What are the differences between the end-effector control of toes vs fingers? I suspect that your hands have evolved to specialize in fine motor control (examining fruits, eating stuff, picking out lice, etc.) and feet have evolved to provide locomotive stability. I bet there are major differences in its effectiveness beyond just neural training (those with amputated arms can make do).
I saw the "clutch" comment above. Something useful can definitely be done. Perhaps both feet together can improve on what is likely a struggle to be useful at first.
Driving comes to mind, and people do have better motor control than they might believe.
One foot for each axis vs both feet on a platform, or leaning into one with heels on the ground could work, and work differently too.
I do not have time right this minute, but I feel building some hardware might be in my future.
This is the sort of thing one needs to try.
In the 90's I modified the code of a spot welder to give me access to many sets of settings with just the foot pedal as input. That's it. Machine offered nothing else, and adding hardware to it was a no-no.
There were three sets of settings, let's call 'em A, B, C.
A quick tap changed settings.
A longer than "quick" tap placed a weld.
Longer than that delivered welds at the same setting in series, spot, spot, spot, etc.
The machine was a 60Hz machine, and each instruction on it's controller took one cycle. Amazingly, it did have a few program flow on foot pedal state type instructions! I remember one could skip a word, jump and basically pause. That might be all of them. Was enough to implement the flow I put above.
It took the shift after I set the code up for me to do it without really thinking about it.
Why do it?
I had several jobs that required parts be handled more than once, and the worst offender needed three settings.
Programming that old controller was like a simple assembly language. Each instruction word had several fields depending on what it did. And the cool part was getting to write the weld! Close electrodes, open or close pressure valve, modulate weld current, loop back to begin, and the like were there.
Doing the three settings job fit into the number of instruction words it could hold, but not by much!
I think feet can do more than we might think, and at least part of this is a design R&D problem.
The rest, if it makes sense at all, is "human didn't do shit with their feet" problem, agreed.
