Design Heuristic: Visibility of System Status

“The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.”

Hall of fame:

This is a tube amp. It’s a gorgeous piece of equipment, and makes music sound otherworldly. What’s really cool about it, though, is that the visibility of the system status is built into the technology: when a vacuum tube is powered, a filament glows.

Hall of shame:

These are the fire alarms around my house; they’re designed to beep very loudly, so as to resonate the sound throughout a room. And they beep at regular, deliberately-annoying intervals to indicate a low battery. However, because of how the sound reverberates, and because the sound is very infrequent, when one of the fire alarms is low on battery, it’s impossible to tell which one it is.

Fire Alarm 2.0

Fire alarms already have a status light on them. I propose a very simple fix to have this status light indicate not only the fact that the alarm is powered, but also the fact that it is low on power: making this status light blink very quickly in the event that an alarm is low on battery, by rapidly alternating between the two depicted states.