WiD.ino

//include libraries
#include <SoftwareSerial.h>

SoftwareSerial esp8266(3, 2); //RX pin = 3, TX pin = 2

//definition of variables
#define DEBUG true //show messages between ESP8266 and Arduino in serial port
int state = 5; //define initial state of the robot (5 = stand-by)
//define motor pins
const int motor1Pin1 = 5;
const int motor1Pin2 = 6;
const int motor2Pin1 = 9;
const int motor2Pin2 = 10;
//led blink
int sensepin = 0;
int ledpin = 12;
//define motor speed
int motorSpeed = 150; //motor speed (PWM)

//*****
//SETUP
//*****
void setup()
{
  //set pin modes
  pinMode(motor1Pin1, OUTPUT);
  pinMode(motor1Pin2, OUTPUT);
  pinMode(motor2Pin1, OUTPUT);
  pinMode(motor2Pin2, OUTPUT);
  
  //start communication
  Serial.begin(115200);
  esp8266.begin(115200);
  
  sendData("AT+RST\r\n", 2000, DEBUG); //reset module
  sendData("AT+CWMODE=1\r\n", 1000, DEBUG); //set station mode
  sendData("AT+CWJAP=\"ghost\",\"sam12346\"\r\n", 2000, DEBUG); //connect wi-fi network (replace XXXXX by your Wi-Fi router SSID and YYYYY by its password
  delay(5000); //wait for connection

  sendData("AT+CIFSR\r\n", 1000, DEBUG); //show IP address
  sendData("AT+CIPMUX=1\r\n", 1000, DEBUG); //allow multiple connections
  sendData("AT+CIPSERVER=1,80\r\n", 1000, DEBUG); // start web server on port 80
  //led blink
  // put your setup code here, to run once:
  analogReference(DEFAULT); //not necessary

  //   Serial.begin(9600);
  pinMode(ledpin, OUTPUT);
}


//*********
//MAIN LOOP
//*********
void loop()
{
   
  if (esp8266.available())  //verify incoming data
  {
    if (esp8266.find("+IPD,")) //if there is a message
    {
      String msg;
      esp8266.find("?"); //look for the message
      msg = esp8266.readStringUntil(' '); //read whole message
      String command = msg.substring(0, 3); //first 3 characters = command
      Serial.println(command);
           
      //move forward
      if(command == "cm1") {
          state = 1;
      }

      //move backward
      if(command == "cm2") {
          state = 2;
      }

      //turn right
      if(command == "cm3") {
          state = 3;
       }
       
       //turn left
       if(command == "cm4") {
          state = 4;
       }

       //do nothing       
       if(command == "cm5") {
          state = 5;
       }

    }
  }
  
  //STATE 1: move forward
  if (state == 1) {
    analogWrite(motor1Pin1, motorSpeed);
    digitalWrite(motor1Pin2, LOW);
    analogWrite(motor2Pin1, motorSpeed);
    digitalWrite(motor2Pin2, LOW);
  }
  //STATE 2: move backward
  if (state == 2) {
    digitalWrite(motor1Pin1, LOW);
    analogWrite(motor1Pin2, motorSpeed);
    digitalWrite(motor2Pin1, LOW);
    analogWrite(motor2Pin2, motorSpeed);  }
  //STATE 3: move right
  if (state == 3) {
    analogWrite(motor1Pin1, motorSpeed);
    digitalWrite(motor1Pin2, LOW);
    digitalWrite(motor2Pin1, LOW);
    analogWrite(motor2Pin2, motorSpeed);
  }
  //STATE 4: move left
  if (state == 4) {
    digitalWrite(motor1Pin1, LOW);
    analogWrite(motor1Pin2, motorSpeed);
    analogWrite(motor2Pin1, motorSpeed);
    digitalWrite(motor2Pin2, LOW);
  }
  //STATE 5: do nothing
  if (state == 5) {
    digitalWrite(motor1Pin1, LOW);
    digitalWrite(motor1Pin2, LOW);
    digitalWrite(motor2Pin1, LOW);
    digitalWrite(motor2Pin2, LOW);
  }
   int value = analogRead(sensepin);
  value = constrain(value, 20, 250);
 
  int ledlevel = map(value, 50, 250, 255, 0);
  analogWrite(ledpin, ledlevel);
}

//*******************
//Auxiliary functions
//*******************
String sendData(String command, const int timeout, boolean debug)
{
  String response = "";
  esp8266.print(command);
  long int time = millis();
  while ( (time + timeout) > millis())
  {
    while (esp8266.available())
    {
      char c = esp8266.read();
      response += c;
    }
  }
  if (debug)
  {
    Serial.print(response);
  }
  return response;
  
}