#include <Wire.h>
const int endSwitchPin =3;     
int endSwitchState = 0;   
void setup() {
  Serial.begin(9600);
  Wire.begin();
 pinMode(endSwitchPin, INPUT_PULLUP);
}
void loop() {
    Wire.beginTransmission(0x9); 
    Wire.write("On");  
    Wire.endTransmission(); 
    Serial.println("sent");
    delay(1000);
    Wire.beginTransmission(0x9); 
    Wire.write("Off"); 
    Wire.endTransmission(); 
    Serial.println("sent");
    delay(1000);
}