Discovering what we need

Posted on 01/09/2019 by IED

Like many areas of human endeavour, design requires prioritising competing demands. Colin Ledsome CEng FIED offers his way

Recently, I heard a radio programme where someone described a new ‘smart’ refrigerator that detected when its door had been left open, and a synthetic voice reminded the user to close it. “If it’s so smart, why doesn’t it close its own door!” was the comment.

It’s true: a simple mechanical timer mechanism, energised by the door being opened, could trigger a spring to close the door after, say, 15 seconds. This would be much cheaper to install than an electronic version, would be more reliable, not need a power supply, and be less intrusive. A simple adjustable timer, using rubber suckers, was part of the mechanism for roller towel machines, to discourage excessive use. If you still have access to one, take a look.

Many of the products that we buy have capabilities that either we do not need or do not use, even though they may have influenced our decision to purchase it in the first place. We buy adjustable shelving, but never change it. We have washing machines with 20 different possible cycles, but only use two. My car came with cruise control, but I don’t use it.

When I was still a practicing designer, I organised design requirements into four categories: essential, ideal, desirable and optional. The ‘essential’ group covered those attributes that must be present for the product to work, both in a functional sense as well as in the interface with its users. ‘Ideal’ traits make a product more than just ‘good enough’.

They would offer something extra that the user would appreciate in addition to making the product suited to its purpose. ‘Desirable’ things were extra features that would be good to have. They may be easy to provide as part of the essential function of the product, or add-on parts which the user might want. ‘Optional’ attributes could be included for a particular customer group, but would not affect the main purpose.

Sometimes the attributes needed come as a surprise. For example, in designing seats for a railway carriage or a passenger aircraft, one unexpected essential is the need to easily replace one if it breaks, or if the space is required for another purpose. This means that the seat must be able to fit into the space available below the luggage racks and above the tops of other seats, to be taken in and out of the cabin without removing other seats.

I still use these categories when planning something new, or in making a complex decision. They help focus on the aspects that are important, and help to avoid distractions. Priorities are clearer, showing where time should be spent or research carried out. They are also useful in a team context for communicating ideas. They help us discover what we really need.


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