Summary

Its really hard to improve a design that is practical, cheap to make, even beautiful in its simplicity; my remake is just a different approach: I had some extra 10mmx10mm square magnets from another project and I had no proper spring to use on the original key.

These are changes made, not improvements:

1)replaced spring with magnets; moved the magnets pair somewhat closer to the business end so it creates a bit more tension when keying.
2)replaced the knob with a squashed sphere; I don't know how to use Open Cad so I used Tinkercad online.

If you think you want to mount the original key, or this remix, there are two unused holes: one bellow the arm screw and one in the square hole where the cable is making the connections to the key. I am saying again that the original key is really carefully designed and the author deserves all the credit.