Iron - Light pen.

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             Light pen

   The principle of operation of a light pen is
The following is expected.   you bring
a device the size of a felt-tip pen to the desired
screen point and photosensitive element
inside your pen ~catches~ the scanning beam
images. Further support program you-
calculates the exact location of a point on
screen.  The light pen diagram is shown in
accompanying figure (see Figure A).

   Convenient for making a light pen
use the body of a felt-tip pen, such
size so that inside it near the entrance
holes could be placed light-
sensitive element. Not a bad result
gives use as such an element
ment, a low-power transistor with sufficient
but with a high gain, for example
measures, KTZ102E, which needs to be removed
pour the upper part of the body. Light pen
connected to the interface with a flexible cable
1.0 - 1.5 m long. Presentation interface
This is a port (with address 63 DEC) input
information to the D0 data bus. It's done
on a chip with three states -
K1SSLP8. A correctly assembled circuit requires
only selecting resistor R3 ( 0.3 - 3.3
mOhm) to select the sensitivity threshold.

   Light pen software support
carried out by the editor "LPЧ8K".───────────────────── ─────────────────────

The article is reprinted from the methodological publication
boots NTK "PLUS","PC INTERFACES SPECTRUM"
Max dialed (65-42-13).

 From the editor: We ourselves do not agree with this device
were also taken for the performance of this scheme
I can't guarantee it. If anyone collected it and, in service
in case of problems with lightpen
Please write to us. How is this done?
It’s written in the EDITORIAL section.