// I2C Master
// Push a button connected to the master controller
// lights an LED connected to the slave

// Andrew Sleigh
// 2018-04-26

#include <Wire.h>

const int buttonPin = 2;     // the number of the pushbutton pin
int buttonState = 1;         // variable for reading the pushbutton status

void setup() {
  Wire.begin();        // join i2c bus (address optional for master)
  Serial.begin(9600);  // start serial for output

  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);
}



void loop() {

  // read the state of the pushbutton value:
  buttonState = digitalRead(buttonPin);
  // Serial.println(buttonState);

  // check if the pushbutton is pressed.
  if (buttonState == 1) {
    
    // turn LED on:
    Wire.beginTransmission(7); // address of slave is 7 
    Wire.write(1);             // sends value byte  
    Wire.endTransmission();     // stop transmitting

    } else {
    // turn LED off:
    Wire.beginTransmission(7); // address of slave is 7 
    Wire.write(0);             // sends value byte  
    Wire.endTransmission();     // stop transmitting
   }
}