Explaining the mouse redesign process for ergonomic purposes.
As a geek who spend all the time in front of the PC, I always paid attention to the mouse I used, from the ergonomic point of view. starting with a simple Genius to a gaming mouse like Roccat Kone [+]. I’ve tested many of them, and they have in common the tricky habit to break themselves in complicated hours. ( they can smell the fear I guess).
In some of those cases where I had to buy the first one I found, I get a tiny wireless mouse of the Berbatim brand.
It solved the urgent problem, I was able to finish the job, but during the use I felt it very uncomfortable due to its small size.
That’s why I decided to redesign the mouse focusing my efforts in improve the shape according to my hand.
There are some articles that shows the 3 mainly ways to grab a mouse (as you can see here). I ‘ve been paying attention on how I grab the mouse for some days. The ones that I use the most are the palm and claw way. When I’m relaxed, the palm way, when I’m concentrated/hurried, the claw way for fastest movements.
Several mouses on the market makes special shapes for the thumb area rather than the ring and pinky fingers. Actually it’s very common to get those fingers stressed up while grabbing small mouses.
Studying the mouse
After a quick disassembly, I decided to maintain the internal components and piece scheme, To get the same relation between pieces.
Besides the pcb and lens diffuser, I will also put the batteries and receptor holder in similar place.
Modeling internal components
Being a optical mouse, is important to keep the distance from the lens diffuser to the ground plane. The main measurements were on the diffuser and the lower mouse cover and then the pcb holes, scroll placement and so on. The battery contacts are conected by wire so it doesn’t require more atention.
Having those components in the 3d space I start with some simple surfaces. The first try was taking the shape of the Logitech MX 1100. Which I had the opportunity to test and is very comfortable.
Then I made other shapes for exploration. Since It is not good practice to settle for the first thing that comes out.
Finally I choose one of the first models above all, to continue with the internal components and the subdivision to get each cover.
Starting with a unique volume could be tricky to solve the internal fit between pieces but that’s the challenge.
While in injection mold would be more practical to make my logo debossed over the surface, in this case I made it embossed to improve the 3d printing definition.
This exploded view illustrates the same piece scheme and assembly like the original. It also maintain the demoulding of each piece, all of them are simple demoulding except for the lower case which have two slider in the front to lock the upper cover in the assembly.
3D printing the prototype
In order to improve the material flexibility and thin walls definition, I arranged the pieces in a particular way, resulting in much more waste of support material and a considerable increase of printing time.
it was worth it, the printed pieces worked as espected, specially the buttons piece which have to flex without breaking.
The assembly was a little tricky due to the print definition but works anyway.