It is an application developed to control motor speed with Arduino.
There is a panel in the application that shows the engine speed instantly.
Don't forget to allow nearby devices in settings, good luck :)
The signals sent by the buttons to Arduino are as follows:
2500 RPM : 1
5000 RPM : 2
7500 RPM : 3
10000 RPM : 4
12500 RPM : 5
15000 RPM : 6
17500 RPM : 7
20000 RPM : 8
22500 RPM : 9
Stop : 0