VISUAL STATUS INDICATORS
A status light is perhaps the calmest way of conveying a piece of information . It’s also the lowest resolution of all status indicators—at its simplest, a single LED that transmits one bit of information: on or off
Status lights are ideal for communicating low-importance, persistent information . As discussed in the previous chapter, the group messaging system Slack lets you know there are messages to read by adding a blue dot to the app’s icon . This creates an intentionally low-res way of communicating, especially compared with pop-up boxes or the “You’ve got mail!” announcements of years past .
Our daily lives are actually filled with status lights. They carry more information with less distraction than any other status indicator.
Status lights can also convey deeper information through multiple colors and varying levels of brightness . Factor in the ability to turn a status light into a shape or icon, or associate text with it, and you have a powerful visual indicator with relatively little attention load . But lights are not the only visual indicators—seeing when a container is full of liquid (or empty), or when a tomato turns red, can be useful, low-tech visual indicators
Consider the following:
Heat light on a stove
One of the most basic examples of a status light is the heat light on a stove that tells you when a burner is on . A more advanced heat light may signal that the burner is still hot after it’s been turned off, adding useful information without additional complexity
When I was young, my parents got tired of arguing with me about my bedtime To solve this problem, my dad plugged a programmable device called an X10 controller into the wall outlet . He plugged a lamp into it and set it to turn on every evening at 8:30pm . When I hung out with my parents in the living room, I simply scampered off to bed when the light turned on, saving considerable fuss It soon became a part of my life, just as if my parents had told me it was time for bed—the difference being that I couldn’t argue with the light as I could with my parents
Server status light
A status light is an easy way for teams to be aware of how a server is operating without looking at monitoring software In many cases, this is done with rope lights, strung along a wall or ceiling that’s visible to the engineering team: if the build is good and the server is up, the rope is green; if it has an issue that needs attending to, it's yellow; if the server needs immediate attention or has gone down, the rope shows red
An MIT paper from 2005 proposed a light-based faucet (Figure 3-1) that could change color based on water temperature, turning red when the water was hot and turning blue when the water was cold This replaces the sense of touch with a visual display, indicating water temperature without having to check it with a hand, thereby avoiding burns Temperature-sensing glow faucets and shower heads are now available in the online marketplace Amazon com
HeatSink. This LED-powered water faucet attachment indicates visually whether the temperature is hot or cool.*
* Bonanni, Leonardo, Chia-Hsun Lee, and Ted Selker. “Attention-Based Design of Augmented Reality Interfaces . ” Proc. CHI 2005. (https://web.archive.org/ web/2005ii08ig240i/http://web. media. mit. edu/~jackylee/publication/lbr-484- bonanni pd )