How to get on the road to Smart Machines: The ABC’s of control interface ergonomics

This audio was created using Microsoft Azure Speech Services

Nowadays, most computers use a mouse that have 2 clicking buttons and a middle scroll wheel, unless you are a hardcore gamer. The differentiation of the middle actuator is clearly reflecting its function, which is to enable us to scroll down an internet page or a document.

Similarly, on a machine control interface the choice of pushbuttons and switches are often linked to the ergonomics and the way the operator will be expected to use the machine. One of the simple choices is whether the actuating movement will be a rotation, with a selector switch, or a linear pressure, with the emblematic pushbutton.  So, what are some of the reasons to choose one or the other?

1.  Visibility of status: selector switches

Even with your machine not powered, it is easy to see the status of your control interface with a glance when using a selector switch: the left / right angle of the selector is indeed much easier to identify that the pressed status of a latching pushbutton.

2.  Actuation while wearing gloves: selector switches

When wearing thick gloves, we kind of lose our feelings of touch. It becomes much more difficult to feel the spring of the pushbuttons and each end of its course. Gloves also make it difficult to push the smaller surface of a pushbutton.

On the contrary, even gloves don’t prevent you from grabbing a handle and knowing if you have turned it or not.

Alternatively, there are pushbuttons with large heads dedicated to actuation while wearing gloves, like the following one.

3. Find your function without looking: selector switches or maybe pushbuttons

Imagine that you are looking the movement of you sawing machine and need to press a button to change its speed or position. As you will want to keep your eyes on the saw, it’s quite difficult to find the pushbutton blindly. The selector switch with its large handle is much easier to locate without using your eyes.

4. Precise timing: selector switch with spring return

Another machine requiring an operator action: a manually controlled tank filling. Imagine that you are filling the tank and that you have to release your action to stop the water from flowing. Unless the pushbutton is in your hand, releasing a pressure is not so natural. On the other hand, with a selector switch, you just have to release your hold on the handle and the spring will naturally return the selector to the stopping solution.  We may speak about a one or two seconds difference in the stop order, but that could be a nice difference in productivity if your action is repeated through the day…

5. Speed of actuation

Linear movement is just more natural than a rotation, and just request the movement of a finger rather than a twist of the wrist. Thus, pushbutton is beating selector switches for pure reflex actions or quickly repetitive actions. Actually, a mushroom pushbutton is even better.

If you want to share other reasons to choose between selector switches and pushbuttons, don’t hesitate to share your thoughts in the comments.

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