Omega Owners Forum
Omega Help Area => Omega Electrical and Audio Help => Topic started by: MaxV6 on 22 December 2011, 17:58:24
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rather than mess up Dave's other thread about speakers any further.
so... my understanding of our current knowledge.
buried in the bowels of the unit , seems to be an IC package responsible for gain/tone control, and input selection, spitting out a signal to amplifiers...
however, to make matters more complicated, i understand it seems to do some sort of operational check to be sure there's actually operation of playback hardware being involved.
(specifically on the Multi CD cart input...)
this being the case, it would seem to me to be the obvious answer ,
1) to determine what logic signal is being fed by the cd cart operation, and replicate it,
2) determine the input level being fed to it from the audio source , and build a simple buffer/attenuator circuit to take a line level input and adjust it to suit the required input.
3) cut the circuit traces feeding the IC the audio signal AND logic signal , and connect either side of those to a switch activated relay, with sufficient switched poles to accomodate all the signal feeds, (rather than running the audio all the way out to a switch, and back again, risking noise induction)
4) fit a line level input socket, with a socket switched earth/shield contact to activate the relay ...
so, when you plug the ipod in using a mini jack stereo lead, the relay flips automatically, and the logic signal and audio signal are switched from the multi CD feed , to the feed form our dummy signal and iPod .
you could alternatively put a manual switch on so you can select between CD cart and iPod, but that means finding somewhere to mount such a thing without looking crap ...
you could , if you wanted to risk additional noise, leave out the relay and do it all by feeding out to the switch and back on all circuits, but i personally wouldn't.
so... who has a unit kicking around in the garage to play with? working CD cart is probably required...
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Been discussed before reed switching the Audio feed on the ribbon cable between CD Changer and HU.
Chris.
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ahh Missed that one....
we chatted about it briefly at the last Wycombe meet, where someone mentioned, in passing, that the system seemed to check there was anything actually playing in the CD cart.....
thus my point about the logic circuit , identifying the signal that tells it there is a valid source, and replicating it.
it probably comes in along that ribbon cable also, so it may become slightly simpler to implement the idea...
got a link? or the result of the discussion?
....
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I did one a while back on a NCDC, used resistor network to lower the MP3 level down a bit then through some capacitors, I/P socket sensor switch through the relays across, like you say down side is CD needs to be on pause from memory.
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Shouldn`t be too hard to disable the CD player completely rather than put it in pause mode
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I see a couple of possibilities...
1) Figure out the (digital) interface to the CD player part and break into it to convince the head unit that it's playing, then switch the CD signal to an external source.
2) Break into the control to the chip that does the input selection in the main part of the head unit and convince it to select CD when the radio would normally be playing, then switch the CD signal to an external source.
1) is nice and easy because it's all external to the head unit, but the interface is undocumented and potentially complex as, I guess, it also conveys track information for the display and controls track and disk selection information into the CD changer.
2) requires bodgery into the depths of the head unit, but the interface to the chip will be both simple and documented so we have some confidence that we could break into it, insert something as an intermediary between head unit and input selector and define our own behaviour entirely.
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To my knowledge theres three possibles been discussed on here in the past. Whats possible or economicl i have no idea though.
Michael Grossers web site give an in depth tv input to cid. There is also a link on interupting the ribbon between cd changer and head units within the double din for audio.
3rd one was raised over a curry reguarding the least used function of the head unit. Which i guess would be the cd player function of the nav slot. This would alllow true integration of other sources with proper mute for phone nav traffic master to over lay those mono inputs.
What i really like re the emulator is the hu thinks its a proper radio signal, so all other sourcres mute it for various amouncements or whatever. Well, as you would expect really, point is it gives a feeling of proper integration. If that can be reproduced for a proper hard wired audio source that would be fantastic. (shame about the interference with all the emulators)
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...and a deathly hush fell about the place. ;D
So where do we go from here? Is any of this realistically possible...?
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...and a deathly hush fell about the place
(http://www.dndservices.co.uk/smiley/Tumbleweed_Emote_V2_0.gif)
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a deathly hush fell, because i was out....... :y
i guess, since it was my big mouth, and the fact that my existing CD changer is knackered, it could take my own one apart and see if i can get sense....
i would like to see one with a working CDC purely because it would help identify and analyse logic and audio signals to have one that will load and play a CD....
but i could possibly make some educated guesses by tracing the circuits a bit .... depending on how much gets hidden in custom packages...
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Ok so Max has the audio... :)
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Watching this one purely to see what you come up with.
As a quick pointer, the audio is the dead easy bit, but you really ought to find a way to disable the spindle motor / laser / sled motor and loading motors, to prevent any unwanted noises generated from searching for Discs, TOC and data etc.
Regretfully, I am unable to assist any further with this one, and I hope you can understand my reasons why not. Firstly, as a repair centre, I cannot encourage the badly performed internal bodges that the subsequent inexperienced watchers will undoubtedly follow as a result of this, and secondly, unless an external plug and play option can be developed (which the stereo will simply never support) then I`m afraid that it is not commercially viable for me to undertake any further research into this.
Best of luck with it though.
(http://www.dndservices.co.uk/smiley/icon_e_ugeek.gif)
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As suspected tbh. No worries Dave. Happy Xmas. ;)
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Of course, my CCR2006 has a cassette, the input from which is ermm... not frequently selected these days. :-\
I lent my cassette deck to a relative about 6 or 7 years ago and have only just noticed it's missing.
In fact the whole cassette mechanism could come out and the slot be turned into a dock for my MP3 player, although if I could be confident that an aftermarket head unit with a USB port would take a substantial music collection on a stick and do a competent job of indexing it, I would just swap it.
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Hmmm, might have a play over Xmas if I get time, seeing as I haven't got a CID yet to play CD70.
My stumbling block will be matching the audio feed in, as thats not an area I excel in (no shit, Sherlock!)
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Hmmm, might have a play over Xmas if I get time, seeing as I haven't got a CID yet to play CD70.
My stumbling block will be matching the audio feed in, as thats not an area I excel in (no shit, Sherlock!)
I don't think there'll be a problem there with Max on the case ;).. It's reverse engineering the signalling interface. Might have to dust off my logic analyser for that...
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Hmmm, might have a play over Xmas if I get time, seeing as I haven't got a CID yet to play CD70.
My stumbling block will be matching the audio feed in, as thats not an area I excel in (no shit, Sherlock!)
I don't think there'll be a problem there with Max on the case ;).. It's reverse engineering the signalling interface. Might have to dust off my logic analyser for that...
I'm not crediting the system with that much intelligence to be honest ::)
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if i was designing a thing like the ncdc/cid combo , i'd have a feed to the control unit with a simple 5v logic high to signal valid source, and then all the complex data to the screen on another "pass thru" feed.... to save the need to have a bunch of decoding stuff to receive the data stream and decide it's indicating a valid source....
a return feed for control input.
and then of course the audio feeds....
i'm currently working on the guessumption that the feed out of the changer is going to be analogue audio, rather than digital, although digital would be a more efficient cost engineering solution.... as the main unit could switch digital inputs to the DA convertors , keeping noise to a minimum, and saving the cost of a second set of DA converters for the SatNav & top CD slot..
i've guessed at this because the cdc mechanism is multi use.... and there are some additional complications to sync'ing up separate digital playback
systems.
it's also borne out by zirk's fun with resistor networks...
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if i was designing a thing like the ncdc/cid combo , i'd have a feed to the control unit with a simple 5v logic high to signal valid source, and then all the complex data to the screen on another "pass thru" feed.... to save the need to have a bunch of decoding stuff to receive the data stream and decide it's indicating a valid source....
a return feed for control input.
and then of course the audio feeds....
i'm currently working on the guessumption that the feed out of the changer is going to be analogue audio, rather than digital, although digital would be a more efficient cost engineering solution.... as the main unit could switch digital inputs to the DA convertors , keeping noise to a minimum, and saving the cost of a second set of DA converters for the SatNav & top CD slot..
i've guessed at this because the cdc mechanism is multi use.... and there are some additional complications to sync'ing up separate digital playback
systems.
it's also borne out by zirk's fun with resistor networks...
It's pretty much bound to be based on the origins of CDC3's and how the single din NCDR11/1500's interfaced to them IMHO.
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in which case, i'm anticipating you would measure about 0.45 V peak on a fullscale sine wave signal (0dBFS )
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in which case, i'm anticipating you would measure about 0.45 V peak on a fullscale sine wave signal (0dBFS )
There's a German article about bodging an audio input into that interface somewhere which indicates that it's analogue audio. Wish I could find it as I think it had a pinout of that connector.
The head unit does also add RDS data to the display, of course, so unlikely that the CDC output is fed straight through, but I see what you're saying. There might be other applications where it is. Interface to the MID display is just a three wire serial line, IIRC, so easy enough to hack if it's similar.
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This one?
http://www.migrosser.de.vu/
Bah, links don't appear to work any more. :'(
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Interface to the MID display is just a three wire serial line, IIRC, so easy enough to hack if it's similar.
Or 2 in the case of CCRT and NCDC models ;)
Are we looking at creating a full blown CDC emulator so the HU can control the gayPod (very, very difficult, and would tie it specifically into crApple players), or just simply trying to feed in an audio signal from any MP3 player (suspect far more trivial, as a guess)
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Uphill kardon input from iPhone 4 3.5 jack has far superior sound quality to the direct iPod control function. But obviously direct control of the iPod function is lost if using the 3.5 mill jack, although the iPhone is dash mounted it is far more distracting to use than the the control knob.
Best thing about it is Tomtom voice mutes the iPod function music, transmitted via Bose. It's great, top quality although voice on one of the tracks is scratchy I guess due to dodgy compression, incoming calls and traffic master mute over that.
Annoyance is selecting the input on harmon karden every time the ignition is turned on, as ignition off re sets to the normal full on iPod control.
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Interface to the MID display is just a three wire serial line, IIRC, so easy enough to hack if it's similar.
Or 2 in the case of CCRT and NCDC models ;)
Are we looking at creating a full blown CDC emulator so the HU can control the gayPod (very, very difficult, and would tie it specifically into crApple players), or just simply trying to feed in an audio signal from any MP3 player (suspect far more trivial, as a guess)
provide a selectable line input, without having to have a cd playing at the same time , not provide control....