Project Documentation

Arduino-Powered Autonomous Obstacle Avoidance Robot with Servo Control

Circuit Documentation

Summary

This circuit is designed to control a robotic system using various components including motors, sensors, and a microcontroller. The system utilizes an Arduino UNO as the main controller, which interfaces with a DC motor driver (L298N) to control the movement of motors and wheels. An ultrasonic sensor (HC-SR04) is used for distance measurement, allowing the robot to navigate its environment. The circuit is powered by a 12V battery and can also be charged using a solar panel through a solar charge controller.

Component List

1. Servomotor SG90

Description: A small servo motor used for precise control of angular position.
Pins: SIG, VCC, GND

2. Motor and Wheels

Description: A set of motors and wheels used for driving the robot.
Pins: vcc, GND

3. L298N DC Motor Driver

Description: A dual H-Bridge motor driver that allows control of the direction and speed of DC motors.
Pins: OUT1, OUT2, 12V, GND, 5V, OUT3, OUT4, ENA, IN1, IN2, IN3, IN4

4. Battery 12V

Description: A rechargeable battery providing power to the circuit.
Pins: +, -

5. Solar Panel

Description: A solar panel used to charge the battery.
Pins: +, -

6. Solar Charge Controller

Description: A device that manages the charging of the battery from the solar panel.
Pins: Solar +, Solar -, Battery +, Battery -

7. Arduino UNO

Description: A microcontroller board based on the ATmega328P, used for programming and controlling the circuit.
Pins: Various digital and analog pins including SDA, SCL, and power pins.

8. Arduino Sensor Shield v5.0

Description: An expansion board for the Arduino that provides additional connections for sensors and modules.
Pins: VCC, GND, various digital pins for sensor connections.

9. HC-SR04 Ultrasonic Sensor

Description: An ultrasonic distance sensor used for measuring distance to obstacles.
Pins: VCC, TRIG, ECHO, GND

10. DC Mini Metal Gear Motor

Description: A small DC motor with metal gears for increased torque.
Pins: IN1, IN2

Wiring Details

Servomotor SG90

SIG connected to Arduino Sensor Shield v5.0 pin 11-G
VCC connected to Arduino Sensor Shield v5.0 pin 11-V
GND connected to Arduino Sensor Shield v5.0 pin 11-S

Motor and Wheels (Instance 1)

vcc connected to L298N DC Motor Driver OUT1
GND connected to L298N DC Motor Driver OUT2

Motor and Wheels (Instance 2)

vcc connected to L298N DC Motor Driver OUT3
GND connected to L298N DC Motor Driver OUT4

L298N DC Motor Driver

12V connected to Battery +
GND connected to Battery -
OUT1 connected to Motor and Wheels (Instance 1) vcc
OUT2 connected to Motor and Wheels (Instance 1) GND
OUT3 connected to Motor and Wheels (Instance 2) vcc
OUT4 connected to Motor and Wheels (Instance 2) GND
ENA connected to Arduino Sensor Shield v5.0 pin 5-G
IN1 connected to Arduino Sensor Shield v5.0 pin 4-G
IN2 connected to Arduino Sensor Shield v5.0 pin 3-G
IN3 connected to Arduino Sensor Shield v5.0 pin 2-G
IN4 connected to Arduino Sensor Shield v5.0 pin 1-G

Battery 12V

+ connected to L298N DC Motor Driver 12V
- connected to L298N DC Motor Driver GND

Solar Panel

+ connected to Solar Charge Controller Solar +
- connected to Solar Charge Controller Solar -

HC-SR04 Ultrasonic Sensor

VCC connected to Arduino Sensor Shield v5.0 pin 5-V
TRIG connected to Arduino Sensor Shield v5.0 pin URF01-A0
ECHO connected to Arduino Sensor Shield v5.0 pin URF01-A1
GND connected to Arduino Sensor Shield v5.0 pin GND-G

Documented Code

#include <AFMotor.h>  
#include <NewPing.h>
#include <Servo.h> 

#define TRIG_PIN A0 
#define ECHO_PIN A1 
#define MAX_DISTANCE 200 
#define MAX_SPEED 190 
#define MAX_SPEED_OFFSET 20

NewPing sonar(TRIG_PIN, ECHO_PIN, MAX_DISTANCE); 

AF_DCMotor motor1(1, MOTOR12_1KHZ); 
AF_DCMotor motor2(2, MOTOR12_1KHZ);
AF_DCMotor motor3(3, MOTOR34_1KHZ);
AF_DCMotor motor4(4, MOTOR34_1KHZ);
Servo myservo;   

boolean goesForward=false;
int distance = 100;
int speedSet = 0;

void setup() {

  myservo.attach(10);  
  myservo.write(115); 
  delay(2000);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
  distance = readPing();
  delay(100);
}

void loop() {
 int distanceR = 0;
 int distanceL =  0;
 delay(40);

 if(distance<=15)
 {
  moveStop();
  delay(100);
  moveBackward();
  delay(300);
  moveStop();
  delay(200);
  distanceR = lookRight();
  delay(200);
  distanceL = lookLeft();
  delay(200);

  if(distanceR>=distanceL)
  {
    turnRight();
    moveStop();
  }else
  {
    turnLeft();
    moveStop();
  }
 }else
 {
  moveForward();
 }
 distance = readPing();
}

int lookRight()
{
    myservo.write(50); 
    delay(500);
    int distance = readPing();
    delay(100);
    myservo.write(115); 
    return distance;
}

int lookLeft()
{
    myservo.write(170); 
    delay(500);
    int distance = readPing();
    delay(100);
    myservo.write(115); 
    return distance;
    delay(100);
}

int readPing() { 
  delay(70);
  int cm = sonar.ping_cm();
  if(cm==0)
  {
    cm = 250;
  }
  return cm;
}

void moveStop() {
  motor1.run(RELEASE); 
  motor2.run(RELEASE);
  motor3.run(RELEASE);
  motor4.run(RELEASE);
} 

void moveForward() {

 if(!goesForward)
  {
    goesForward=true;
    motor1.run(FORWARD);      
    motor2.run(FORWARD);
    motor3.run(FORWARD); 
    motor4.run(FORWARD);     
   for (speedSet = 0; speedSet < MAX_SPEED; speedSet +=2) 
   {
    motor1.setSpeed(speedSet);
    motor2.setSpeed(speedSet);
    motor3.setSpeed(speedSet);
    motor4.setSpeed(speedSet);
    delay(5);
   }
  }
}

void moveBackward() {
    goesForward=false;
    motor1.run(BACKWARD);      
    motor2.run(BACKWARD);
    motor3.run(BACKWARD);
    motor4.run(BACKWARD);  
  for (speedSet = 0; speedSet < MAX_SPEED; speedSet +=2) 
  {
    motor1.setSpeed(speedSet);
    motor2.setSpeed(speedSet);
    motor3.setSpeed(speedSet);
    motor4.setSpeed(speedSet);
    delay(5);
  }
}  

void turnRight() {
  motor1.run(FORWARD);
  motor2.run(FORWARD);
  motor3.run(BACKWARD);
  motor4.run(BACKWARD);     
  delay(500);
  motor1.run(FORWARD);      
  motor2.run(FORWARD);
  motor3.run(FORWARD);
  motor4.run(FORWARD);      
} 

void turnLeft() {
  motor1.run(BACKWARD);     
  motor2.run(BACKWARD);  
  motor3.run(FORWARD);
  motor4.run(FORWARD);   
  delay(500);
  motor1.run(FORWARD);     
  motor2.run(FORWARD);
  motor3.run(FORWARD);