[sdiy] Reed Switch and Magnet Keyboard

[phillip m gallo]

Old ASCII / Baudot keyboards often used magnets and read switches.   The
magnets where donut shaped and part of the spring loaded key pedestal.
The reed relay was soldered vertical so upon key depression the magnet
would surround the "reed" switch to about "mid-position".  Later i saw
this technique extend to using Hall Effect sensors instead of "read
relays".

Considering how close individual key's are on a console keyboard
proximity is not the problem.    

regards,
p