Thanks guys, that's a lot of advice and ideas!!
I listed the main points.
- Reducing pronation
: I agree, I need to reduce hand pronation. I realized that my hand was far too flat sitting on Bigfoot. But I won't go as far as a vertical mouse position, maybe a 30 to 45° rotation will be enough for me. I've been working with the Logitech Trackman Wheel
for year, and the angle my hand sits on it doesn't hurt and is comfy. I have to stick to the trackball concept as at work I have to control several screens with one device - at some point I had 12 screens controlled with one mouse - otherwise I could have gone for a Hand Shoe mouse
which I think would be a great design for my medical limitations, although I think they are a bit frugal on buttons and there is only a third button for big-handed dudes: only the L size has a third button and I'm M size. Why such a discrimination for smaller hands???
- Ball exposure
: I already dug into the palm rest in order to move the ball away from the keys and give more ball exposure. My experience with the Kensington Expert is that I only use the front half of the ball with my finger tips and up to my second phalanges so I should be OK if the ball is not fully exposed.
- Scrolling/lateral movements
: I haven't received the Slimblade nor the Kensington expert I will sacrifice for this project yet. I think I will end up using the Slimblade. I need to scavenge the ball, housing and ring and put it in place into the mock up to check if the scrolling option will be practical. I need to make sure that the ball is fully operable without the thumb and that I will only use the thumb occasionally, otherwise I will change the thumb rest design so the thumb can reach the ball.
- Palm rest/"fit like a glove" design
: I see what the problem might be, I just like the idea of the hand resting on a palm rest, but you're right, if the ball operation requires a bit of hand movement, having the palm rubbing against the palm rest will be a problem... I will test that as well
- Wrist extension
: I think increasing hand pronation will help with keeping a neutral wrist position. I primarily use my mouse sitting behind my desk... but I might add leg supports for tilting in case I start using it standing up to keep the right wrist angle. But I'm not there yet.
- Finger extension
: Yes the idea is to have the hand the closest to the rest position when reaching the keys. Right now they are very slightly extended (mainly index and little fingers) but I will make some adjustments after I properly fit the ball, housing and ring in the mock up.
- Cherry MX vs microswitches or any other switches
: I'm very new to the mechanical keyboard business so I can't really say what I prefer or not. It was for practical reasons that I initially thought of Cherry MX:
> plate mounted option so I can design a mousecase to clip them on,
> it's much easier to buy a keycap to put on top than design a button for microswitches,
> it's of a smaller size compared to Kurplop's arcade button+microswitch...
... but I was wondering if the actuator travel length of a Cherry MX could be too much (i.e 4mm) for a mouse button compared to a microswitch (approx. 1.5mm) and if the Cherry ML (i.e. 3mm) might be a better option (1mm less but has no plate-mounted option...).