Weird noise from my phone...

Awhile back, I noticed that every so often, my phone would make a weird sound and I couldn't figure out what it was.

My first week's experience using Myki

Victoria (the state in which I live) has an electronic ticketing system called Myki (pronounced "My Key") which revolves around a proximity/RFID card which one can charge online or at dedicated terminals. The general idea is on all supported public transport services, one "touches on" with their card upon entering a ticketed area, and then "touches off" upon leaving said area.. at each point the system should advise if the process was successful and whether you're currently covered for the trip... They're still working out bugs, it seems.