How can I calibrate the tilting sensor on Android I have an Android mobile which seems to be of Samsung, or at least a clone thereof. I got it for my wife as a present, so I don't really know which one. Under the battery pack it says "Model: 19502"

when I look through the menus there are absolutely no identifications as to which it is and the settings only allow rather high level stuff, like setting background images, and similar, but nothing system relevant.

When I play games I noticed that the tilt is not correct, so I installed "App Sensor Box" which allows me to test the sensors. It shows a board with a ball on it, and I can see that the ball rolls off when I keep it balanced. Unfortunately this app doesn't allow me to calibrate it, so I wanted to know if such an app exists, or what I can do to calibrate it, because there are not setting to trigger this. The apps I found on Play Store all seem to just read, but don't change it.
It's a tough one to answer, as I'm not sure what version of Android you are running, and you have stated it may be a clone. 

Method 1:

Open "Settings"

Find "Motion" and tap on it

Scroll down the menu and tap on "Sensitivity Setting"

Open "Gyroscope calibration"

Place device on a level surface and tap Calibrate

Method 2:

Download 'G-Sensor' from the Samsung Apps store pre-installed on your device.  Here is a weblink. 

Method 3:

Download  Bubble Level  from the Google Play store, this has a calibration option also.