#include <Wire.h>

int led = 4; //led pin
int i = 0;
void setup() {
  Serial.begin(115200); 

  //Begin Communication, no need for any address because this is the master
  Wire.begin(); 

  pinMode(led, OUTPUT);
}

void loop(){

   //This is the part where the control requests data from a node
  //Wire.requestFrom("address of node", "amount of bytes to request", true or false to not cut or cut communication)
  
  Wire.requestFrom(1,64); //requesting 64 bytes from node1

  while(Wire.available()){
    int c = Wire.read();

    if(c == 5){
      Serial.println("Button on node1 was pressed");
      
      // blink led 4 times
      for (i = 0; i <= 3; i++) { 
       digitalWrite(led, HIGH);
       delay(200);
       digitalWrite(led, LOW);
       delay(200);
      }
    }
     
    Wire.requestFrom(2,64); //requesting 64 bytes from node2
    
    while(Wire.available()){
      int c = Wire.read();

      if(c == 8){
        Serial.println("Button on node2 was pressed");
        
        // blink 4 times
        for (i = 0; i <= 3; i++) { 
        digitalWrite(led, HIGH);
        delay(200);
        digitalWrite(led, LOW);
        delay(200);
        }
      }
    } 
  }
}