Project Documentation

Arduino-Controlled Obstacle-Avoiding Robot with Ultrasonic Sensors and L298N Motor Driver

Circuit Documentation

Summary

This circuit is designed to control a pair of DC gearmotors using an L298N motor driver module, with an Arduino UNO as the central microcontroller. The circuit includes three HC-SR04 ultrasonic sensors for distance measurement, which are interfaced with the Arduino to facilitate obstacle detection and navigation. The motor driver module is powered by a 9V battery and is responsible for driving the motors based on the signals from the Arduino. The Arduino executes a control algorithm, which is programmed to make decisions based on the input from the ultrasonic sensors to navigate through an environment by avoiding obstacles.

Component List

9V Battery

Description: Provides the power supply for the motor driver and indirectly for the motors.
Pins: - (Negative), + (Positive)

Arduino UNO

Description: Acts as the central processing unit of the circuit, interfacing with sensors and controlling the motor driver.
Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0 to A5, SCL, SDA, AREF, D13 to D0

L298N DC Motor Driver

Description: Controls the direction and speed of the DC gearmotors.
Pins: OUT1, OUT2, 12V, GND, 5V, OUT3, OUT4, 5V-ENA-JMP-I, 5V-ENA-JMP-O, +5V-J1, +5V-J2, ENA, IN1, IN2, IN3, IN4, ENB

Gearmotor DC / Motorreductor (2 units)

Description: Provides the mechanical action for the circuit's operation.
Pins: Pin1, Pin2

HC-SR04 Ultrasonic Sensor (3 units)

Description: Measures distances by emitting ultrasonic waves and detecting their reflections.
Pins: VCC, TRIG, ECHO, GND

Comments (3 units)

Description: Placeholder for additional notes or labels within the circuit, not an actual electronic component.

Wiring Details

9V Battery

- connected to GND on the L298N DC motor driver.
+ connected to 12V on the L298N DC motor driver.

Arduino UNO

5V connected to VCC on all HC-SR04 Ultrasonic Sensors and 5V on the L298N DC motor driver.
GND connected to GND on all HC-SR04 Ultrasonic Sensors, GND on the L298N DC motor driver, and - on the 9V Battery.
A2 connected to TRIG on one HC-SR04 Ultrasonic Sensor.
A3 connected to ECHO on another HC-SR04 Ultrasonic Sensor.
A4 connected to TRIG on another HC-SR04 Ultrasonic Sensor.
A5 connected to ECHO on another HC-SR04 Ultrasonic Sensor.
D11 connected to TRIG on one HC-SR04 Ultrasonic Sensor.
D10 connected to ECHO on one HC-SR04 Ultrasonic Sensor.
D9 connected to IN2 on the L298N DC motor driver.
D8 connected to IN1 on the L298N DC motor driver.
D6 connected to ENA on the L298N DC motor driver.
D5 connected to ENB on the L298N DC motor driver.
D4 connected to IN4 on the L298N DC motor driver.
D3 connected to IN3 on the L298N DC motor driver.

L298N DC Motor Driver

OUT1 connected to Pin2 on one Gearmotor DC.
OUT2 connected to Pin1 on the same Gearmotor DC.
OUT3 connected to Pin2 on the other Gearmotor DC.
OUT4 connected to Pin1 on the other Gearmotor DC.

HC-SR04 Ultrasonic Sensors

VCC connected to 5V on the Arduino UNO.
GND connected to GND on the Arduino UNO.
TRIG and ECHO pins connected to various digital pins on the Arduino UNO as specified in the wiring details above.

Documented Code

const int trigPin1 = 11;
const int echoPin1 = 10;
const int trigPin2 = A3;
const int echoPin2 = A4;
const int trigPin3 = A2;
const int echoPin3 = A5;
const int in1 = 9;
const int in2 = 8;
const int in3 = 4;
const int in4 = 3;
const int enA = 5;
const int enB = 6;

#define PWM 200
#define DIS 25

void setup() {
    pinMode(trigPin1, OUTPUT);
    pinMode(echoPin1, INPUT);
    pinMode(trigPin2, OUTPUT);
    pinMode(echoPin2, INPUT);
    pinMode(trigPin3, OUTPUT);
    pinMode(echoPin3, INPUT);
    pinMode(in1, OUTPUT);
    pinMode(in2, OUTPUT);
    pinMode(in3, OUTPUT);
    pinMode(in4, OUTPUT);
    pinMode(enA, OUTPUT);
    pinMode(enB, OUTPUT);
}

void loop() {
    if (FrontSensor() < DIS && RightSensor() < DIS && LeftSensor() < DIS) {
        turn_right();
        delay(3000);
    } else if (FrontSensor() < DIS && RightSensor() < DIS && LeftSensor() > DIS) {
        turn_left();
    } else if (FrontSensor() < DIS && RightSensor() > DIS && LeftSensor() < DIS) {
        turn_right();
    } else if (FrontSensor() < DIS && RightSensor() > DIS && LeftSensor() > DIS) {
        turn_right();
    } else if (FrontSensor() > DIS && RightSensor() > DIS && LeftSensor() < DIS) {
        turn_right();
        delay(180);
        forward();
    } else if (FrontSensor() > DIS && RightSensor() < DIS && LeftSensor() > DIS) {
        turn_left();
        delay(180);
        forward();
    } else {
        forward();
    }
}

void forward() {
    digitalWrite(in1, HIGH);
    digitalWrite(in2, LOW);
    digitalWrite(in3, HIGH);
    digitalWrite(in4, LOW);
    analogWrite(enA, PWM);
    analogWrite(enB, PWM);
}

void turn_left() {
    digitalWrite(in1, HIGH);
    digitalWrite(in2, LOW);
    digitalWrite(in3, LOW);
    digitalWrite(in4, HIGH);
    analogWrite(enA, PWM);
    analogWrite(enB, PWM);
}

void turn_right() {
    digitalWrite(in1, LOW);
    digitalWrite(in2, HIGH);
    digitalWrite(in3, HIGH);
    digitalWrite(in4, LOW);
    analogWrite(enA, PWM);
    analogWrite(enB, PWM);
}

void reverse() {
    digitalWrite(in1, LOW);
    digitalWrite(in2, HIGH);
    digitalWrite(in3, LOW);
    digitalWrite(in4, HIGH);
    analogWrite(enA, PWM);
    analogWrite(enB, PWM);
}

void stop() {
    digitalWrite(in1, LOW);
    digitalWrite(in2, LOW);
    digitalWrite(in3, LOW);
    digitalWrite(in4, LOW);
    analogWrite(enA, LOW);
    analogWrite(enB, LOW);
}

long FrontSensor() {
    long dur;
    digitalWrite(trigPin1, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin1, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin1, LOW);
    dur = pulseIn(echoPin1, HIGH);
    return (dur / 30); // convert the distance to centimeters
}

long RightSensor() {
    long dur;
    digitalWrite(trigPin2, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin2, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin2, LOW);
    dur = pulseIn(echoPin2, HIGH);
    return (dur / 62); // convert the distance to centimeters
}

long LeftSensor() {
    long dur;
    digitalWrite(trigPin3, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin3, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin3, LOW);
    dur = pulseIn(echoPin3, HIGH);
    return (dur / 50); // convert the distance to centimeters
}

This code is responsible for initializing the pins connected to the ultrasonic sensors and motor driver, and contains the main control loop which determines the robot's movement based on sensor readings. The FrontSensor, RightSensor, and LeftSensor functions are used to measure distances from obstacles, and the forward, turn_left, turn_right, reverse, and stop functions control the motors' movements.