Question 1

How does the magnetometer work?

Accepted Answer

It uses the browser Magnetometer API (on supported Android devices) to read the magnetic field sensor built into your phone. Values are shown in microtesla (µT).

Question 2

Can it really detect metal?

Accepted Answer

Yes, ferromagnetic metals like iron and steel distort Earth's magnetic field. Bring a metal object near your phone and watch the reading spike. It cannot detect non-magnetic metals like aluminum or copper.

Question 3

What is the normal Earth magnetic field?

Accepted Answer

The Earth's magnetic field ranges from 25 to 65 microtesla (µT) depending on your location. A reading far outside this range indicates a nearby magnetic or metal object.

Question 4

Is my sensor data private?

Accepted Answer

Yes. All readings stay in your browser. Nothing is uploaded to any server.