#include <Wire.h> // This is the library we will be using to allow the board to understand networking instructions.
byte own_address = 2; // This is the address assigned to the board, it will be used to differentiate it from the other boards.
int i = 0;
int servo = 4;
int led = 2;
int angle;
int pwm;

void setup() 
{
  Serial.begin(115200);
  Wire.begin(own_address); // Declare that this is the board called by a certain address.
  Wire.onReceive(receiveEvent); // Instruct what to do when receiving information.
  pinMode(servo, OUTPUT); //
  pinMode(led, HIGH);
  digitalWrite(servo, LOW); //
}

void loop() 
{
  void receiveEvent(int howMany) // What to do when receiving information.
  {
    while (Wire.available()) // While it is being called.
    {
      char c = Wire.read(); // Read the character sent by the main board.
      if(c=='A') //
      {
        digitalWrite(led, HIGH);
        for (angle = 0; angle <= 140; angle += 5)  
        {
          pwm = (angle*11) + 500;      // Convert angle to microseconds
          digitalWrite(servo, HIGH);
          delayMicroseconds(pwm);
          digitalWrite(servo, LOW);
          delay(50);                   // Refresh cycle of servo
        } 
      }
      if(c=='S') 
      {
        digitalWrite(led, LOW);
        for (angle = 140; angle >= 0; angle -= 5)  
        {
          pwm = (angle*11) + 500;      // Convert angle to microseconds
          digitalWrite(servo, HIGH);
          delayMicroseconds(pwm);
          digitalWrite(servo, LOW);
          delay(50);
        }
      }  
    }
  }
}