I recently installed a Compass app on my phone (it's a HTC Wildfire S if it matters) and I'm curious as how it works.
Found some answers online that the phone's hardware has a digital compass in it, is that it? or is it just a smart use of other sensors?
Yes, it has a magnetic sensor / digital compass.
Most Android Devices have a Geomagnetic Field Sensor built in. This sensor provides raw field strength data (in μT) for each of the three coordinate axes. You can also use theese values to program things like Metal Detectors.
I programmed one once, if you're interrested in source code let me know.
