Circuit Documentation

Summary

This circuit is designed to control a robotic system that includes motors, sensors, and a servo. The core of the circuit is an Arduino UNO microcontroller, which interfaces with IR sensors, an ultrasonic sensor, a servo motor, and a DC motor driver that controls four gearmotors. A 4 x AAA battery mount provides power to the system, which is controlled by a rocker switch. The Arduino UNO manages sensor inputs and motor outputs to navigate the robot based on sensor feedback.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• It has 14 digital input/output pins, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header, and a reset button.

4 x AAA Battery Mount

• A battery holder for four AAA batteries
• Provides power to the circuit.

Rocker Switch

• A simple on/off switch
• Controls the power flow from the battery to the circuit.

L298N DC Motor Driver

• A dual H-bridge motor driver
• Allows for the control of two DC motors or one stepper motor.

Gearmotor DC / Motorreductor

• A DC gearmotor
• Provides mechanical motion for the robot.

Servo

• A rotary actuator or linear actuator that allows for precise control of angular or linear position.
• Used for steering or other controlled motion tasks.

IR Sensor

• An infrared sensor capable of detecting obstacles and lines.
• Used for navigation and obstacle avoidance.

HC-SR04 Ultrasonic Sensor

• An ultrasonic ranging module
• Provides non-contact distance measurements.

Wiring Details

Arduino UNO

• 5V and GND are connected to the power rails to provide power to the IR sensors, servo, and ultrasonic sensor.
• Vin is connected to the output of the rocker switch to receive power from the battery mount.
• A0 is connected to the output of one IR sensor.
• A1 is connected to the output of another IR sensor.
• A2 is connected to the ECHO pin of the ultrasonic sensor.
• A3 is connected to the TRIG pin of the ultrasonic sensor.
• A5 is connected to the pulse pin of the servo.
• Digital pins D10, D9, D8, D7, D6, and D5 are connected to the ENA, IN1, IN2, IN3, IN4, and ENB pins of the L298N motor driver, respectively.

4 x AAA Battery Mount

• + is connected to the input of the rocker switch.
• - is connected to the common ground rail.

Rocker Switch

• output is connected to the Vin of the Arduino UNO and 12V of the L298N motor driver.

L298N DC Motor Driver

• 12V and GND are connected to the power supply through the rocker switch.
• 5V is not used in this configuration.
• OUT1 and OUT2 are connected to two gearmotors.
• OUT3 and OUT4 are connected to the other two gearmotors.
• ENA, IN1, IN2, IN3, IN4, and ENB are controlled by the Arduino UNO.

Gearmotors

• Each gearmotor has two pins (Pin1 and Pin2) connected to the corresponding OUT pins of the L298N motor driver.

Servo

• gnd and vcc are connected to the common ground and power rails, respectively.
• pulse is controlled by the Arduino UNO.

IR Sensors

• Both gnd and vcc are connected to the common ground and power rails, respectively.
• The out pins are connected to the Arduino UNO for signal processing.

HC-SR04 Ultrasonic Sensor

• GND and VCC are connected to the common ground and power rails, respectively.
• TRIG and ECHO are controlled by the Arduino UNO.

Documented Code

#define enA 10 // Enable1 L298 Pin enA
#define in1 9  // Motor1 L298 Pin in1
#define in2 8  // Motor1 L298 Pin in2
#define in3 7  // Motor2 L298 Pin in3
#define in4 6  // Motor2 L298 Pin in4
#define enB 5  // Enable2 L298 Pin enB
#define L_S A0 // IR sensor Left
#define R_S A1 // IR sensor Right
#define echo A2    // Echo pin
#define trigger A3 // Trigger pin
#define servo A5   // Servo pin

int Set = 15; // Threshold distance for obstacle avoidance
int distance_L, distance_F, distance_R; // Distances from sensors

void setup() {
  Serial.begin(9600); // Start serial communication at 9600bps
  // Initialize IR sensors as inputs
  pinMode(R_S, INPUT);
  pinMode(L_S, INPUT);
  // Initialize ultrasonic sensor pins
  pinMode(echo, INPUT);
  pinMode(trigger, OUTPUT);
  // Initialize motor driver pins
  pinMode(enA, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(enB, OUTPUT);
  // Set initial motor speed
  analogWrite(enA, 200);
  analogWrite(enB, 200);
  // Initialize servo pin
  pinMode(servo, OUTPUT);
  // Sweep servo to initial positions
  sweepServo();
  // Read initial distance from ultrasonic sensor
  distance_F = Ultrasonic_read();
  delay(500);
}

void loop() {
  // Read distances from sensors
  distance_F = Ultrasonic_read();
  Serial.print("D F="); Serial.println(distance_F);
  // Line follower and obstacle avoiding logic
  if ((digitalRead(R_S) == 0) && (digitalRead(L_S) == 0)) {
    if (distance_F > Set) {
      forword();
    } else {
      Check_side();
    }
  } else if ((digitalRead(R_S) == 1) && (digitalRead(L_S) == 0)) {
    turnRight();
  } else if ((digitalRead(R_S) == 0) && (digitalRead(L_S) == 1)) {
    turnLeft();
  }
  delay(10);
}

// Function to pulse the servo to a given angle
void servoPulse(int pin, int angle) {
  int pwm = (angle * 11) + 500; // Convert angle to microseconds
  digitalWrite(pin, HIGH);
  delayMicroseconds(pwm);
  digitalWrite(pin, LOW);
  delay(50); // Refresh cycle of servo
}

// Function to read distance from ultrasonic sensor
long Ultrasonic_read() {
  digitalWrite(trigger, LOW);
  delayMicroseconds(2);
  digitalWrite(trigger, HIGH);
  delayMicroseconds(10);
  long time = pulseIn(echo, HIGH);
  return time / 29 / 2; // Convert time to distance
}

// Function to compare distances and decide direction
void compareDistance() {
  if (distance_L > distance_R) {
    turnLeft();
    delay(500);
    forword();
    delay(600);
    turnRight();
    delay(500);
    forword();
    delay(600);
    turnRight();
    delay(400);
  } else {
    turnRight();
    delay(500);
    forword();
    delay(600);
    turnLeft();
    delay(500);
    forword();
    delay(600);
    turnLeft();
    delay(400);
  }
}

// Function to check side distances and decide next move
void Check_side() {
  Stop();
  delay(100);
  sweepServo();
  delay(300);
  distance_R = Ultrasonic_read();
  Serial.print("D R="); Serial.println(distance_R);
  delay(100);
  sweepServo();
  delay(500);
  distance_L = Ultrasonic_read();
  Serial.print("D L="); Serial.println(distance_L);
  delay(100);
  sweepServo();
  delay(300);
  compareDistance();
}

// Function to move forward
void forword() {
  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH);
  digitalWrite(in3, HIGH);
  digitalWrite(in4, LOW);
}

// Function to move backward
void backword() {
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);
  digitalWrite(in4, HIGH);
}

// Function to turn right
void turnRight() {
  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH);
  digitalWrite(in3, LOW);
  digitalWrite(in4, HIGH);
}

// Function to turn left
void turnLeft() {
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  digitalWrite(in3, HIGH);
  digitalWrite(in4, LOW);
}

// Function to stop all motors
void Stop() {
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);
  digitalWrite(in