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The Dome

A project log for Interact

Physically interacting with the world can be extremely difficult for some. This project aims to make it a little easier.

mike-turveyMike Turvey 08/24/2020 at 08:120 Comments

One of my original requirements was that the switch be easily triggered by hitting it on the side.  While the existing flat switches do still work if you hit them on the side, it seems like we can do better.  If the switch cap is a dome, then any force hitting it on the side would still result in a downward force.  Here's my first iteration of such a design.

This first attempt was a bit of a failure.  It is basically a hemisphere on top of the existing switch.  There are two main issues here.  First, there are still flat sides, and those aren't great.  The other issue was a bit of a surprise to me.  This design has a lot of infill, making the switch cap much heavier.  As a result, on rare occasions, the switch will stay depressed even when you stop pushing it.  From a usability standpoint, that's a huge problem.  Back to the drawing board.

And here's the redesign:

This fixes both issues with the "hemisphere" design above.  Most of this switch is just a 2mm thick shell, so there's little added weight.  And the design is smoothly curved, but even out to the edges there is a substantial slope, so it's exceptionally easy to depress, even with a completely lateral movement.

I think it's also worth taking a moment to look back at the original goals.  There is no single switch that could ever be the one design that's best for everyone.  For example, the flat switch is a better design for using as a headrest-mounted switch because it's more comfortable to push than the dome.  But the dome is probably better when on a tray or table, as it requires less precision to activate. When identifying the right assistive technology for a given situation, you've got to be fluid with your assumptions and willing to try, fail and try again to find what will work best.  In that vein, this project is not trying to come up with "the perfect switch."  It doesn't exist.  What I hope to accomplish is to put out a set of different designs, for various affordable switches that will hopefully meet a the needs of a wide array of users and be equal or superior to what you can buy right now for a burdensome amount of money.

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