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- Newsgroups: comp.robotics
- Path: sparky!uunet!utcsri!torn!newshub.ccs.yorku.ca!newshub.ariel.yorku.ca!cs911225
- From: cs911225@ariel.yorku.ca (KEN E WILLMOTT)
- Subject: Re: IR remote timing
- Message-ID: <1992Dec22.171631.13996@newshub.ariel.yorku.ca>
- Sender: news@newshub.ariel.yorku.ca (USENET News System)
- Organization: York University, Toronto, Canada
- References: <1992Dec21.165153.1282@newshub.ariel.yorku.ca>
- Date: Tue, 22 Dec 1992 17:16:31 GMT
- Lines: 69
-
- Hi,
-
- Hate me if you like, but I posted erroneous data about infrared
- remotes, and I thought it would be better to repost, so I fixed
- the figures and added info about the continuous key mode.
-
- I found the postings about the Sony infrared remote control
- protocol interesting, but I was alarmed to note that it did
- not seem to mesh with the readings I got from 3 different
- controls in use in my living room. These are an RCA t.v.,
- an Onkyo receiver, and a Jerrold tuner.
-
- Here is what I found (presence of signal = logic 1):
-
- First, there is an AGC stabilization pulse, followed by a short
- break. Then come the mysterious bit patterns (I'll get to them).
-
- Signal Duration Polarity
- ------ -------- ________
-
- AGC pulse 9.15 ms 1
- pause 4.33 ms 0
- 50 3-bit patterns 1125 us (see below)
-
- Each 3-bit pattern consists of three 375 us. long bits.
- The first two are always the same, and convey the binary
- information. The last is always set to 0.
-
- When these bits are laid out end to end, they look like
- the following (actual data from one of my controllers):
-
- 11 01 11 01 10 10 10 11
- 01 01 10 10 11 10 10 10
- 10 11 11 01 11 11 01 01
- 01
-
- There are two interesting features of this stream, neither
- of which I am sure is always true, or merely an artifact
- of the particular button I chose.
-
- 1) The pattern 00 never appears
- 2) The pattern 10 never precedes the pattern 01
-
- Note that this can't be what I believe is called Manchester or
- simple phase encoding, because of the presence of four con-
- secutive ones. My grouping of bits into pairs is only based
- on a gut feeling, and may be a red herring.
-
- When some keys are held down continously, a different type of
- packet is sent. It looks like this:
-
-
- Signal Duration Polarity
- ------ -------- ________
-
- AGC pulse 9.15 ms 1
- pause 2.10 ms 0
- stop pulse 750 us 1
-
- time until
- next packet 38.6 ms 0
-
-
- As I have said before,
- if anybody out there has more information to add to this,
- I would be eternally grateful.
-
- -Ken
-
-