2, HIGH);
	digitalWrite(RM1, LOW);
	digitalWrite(RM2, LOW);
	Serial.println("Left");
	}
	else if(!digitalRead(LS) && digitalRead(RS)) // turn right
	{
	digitalWrite(LM1, LOW);
	digitalWrite(LM2, LOW);
	digitalWrite(RM1, LOW);
	digitalWrite(RM2, HIGH);
	Serial.println("Right");
	}
	else if(!digitalRead(LS) && !digitalRead(RS)) // turn right
	{
	digitalWrite(LM1, LOW);
	digitalWrite(LM2, LOW);
	digitalWrite(RM1, LOW);
	digitalWrite(RM2, LOW);
	}
	}
	delay(5);
	}

view raw How To Make Line Following Car Using 3 IR Sensors And Arduino hosted with ❤ by GitHub

Demo

Now the most exciting part of the project, seeing our car precisely follow a complex track. Refer to the video below to see how well the car follows sharp 90 degree turns and high curvature curves.

Now you can upgrade your Line Following Car easily, and win competitions. In case of any questions, feel free to comment below. Happy Learning :)