Android

[abdlam]

Hi friends,
please : how the sensors work in the Android phones? when i setup metal detector it works near the metal doors,so how we increace the rang or distance?

[Davor]

Fluxgate sensors in 3 axes.
They react to the Earth magnetic field, and thus provide you with compass function, regardless of the phone orientation. In proximity of ferromagnetic object, and not just any metal, this magnetic field gets distorted and intensified, and that's the way the "metal detector" on Android operates.
You can't do anything else to intensify it.

[lucifer]

Actually the sensors are magnetoresistive, not fluxgate. Their sensitivity is limited can't do anything to increase it.

[aski1]

and if I disassemble it from a phone and I put it in another circuit?

[Davor]

Good luck with that.
It is often much easier and cheaper to simply buy a bluetooth unit with a micro and all the sensors. It all boils down to communication issues. If you can solve communication with the chip you are in, otherwise it is just a completely useless chip.

[lucifer]

and if I disassemble it from a phone and I put it in another circuit?

You better buy a new module and play with it. It will be much easier. For example this one:
https://www.sparkfun.com/products/10530

It has a simple i2c communication protocol and you can also find libraries (for Arduino, etc.)

The problem with sensitivity is not the circuit but the sensor itself. It's able to sense magnetic fields with magnitude close to the Earth's field so you won't get better results.

[bernte_one]

if you use two sensors in one line (same axis) you could make a differential magnetometer

field normal - field strenght is same in both sensors
fe object underground de-forms earth field lines so measure the difference between the two sensors

[bernte_one]