Are we done yet?
Design Principle: Redundant cues
Redundant cues are necessary because some people cannot make the connection between certain cues to the signals they are meant to be linked to.
My example of a successful physical artifact that accomplishes the redundant cues is the crossing signal, specifically in California (not implemented in all of Harvard Square). The ones where I live combine the visual cue of a green walking person to indicate “go” and a red hand or person standing still to indicate “stop” for pedestrians with an audio cue for those who cannot see the visual cues. This is extremely useful as about 20 million Americans have vision loss and thus are a large enough group to consider designing for.
This example lacks redundant cues. It is a charger for rechargeable batteries (used in older cameras, toys, etc.) and the light at the very bottom of the charger is red when the batteries are not fully charged but green when they are. This could be a problem for those who are color-blind as they will have a hard time telling when the batteries are charged.
My idea on how to redesign this product is to use both color cues and an alternative visual cue. It is a relatively common cue that we can indicate how full something is based on how many bars are filled in a column. The light indicator should have four sections: each one indicating the percentage in which the batteries are charged (25%, 50%, 75%, 100%). As each bar fills up, it not only provides a visual cue for how much the batteries are charged but it also provides a color cue as well. Each range will be associated with a color too (red, orange, yellow, green), with the traditional colors of green being “good” or “full” and red being “empty”. NOTE: The photo shown has 4 separate battery indicators for the sake of demonstrating what each quartile will look like, but the final design should only have one indicator that runs through all four options.