[net.micro] Homebrew mouse or lightpen

knutson@ut-ngp.ARPA (03/20/84)

Any electronic gurus out there?

I would like to be able to rig up a lightpen or mouse for my Z100.
I know there are some commercial ones but I like to twiddle.  Building
a lightpen doesn't seem that hard.  Just a photo-detector in a casing,
perhaps a lense, and maybe a diode or two (I'm just guessing since
I don't know word one about that kind of stuff).  A mouse would be
a bit tougher but not impossible.  Would the parts for these cost
just as much as the commercial product?