public static final UUID EIXO_Y                                 = UUID.fromString("00002a47-0000-1000-8000-00805f9b34fb");
 public static final UUID ACELEROMETRO_SERVICE                  = UUID.fromString("00002a45-0000-1000-8000-00805f9b34fb");

gatt.setCharacteristicNotification(gatt.getService(ACELEROMETRO_SERVICE)
                    .getCharacteristic(EIXO_Y, true);