Design Heuristic: Visibility of System Status

Many devices that we use, such as laptops, have a “sleep” mode where the device is largely inactive but still on (and can easily be reactivated by the user). It is generally quite helpful for the user to know when their device is in this state and some devices do a good job of displaying this status clearly.

For example, my laptop’s power button blinks slowly when the laptop is “asleep”, as shown in the GIF below:

In contrast, when the laptop is off, the button does not blink and is not backlit; when the laptop is on and active, the button is constantly backlit. Through this mechanism, the laptop is able to effectively convey system status to the user.

An example of a device that does not completely conform to this design principle is the pictured headphones (designed by Plantronics).  The headphones have a set of small lights that can indicate battery life (blue) and whether the headphones have just been turned off (red). However, these lights only stay on for a few seconds before going dim. Normally a user can tell if the headphones are on or off simply from the power switch position (which shows green if the headphones are on). The headphones have a “sleep” mode as well though, which is activated after a period of inactivity. In “sleep” mode, the headphones appear on, but will not actually play sounds until the power switch is toggled. The user has no way of knowing whether the headphones are in “sleep” mode until after putting them on, which can be somewhat frustrating (especially if the user first assumes the headphones might be broken in some way).

One way to fix this would be to incorporate a third type of light — an orange light to indicate that the headphones have switched into “sleep” mode (as shown below). Alternatively, they could incorporate a blinking light as the laptop does. In both cases, it would also be helpful to have another way (besides toggling off and on) to wake up the headphones, perhaps through pushing one of the other buttons. This way users could easily see the headphone’s status and whether they need to wake them up before use.