This application is Magnetic Sensor.
The magnetic field around a phone is measured.

This application can be used for a metal detector etc.

Measurement items are following four.

Intensity: Magnetic field strength in consideration of all of X-axis, Y-axis, and Z-axis ingredient
x-axis: Magnetic field strength of X-axis
y-axis: Magnetic field strength of Y-axis
z-axis: Magnetic field strength of Z-axis

The X axis is horizontal and points to the right, the Y axis is vertical and points up and the Z axis points towards the outside of the front face of the screen.

Unit is micro tesla[uT].

By pushing the "Graph auto zero" button, the measured value of a graph can be moved to zero.