1970's digitizer tablets

From: jpdavis <jpdavis_at_gorge.net>
Date: Tue Jul 15 06:24:00 2003

Peter Turnbull wrote:

>On Jul 14, 11:53, Fred Cisin wrote:
>
>
>
>>What about an under $10 one for a MICROCOMPUTER/PERSONAL COMPUTER?
>>I will lay claim to the dubious honor of inventing that. (even though
>>it was so obvious that MANY people must have done so)
>>In 1983, I wanted a digitizer for blackboards. As a "proof of
>>concept", I attached a one foot long piece of clear plastic (a
>>ruler) to the shaft of a potentiometer. At the other end of it
>>I attached another potentiometer, with another foot long piece
>>of clear plastic attached to the shaft of that one. That made
>>for an upper arm hinged at the edge of the board with a
>>potentiometer, and a forearm hinged at the end of that with a
>>potentiometer at the "elbow".
>>
>>
>
>There was a very similar device around in the early 1980s; I can't
>remember what it was called but it hooked up to one of the machines at
>the college I worked in then, so it must have been for a BBC Micro
>(around 1983) or an Apple ][ or PET (about 1982). Its operational area
>was about an A4 sheet.
>
>
>
Anybody else try depositing carbon ( either pencil lead or other
substances )
on a flat surface and work out the math to get X-Y?
Jim Davis.
Received on Tue Jul 15 2003 - 06:24:00 BST