#include <Wire.h>

const int LED_1_PIN = 5;
const int LED_2_PIN = 6;
const int LED_3_PIN = 7;

void setup() {
  pinMode(LED_1_PIN, OUTPUT);
  pinMode(LED_2_PIN, OUTPUT);
  pinMode(LED_3_PIN, OUTPUT);

  Wire.begin(0x09); // Join I2C bus with address #9
  Wire.onReceive(receiveEvent); // Register event
}

void loop() {
  // Nothing needed in the loop
}

void receiveEvent(int howMany) {
  if (howMany > 0) {
    byte ledStates = Wire.read();

    digitalWrite(LED_1_PIN, ledStates & 0x01 ? HIGH : LOW);
    digitalWrite(LED_2_PIN, ledStates & 0x02 ? HIGH : LOW);
    digitalWrite(LED_3_PIN, ledStates & 0x04 ? HIGH : LOW);
  }
}