Summary

Why I Designed This

My 80 year old father actively uses his computer every day. Everything from spread sheets, to web surfing, to CAD, to playing cards. But the last few years he's been having more and more trouble controlling the mouse. He's been developing age related tremors. Couple that with modern trend of making computer mice smaller and lighter he's finding that he has been more and more accidental button clicks, and shakes unintentionally moving the mouse.

So my solution was to purchase a basic mouse, gut out it's electronics, and remount them in a custom body while using heavier, longer throw switches. I wanted to separate the mouse wheel from the middle button. It should be a tilted design (he really liked an earlier mouse that was like that). I also wanted the switches to have an audible click sound/feel. He also has large hands so something on the big side would fit.

Parts I Used

I purchased a simple no-name 3 button USB mouse from a local computer store. I had salvaged some limit switches from inside an old industrial machine a few years back. They had a good click feel and sound, long travel with decent spring pressure. They also had nice little mounting brackets which will come in handy. I also had some #6 x 3/4" screws designed for use in plastic.

The donor mouse was a TopSync M20 optical 1000DPI. The switches I used were Licon Switch 76-1250 430374.

The Build

First thing I did was dissembled the newly purchased mouse including removing the buttons from the circuit board. I then modeled the parts I was going to use in CAD. I then modeled the mouse body around the parts to get the general shape I wanted. I then modeled the interfaces between the parts followed by designing the buttons.

During the design stage I printed off a couple prototypes to test the circuit board fit and distance from the table (to ensure the laser focused on the surface properly). I also printed an early cover design to check the ergonomics.

Once I was happy with the test prints, I went on and developed each part completely and printed them out.

I had to do plenty of sanding to ensure the buttons and the wheel operated properly. I was happy with the way the buttons turned out, but I would have been a little happier if the wheel was a little looser. No amount of sanding seemed to fully fix this. The wheel still had a few tight spots. But it was way better the when I started.

New wires were soldered to the board to go from where the old push buttons were attached to the board to the new switches. The wires were carefully routed through the body and it was closed up using the #6 screws,

This project was the first time in my 30 year career that I needed to work with free form surfaces. It was quite the learning experience for me. As it is, there are a couple of mistakes in the model due to my inexperience (mainly a triangular section on the front of the cover).

All in all I am quite pleased with the end results. It hasn't stopped all the unintentional clicking, but it drastically reduced them making using the computer a much less frustrating experience for my dad.

Note

The files were all created in imperial units. To convert to metric for slicing, scale everything by 2450%.

I have also included STEP files of all the parts if anyone wants to have a closer look at the design, or hopefully modify it to suit parts available to you. If you do remix anything here, please post them as other people may benefit from them too. Thanks!