🚀 go-pugleaf

The infrared signals being transmitted by IR controls are a series of 1 and 0's
superimposed over a 40 KHZ carrier. The Radio Shack device (if it is the Sharp
GP1U52X-module I think it is) filters out the carrier and leaves you with the
series of 0 and 1's. If you count the pulses and plots them out you will
see the
differences in signals between various brands of equipment. Sony
re-transmits
the same basic signal a number of times while some other brands do it
just once.

Somewhere on the net there is a description of a device referred to as
the Xanadu
Zapper which when connected to the parallel port on a PC can read in the
signals and
play them back.  There are no source listings in the article allthough
some hints are
given how to program.  On output the point is to again add in the 40 KHz
carrier .

In a German PC magasin of last year there was also an article describing
a similar
device with again only some basic programming hints. I 've built a
device which 
actually combines  the schematics for the Zapper and the German
equivalent and
wrote several drivers. On input I' m sampling (at 80 Khz)  app. 40000
pulses
which in all cases was a sufficent number. I then analyse the signal and
in the end
it requires me to store only about 500 integers (I've have to remember
only the 0-1 
and 1-0 status changes). For Sony devices it must either be 6 times more
of I have to
remember to repeat the signal 6 times on output. On output I reconstruct
the original
signal and do a replay at exactly the same frequency as used on sampling
(with the
carrier added in).

Anyway I've succesfully used the device to reproduce the output for 4
different type 
of remote controls. The disadvantage of the way I've done it is of
course that I have to 
store all the signals.

Allthough I 've taken another approach I do remember that in the German
magasin they
did built an output only device as well and programmed it with pulse
information obtained
from Sony.

Hope this is of help,
Otto


-
*****************************************************************
**  Name : Otto van Kranenburg           Organisation: 
**  Email: kranburg@hlunx3.uto.dec.com   Digital Equipment BV
**                                       P.O.Box 8810
**  Tel (Office): 31 10 453 8213         3009 AV Rotterdam
**  Tel (Home  ): 31 78 510 245          The Netherlands
*****************************************************************