dudek@utai.UUCP (01/28/87)
I have a SONY TV at home with a RM-729 remote control. I was
wondering if anybody knew the protocol the remote uses to talk
to the TV. Are the signals these things send standardized to any
extent? The remote has a clear LED behind a DARK red plastic sheet.
What I'd like to do is build a decoder so that I could control other
appliances around the house using the control from the TV.
Thanks, Greg Dudek
--
Dept. of Computer Science (vision group) University of Toronto
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DELPHI: GDUDEK
Paper mail: 10 King's College Circle, Toronto, Canada tim@ism780c.UUCP (01/31/87)
In article <3090@utai.UUCP> dudek@utai.UUCP (Gregory Dudek) writes: > > I have a SONY TV at home with a RM-729 remote control. I was >wondering if anybody knew the protocol the remote uses to talk >to the TV. Are the signals these things send standardized to any I don't know what protocol Sony uses, but I once wanted to know how these things worked. This worked for me, maybe it will work for you: 1. Get a photodiode from Radio Shack. 2. Hook it up in series with a battery and a resistor. Find the value of the resistor by asking a friendly hardware guy. You are at a university, so there should be a friendly hardware guy available. 3. Borrow an oscilloscope from the hardware guy in step 3. Set it up to measure the voltage across the diode. 4. Point the remote control at the diode and fire away, observing the signal on the 'scope. 5. This worked fine for remote controls that automatically repeat. Howevere, some of mine either did not repeat at all, or sent a seperate code that meant the button was still down. For these, replace the oscilloscope with a logic analyzer. -- Religion: just say "no" Tim Smith USENET: sdcrdcf!ism780c!tim Compuserve: 72257,3706 Delphi or GEnie: mnementh
levy@ttrdc.UUCP (02/01/87)
In article <5367@ism780c.UUCP>, tim@ism780c.UUCP writes: >In article <3090@utai.UUCP> dudek@utai.UUCP (Gregory Dudek) writes: >> I have a SONY TV at home with a RM-729 remote control. I was >>wondering if anybody knew the protocol the remote uses to talk >>to the TV. Are the signals these things send standardized to any >I don't know what protocol Sony uses, but I once wanted to know how >these things worked. This worked for me, maybe it will work for you: > 1. Get a photodiode from Radio Shack.... > 3. Borrow an oscilloscope from the hardware guy in step 3. > Set it up to measure the voltage across the diode. > 4. Point the remote control at the diode and fire away, > observing the signal on the 'scope. Wouldn't it have been simpler to use the 'scope to look at the voltage driving the remote control's LED (presuming the unit could be nondestructively opened up)? >Tim Smith USENET: sdcrdcf!ism780c!tim Compuserve: 72257,3706 -- ------------------------------- Disclaimer: The views contained herein are | dan levy | my own and are not at all those of my em- | an engihacker @ | ployer or the administrator of any computer | at&t computer systems division | upon which I may hack. | skokie, illinois | -------------------------------- Path: ..!{akgua,homxb,ihnp4,ltuxa,mvuxa, allegra,ulysses,vax135}!ttrdc!levy
die@frog.UUCP (02/01/87)
In article <3090@utai.UUCP> dudek@utai.UUCP (Gregory Dudek) writes: > > I have a SONY TV at home with a RM-729 remote control. > What I'd like to do is build a decoder so that I could control other > things with the same remote control. The easiest way to do this is to get a schematic for the TV from a distributor that handles Sony service information and duplicate the remote control circuitry from the TV with appropriate modifications to control whatever you have in mind. This will inevitably mean that you use either one or two of the ICs Sony uses to decode the remote control information. They should be available from the distributor at the usual slightly outraguous prices Sony charges. Duplicating the same functionality in MSI TTL is not easy (and would mean many chips), your only real alternative to their chips is to implement a decoder using the preamplifier/demodulator chip and do your own decoding of the digital data with a dedicated microprocessor. If you choose to use the dedicated micrroprocessor approach you might find using a logic analyzer (borrow one over a weekend from work) to look at the bit patterns emitted by the remote control would make your life much easier as many IR remote controls only send the command information once when you press a button. I believe the data is prefixed with a remote control type code that allows the receiver to reject commands for someone elses TV or VCR. {any remote controls use a bursts of light pulses at between 40 and 70 0 khz to encode a space(or one bit) and no light to encode a mark (or zero bit); the actual data is send as either manchester coding (like a single density floppy) or mfm (like a quad density floppy) at about 1000 bits per second. The data format will consist of a start bit and some fixed preamble bits (the control type code) followed by a command code (which button you pushed) Obviously the easiest way to decode the data is to use the chip Sony uses and figure out what its outputs are. This may be easy to do for one or two outputs, some of the others may be in a more complex format that is not as easy to access. (If you do the logical thing and poke around in the TV with a scope to see what the interface signals are remember - MANY TV's have one side of the power line tied to the chassis and can KILL YOU if you aren't careful to use an isolation transformer). Good luck. -- David I. Emery Charles River Data Systems 983 Concord St., Framingham, MA 01701 (617) 626-1102 uucp: decvax!frog!die
got@psuvm.bitnet.UUCP (02/03/87)
First a good way to tell whether the siganl is being repeated or a special repeat code is being used is to watch the LED that indicates you pressed a button...it's usually connected in some way to the signal that goes to the IR LED. Second, I bought a Motorola IR chipset, and it uses frequency modualtion to encode bits. a low frequency shift to a high frequency shift represents a zero, and visa versa. Such a scheme may make it very hard to use a scope and or a logic analyzer to detect. See if you can get info on the chipset used in your transmitter/receiver from SONY or whoever made the chips. Just call a repair center (not a dealer) and ask someone if they can send you a copy, maybe SONY even sells data sheets, although thats doubtful. Lastly, you could buy the chipset I bought and make your own control center like I am...I will have complete control of every component of my stereo except the EQ from one SMALL transmitter. good luck! ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Sunil Gupta | Bitnet: got@psuecl, got@psuarch, got@psuvma P enn | : sunil@psuvaxg S tate | U niversity | UUCP : ihnp4!psuvax1!psuvaxg!sunil E ngineering | : ihnp4!psuvax1!psuecl.bitnet!got C omputer | L ab | ARPA : got%psuecl.bitnet@wiscvm.arpa
cmcmanis@sun.UUCP (02/03/87)
Last time I checked, Sony and some of the other manufacturers were using
the General Instruments I/R receiver/transmitter chip set. I believe the
GE universal controller uses an 8051 or something driving an LED.
--
--Chuck McManis
uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.ron@brl-sem.UUCP (02/13/87)
In article <3090@utai.UUCP> dudek@utai.UUCP (Gregory Dudek) writes: > > I have a SONY TV at home with a RM-729 remote control. I was >wondering if anybody knew the protocol the remote uses to talk >to the TV. Are the signals these things send standardized to any Steve Ciarcia's did a column in Byte recently on infrared controls. It has a pretty good introduction to the technology. -Ron
berger@clio.UUCP (02/17/87)
My Sony VCR shop manual details the code and timing used. I'll bet the TV service manual carries the information too.
mcintyre@rpics.UUCP (02/19/87)
I just saw the March Byte magazine, and Steve Ciarcia has a project that will solve all the IR controller problems. He describes a programmable IR controller which can analyze any remote's signals and emulate it. A number of different machines can be controlled. -Dave McIntyre