I got another Hall Effect keyboard in the mail. Not as cool as the first one, but it's older (from 1976) and has much wear on the stems. I took it apart for cleaning. The stems appear to be ABS, and the switch housings are a much harder plastic.
(only picture I took of the keyboard before I took it apart, my "other" keyboard is above for comparison)
(rows of HE sensors)
(all the switches taken apart and lined up. New Fujitsu T580 ultraportable in the background)
(close up of spacebar switch and housing)
(you can clearly see both magnents in this picture
(closeup of IC)
(rows of HE sensors)
These are the "old style" hall effect switches that microswitch / honeywell used from about 1968 to about 1979 or so. The round stems tend to bind a little if you hit them off axis, and this is much more apparent in this keyboard, due to the heavy use it's seen. I took it all apart for cleaning and lubriation. I plan to desolder the PCB and add diodes and a teensy, making it into a usable keyboard. Or maybe I'll use it as a parts unit for future hall effect projects. Heck, even the keycaps are worth it, to use with those "new" hall effect switches we've seen.
