Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!elroy.jpl.nasa.gov!zardoz.cpd.com!dhw68k!ofa123!rick From: rick@ofa123.fidonet.org (Rick Ellis) Newsgroups: sci.electronics Subject: Re: TV remote control codes Message-ID: <2468.27B84D61@ofa123.fidonet.org> Date: 12 Feb 91 19:09:21 GMT Organization: Universal Electronics Inc. Lines: 42 On Greg Harp writes: GH> This looks like a good time to jump in with a question I thought of this GH> morning. I came up with the (probably not very original) idea of GH> "digitizing" remote control codes with my computer and playing it back GH> via software control. That's what we do in our remote. GH> Then not only could I add timing features to my audio/video GH> equipment, but I wouldn't have a pile of remotes to deal with. (No, I GH> don't like those universal remotes.) What don't you like about them? GH> Basically, my idea was to make 1-bit samples of the phototransistor's GH> state at up to, say, 50K/sec (I don't know how fast I could push this yet). You'd lose the carrier information since 50k is well below Nyquist. GH> I guess I should ask for some info on the transmission technique. Is the GH> signal just a set of bits that are transmitted one per forty-thousandth of GH> a second, or is another signal modulated at 40kHz, or what? Most remotes modulate a carrier of about 40kHz onto the IR and then turn the whole thing on and off at a much slower rate. Others, mostly older equipment and cable boxes, use no carrier and just send fast single pulses. -- Rick Ellis Internet: rick@ofa123.fidonet.org Compuserve: >internet:rick@ofa123.fidonet.org BBS: 714 939-1041 --------------------------------------------------------------------------