Use Android Smartphone as Compass without any App

There are several free Compass apps on Google play, but why cram your phone's memory with one more App when you can do away with just a simple trick.You don't need internet access or GPS connectivity as long as you have Magnetic Sensor on your phone which most smartphones have.
   To begin just dial the USSD code : *#0*# and then tap on Sensor button in the menu that appears.
This will show up the Magnetic sensor interface you can use as a Compass.

Magnetic Sensor functioning as Compass with the blue streak  pointing North

For best results hold your phone parallel to the earth's surface and away from any possible source of Electromagnetic field.