🚀 go-pugleaf

Keith Mancus states
> Odd. I've seen "generic controllers that can be programmed to drive a wide variety of remote-
>controlled devices.

To re-iterate, MOST TV IR-remotes use a 40 Khz carrier.  The generic controllers take advantage
of this.  There are basically two types of 'generic remotes'

I)  The first one is the type that has a IR sensor (a photocell/phototransistor) but into it.
You program the 'generic remote' by aligning your TV/Stereo/CD/VCR remote head-to-head with the
'generic remote'.  You then press one button on the original remote.  The 'generic remote' 
senses the pattern (or modulation) for that particular button and saves it in memory.
Essentially the 'generic remote' is sampling the output from your original remote.  

If you are interested in building/understanding how generic remote controllers like this work,
dig up an old issue of Byte magazine.  I don't have the reference but Steve Ciarcia (now the
editor of Circuit Cellar Ink) had a project where he designs a trainable remote control.  I'm
sure this article will be of help. (Try BYTE circa 1985, 1986).  There's a pretty in depth
discussion of how the IR works.

II)  The second type works on somewhat trial and error.  This is the type of controller you
get on some VCRs that can also control your TV (at least that's what my new VCR controller can
do).  Basically, the remote-control has stored some patterns that are standard for a number of
different TVs (i.e. SONY uses the same pattern[modulation] on all their TVs so you can take 
your remote to a friend's place and play mind games with him as you mysteriously change channels
during the ball game {I've tried this...trust me hours of entertainment as he gets up to smack 
his $1000 TV}.  So basically the controller has to figure out which set of patterns it should
assign to all the buttons.  There's a program button on the 'generic controller'. To train the
remote, the instructions tell you to start pressing buttons randomly.  You will get weird 
behaviour, i.e. pressing 5 will cause the volume to increase and pressing ON will change the
channel. Once you find the button that makes the channel go 'up', you then press the 'program'
button.  The controller can then map which is the correct set of patterns for each button by
looking in its memory for that match.

Hope this helps

-- 
Sylvano

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