Almost every Samsung smartphone has a secret service menu integrated. In this menu you can test various functions of the integrated hardware for function. This menu is usually used by repair services and service workshops, as it provides a good first insight into whether a hardware component is defective.
However, the title is "Secret" for a reason. Because the menu it cannot be accessed via the Android interface, but only via a special code. This is what we would like to explain to you here:
Open the Service Menu on the Samsung Galaxy S9 or S9 Plus
First open the phone app from the home screen and then switch to the keypad (number pad)
When you have entered the last hash, the service menu will also appear on your display.
This looks like this: Behind each of the fields there are tests that check the hardware of your S9 or S9 Plus. In any case, we recommend that you take a look at "Sensor". In this submenu you will find all your sensor data.
Magnetic sensor, light sensor, proximity sensor, barometer and many more. Take a look around, there's a lot to discover ;-)