Big Red Button - Large Button For Accessibility

Big Red Button - Large Button For Accessibility

What is this thing?

This is a large button I designed for use in a project for children with mobility restrictions. All the large buttons I could find were either too deep/tall/thick, relying on a central core to give stability, or they were shallow and wobbly with only a central switch the button enlarged. Some even used batteries which I did not want to incorporate. The switches simply short the wires hooked up to a 3.5mm audio cable port.

Hello there:

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More Info:

My design incorporates four switches, all wired together, in order to get a consistent and reliable response from a button press no matter which part of the button actuates. It can be pressed on the side, or in the middle, all possible locations will actuate a switch and result in press detection.

Four springs provide the return for the mechanism, giving an even return force all round. These springs are housed in turrets that prevent twist of the button, buckling of the springs, or springs dropping out of position.

The actuation is set up to detect a fairly minor deflection making it easy for someone with mobility issues to use, while avoiding unwanted activation through handling. If required, the actuation point can be adjusted by adding or subtracting from the raised areas on the underside of the button top using simple subtraction or addition cubes inside a slicer program.

The port is a 3.5mm audio jack port. I chose to go with this so the cable is cheap and readily available in any length, with a known, reliable port design. The switches are all combined via wires, then soldered onto two legs of the port. On the device accepting the button input, the exact same setup is used to collect the signal again. For example I used an Arduino Uno on the device; instead of wiring directly into a switch, I wired into a 3.5mm port that leads to this button. The button here uses no power, so needs no batteries.

The clips on the side of the button allow travel but prevent the top from coming loose. To construct the button, once all parts are in place including springs, apply force to the clips to click the top into place. If you need to dismantle it, this can be accomplished without trashing the plastic but pulling the button to the side at a clip location, then pulling it up, you can pop out one clip at a time this way until it's free. Jamming a tool in and levering may break the plastic, but can be done if you're struggling.

I printed this in PETG to prevent warping if left in a warm area which PLA would do, and to give it more robustness.

The STL's are available for you to make this work for your needs, not for republishing.

Parts:

The parts I used were from Amazon UK although I think they are fairly standard. If you source something different you may need to move holes around in your slicer.

Bolts/Screws x8: The bolts/screws through the switches I think were M2, I just tapped the thread into it using the bolt itself. The switch holes are M2.5 I believe, so you could enlarge the holes in the model for that if you had M2.5's laying around. If you feel really fancy you could try to get brass heat inserts in there.

Springs x4: These were from a box of springs https://www.amazon.co.uk/dp/B07WFPPXXX

Limit switches x4: https://www.amazon.co.uk/dp/B08734MSDD

3.5mm Jack Port x1: https://www.amazon.co.uk/dp/B07B2H4L1V