The application of measuring the brightness by using the illuminance sensor mounted on the smartphone.
List of values ​​that can be used as a guide under the measurement value is displayed.
You press the volume key and to pause the measurement, it will continue to display the lux value at the time of pressing.
When the screen toward the display side to the measurement object is not visible, you can measure the brightness and paused at the volume key.

Accuracy of the brightness of the value depends on the smartphone of the sensor.
In addition, the upper limit and lower limit value is also dependent on the smartphone.