Place it at the start of a boarding scene, just as the card reaches the reader, then follow with a soft bell ding once the passenger is seated and the journey begins.
關於此聲音
This is the short confirmation tone heard when an Adelaide Metro card is tapped on a bus or train reader, lasting just over a second. The crisp electronic chirp feels familiar and satisfying, like a small green light for the journey ahead. It comes from Adelaide's public transport system, where tapping on records the fare before the ride begins.