Hi all!

I receive many requests regarding how to mesure IR parameters using a PC

Here I post simple programm in quick basic (included in MS-DOS since 5.0
I guess)

The hardware is simple : I use one of the status line (READY) on LPT1
and ground to input signal from remote control receiver. Idle state IR
Receiver produces logical 1 on its output. The only problem I faced is
that status lines register (I/O address - 379) is read differenly
depending upon how do you run your program: under from DOS or Windows.
The port 379 with no signal gives when run in dos - 127 (decimal), when
run under from Windows - 255
So it is necessary to modify it to work in DOS enwiroment (replace 255
with 127)

I ran this programm on 486DX-66 mashine and it was fast enough to wiev
IR signals
from 3 different IR modules I have at home. For faster masine it might
be nesessary to add delay cycle into measuring cycle (between lines 10
and 20).

When you run this programm it first wait for signal to appear on LPT
line and than you press button on remote control unit and catch input
signal.
This method allows to study structure of a signal but does not help with
timing.
To measure time intervals I use SONY remote control unit (it gives
signal in discretes of 0.6 ms) as referense to compare with.

Note that logical 0 in most of IR receivers is presence of signal.


1 DIM a(800)  AS INTEGER

2 rem Waiting for signal to start
5 a(1) = INP(&H379)
8 IF a(1) = 255 THEN GOTO 5

9 rem Store input state to array a(i). You can add dummy cycle within to
make a delay
10 FOR i = 2 TO 800
20 a(i) = INP(&H379)
30 NEXT i

39 rem Printing cycle
40 FOR i = 1 TO 800
50 IF a(i) = 255 THEN PRINT "_";  ELSE PRINT "*";
60 NEXT i
70 PRINT
80 GOTO 5

Regards
Vassili