For use in conjunction with https://github.com/ETCLabs/lighthack/tree/master/user_projects/nunchuk - replace the main arduino code with this and open arduino serial terminal to check joystick calibration

joystickTest.ino

#include <Wire.h>
#include "WiiLib.h"

WiiChuck chuck = WiiChuck();

void setup() {
  Serial.begin(9600);
  chuck.begin();
  chuck.update();
  chuck.calibrateJoy();
}

void loop() {
  delay(20);
  chuck.update(); 

  Serial.print(chuck.readJoyX());
    Serial.print("    ");  
  Serial.print(chuck.readJoyY());

    Serial.println();

}