On Jul 16, 14:01, Sellam Ismail wrote:
> Ok, my mind is still blown. How does a light-pen drawing program work
> then? (Or is a light-pen drawing program not possible?)
It works by doing what Chuck described (flashing a frame or a line) or as
Megan described (using a target). I've seen it done both ways. I've never
seen a commercial lightpen do what I did, using the low light from "black"
(which isn't quite black) to trigger a sensitive detector -- a detector
that sensitive is just too prone to being swamped by ambient light, I
discovered. It was fine when the pen was pressed against the tube, but
goes haywire when lifted away. I fitted a touch switch to mine to prevent
that, but it still took the amplifier a moment to settle.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Mon Jul 16 2001 - 19:27:32 BST