Project Documentation

Arduino-Controlled Obstacle-Avoiding Robot with Ultrasonic and IR Sensors

Circuit Documentation

Summary

This circuit is designed to control a pair of DC motors using an L298N motor driver, with inputs from an HC-SR04 ultrasonic sensor and two IR sensors for object detection and line following capabilities. The brain of the circuit is an Arduino UNO microcontroller, which processes sensor inputs and controls the motor driver accordingly. A 4 x AAA battery mount provides the power source, and a rocker switch is included for power control.

Component List

4 x AAA Battery Mount

Description: Provides power to the circuit.
Pins: - (Negative), + (Positive)

HC-SR04 Ultrasonic Sensor

Description: Measures distance to objects using ultrasonic waves.
Pins: VCC, TRIG, ECHO, GND

Arduino UNO

Description: Microcontroller board based on the ATmega328P.
Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0 to A5, SCL, SDA, AREF, D0 to D13

IR Sensor

Description: Detects proximity based on infrared light reflection.
Pins: out, gnd, vcc

L298N DC Motor Driver

Description: Controls the direction and speed of DC motors.
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

Rocker Switch

Description: Allows for manual power control.
Pins: output, input

Hobby Gearmotor with 48:1 Gearbox

Description: Provides mechanical power for movement.
Pins: pin 1, pin 2

Wiring Details

4 x AAA Battery Mount

- connected to GND of the circuit.
+ connected to the input of the rocker switch.

HC-SR04 Ultrasonic Sensor

VCC connected to 5V from the Arduino UNO.
TRIG connected to pin D8 on the Arduino UNO.
ECHO connected to pin D9 on the Arduino UNO.
GND connected to GND of the circuit.

Arduino UNO

5V and GND used to power the IR sensors and the ultrasonic sensor.
Digital pins D2, D4, D5, D6, D8, D9, D10, D11, D12, D13 used for sensor inputs and motor control signals.

IR Sensors

out of one sensor connected to pin D2 on the Arduino UNO.
out of the other sensor connected to pin D4 on the Arduino UNO.
gnd of both sensors connected to GND of the circuit.
vcc of both sensors connected to 5V from the Arduino UNO.

L298N DC Motor Driver

OUT1, OUT2, OUT3, OUT4 connected to the pins of the two Hobby Gearmotors.
12V connected to the output of the rocker switch.
GND connected to GND of the circuit.
5V connected to 5V from the Arduino UNO.
ENA, ENB connected to pins D5, D6 on the Arduino UNO for speed control.
IN1, IN2, IN3, IN4 connected to pins D12, D13, D10, D11 on the Arduino UNO for direction control.

Rocker Switch

input connected to + from the 4 x AAA Battery Mount.
output connected to 12V on the L298N DC Motor Driver.

Hobby Gearmotors

Each motor has two pins connected to OUT1, OUT2, OUT3, OUT4 on the L298N DC Motor Driver.

Documented Code

// Definición pines EnA y EnB para el control de la velocidad
int VelocidadMotor1 = 6; 
int VelocidadMotor2 = 5;

// Definición de los pines de control de giro de los motores In1, In2, In3 e In4
int Motor1A = 13; 
int Motor1B = 12;  
int Motor2C = 11; 
int Motor2D = 10; 

// Sensores infrarrojo - izquierdo y derecho
int infraPin  = 2;    
int infraPin1 = 4;

// Variables para la captura de los valores: 0 - fondo claro y 1 - línea negra
int valorInfra = 0;  
int valorInfra1 = 0;  

// Ultrasonicos
#define PIN_TRIG 9
#define PIN_ECHO 8

long duration, distancia;
// Configuración inicial
void setup() {
  Serial.begin(9600);
  
  delay(1000);
  //configuración del ultrasonico
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  // Establecemos modo de los pines de los sensores infrarrojo
  pinMode(infraPin, INPUT);    
  pinMode(infraPin1, INPUT);

  // Establecemos modo de los pines del control de motores
  pinMode(Motor1A,OUTPUT);
  pinMode(Motor1B,OUTPUT);
  pinMode(Motor2C,OUTPUT);
  pinMode(Motor2D,OUTPUT);
  pinMode(VelocidadMotor1, OUTPUT);
  pinMode(VelocidadMotor2, OUTPUT);

  // Configuramos los dos motores a velocidad 150/255
  analogWrite(VelocidadMotor1, 150); 
  analogWrite(VelocidadMotor2, 180);  

  // Configuramos sentido de giro
  digitalWrite(Motor1A, LOW);
  digitalWrite(Motor1B, LOW);
  digitalWrite(Motor2C, LOW);
  digitalWrite(Motor2D, LOW);
}

// Ejecución contínua
void loop() {
  // Ultrasonico: Primero, generar un pulso corto de 2-5 microsegundos.
  digitalWrite(PIN_TRIG, LOW);
  delayMicroseconds(5);
  digitalWrite(PIN_TRIG, HIGH);
  // Después de ajustar un nivel de señal alto, esperamos unos 10 microsegundos. En este punto el sensor enviará señales con una frecuencia de 40 kHz.
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);
  // Tiempo de retardo de la señal acústica en el sonar.
  duration = pulseIn(PIN_ECHO, HIGH);
  // Ahora es el momento de convertir el tiempo a distancia
  distancia = (duration / 2) / 29.1;
  Serial.print("Distancia al objeto: ");
  Serial.print(distancia);
  Serial.println(" см.");
  
  // Leemos el valor de los infrarrojo: 0 - fondo claro y 1 - línea negra
  valorInfra = digitalRead(infraPin);   
  valorInfra1 = digitalRead(infraPin1);

  Serial.println(valorInfra);
  Serial.println(valorInfra1);
  if (distancia > 10){ //mientras no detecte nada a cierta distancia no se detiene   
      // Cuatro escenarios: De frente      
      if(valorInfra == 0 && valorInfra1 == 0){
        Serial.println("Ninguno en linea");
        
        // Modificamos sentido de giro de los motores
        digitalWrite(Motor1A, HIGH);
        digitalWrite(Motor2D, HIGH);
        delay(20);                      
        digitalWrite(Motor1A, LOW);
        digitalWrite(Motor2D,LOW);
        delay(20);                     
      }
    
      // El robot encuentra línea negra con el infrarrojo derecho y hay que corregir girando a la derecha
      if(valorInfra == 0 && valorInfra1 == 1){  
        Serial.println("Derecho en linea");
        
        // Modificamos sentido de giro de los motores
        digitalWrite(Motor1A, LOW);
        digitalWrite(Motor2D,LOW);
        delay(25);
        digitalWrite(Motor1A, HIGH);
        digitalWrite(Motor2D,LOW);
        delay(20);
      }
    
      // El robot encuentra línea negra con el infrarrojo izquierdo y hay que corregir girando a la izquierda
      if(valorInfra == 1 && valorInfra1 == 0){ 
        Serial.println("Iz