Jump to content
LegacyGT.com

iPod Direct-connection successful! (but VERY difficult)


centerpunch

Recommended Posts

[quote name='John M']Do you have any info on what the HVAC section shares with the radio? Is it just the faceplate, do they share a wiring harness, etc?[/quote] Oops, a bit of brain fade. Actually, the giant PC board is attached to the plastic front panel, so when you remove the plastic front panel, the PC board comes with it, uncovering a full-size metal plate with 2 small connectors on the front of the assembly. But again, I don't see any possible way to replace the radio in that assembly......
Link to comment
Share on other sites

  • Replies 286
  • Created
  • Last Reply
Hey, great job!! However, your timing really sucks -- I had my radio out this weekend and was staring at that ribbon cable, thinking out loud "if I only knew which conductors to tap into". So I punted and just finished installing an RF modulator last night, only to see your post today!! The RF mod sounds decent, but not as good as a direct in. So maybe I will try this mod next. I'll have a real Frankenstein radio by the time I am done. I was thinking about separating the three conductors from the ribbon cable and breaking them in the middle. Then use a multi-pole switch (or perhaps relays) to switch the radio input from aux-in to CD. There's certainly enough empty space inside the radio case to put some relays. How does the ribbon cable connect to the radio's circuit board?? Does the ribbon slide into the connector and get clamped down, or is the connector permanently attached to the cable and just slides onto pins on the board?? If possible, I'd like to get some extra ribbon cable and connectors. Then I can rig everything up on the work bench into one little module, and plug it inline with the existing cable (ie, no longer cutting/splitting the original cable). Actually, some enterprising person could make these as kits and sell them. Craig
Link to comment
Share on other sites

Well, based on the head spinning I'm getting trying to follow the direct connection methods, there's got to be a market for pre-made "kits". I, for one, would certainly pay a premium to minimize the installation hassles! Kudos to centerpunch and Craig for being pioneers. Ken
Link to comment
Share on other sites

[quote name='c_hunter'] I was thinking about separating the three conductors from the ribbon cable and breaking them in the middle. Then use a multi-pole switch (or perhaps relays) to switch the radio input from aux-in to CD. There's certainly enough empty space inside the radio case to put some relays. How does the ribbon cable connect to the radio's circuit board?? Does the ribbon slide into the connector and get clamped down, or is the connector permanently attached to the cable and just slides onto pins on the board?? If possible, I'd like to get some extra ribbon cable and connectors. Then I can rig everything up on the work bench into one little module, and plug it inline with the existing cable (ie, no longer cutting/splitting the original cable). Actually, some enterprising person could make these as kits and sell them. Craig[/quote] Yes, that sounds like it would work, very good idea. You could probably even wire it all to a 3.5 mm headphone jack for the iPod, and wire it so it would automatically disconnect the CD player audio when you plugged something into the jack (just like the way plugging headphones into a radio disconnects the speakers).
Link to comment
Share on other sites

[quote name='c_hunter']I was thinking about separating the three conductors from the ribbon cable and breaking them in the middle. Then use a multi-pole switch (or perhaps relays) to switch the radio input from aux-in to CD. There's certainly enough empty space inside the radio case to put some relays. How does the ribbon cable connect to the radio's circuit board?? Does the ribbon slide into the connector and get clamped down, or is the connector permanently attached to the cable and just slides onto pins on the board?? Craig[/quote] The ribbon cable simply presses into the connector on the lower (radio) PC board. (The connector is soldered to the pc board.)
Link to comment
Share on other sites

[quote name='centerpunch']Yes, that sounds like it would work, very good idea. You could probably even wire it all to a 3.5 mm headphone jack for the iPod, and wire it so it would automatically disconnect the CD player audio when you plugged something into the jack (just like the way plugging headphones into a radio disconnects the speakers).[/quote] I believe all you need to do is sense voltage across the aux-ins and then have that trigger a relay to switch over. The RF mod I bought does that -- as soon as the iPod starts playing it switches over. After 20 seconds of silence, it switches back. I'm an ME, but I imagine an EE could design this capability quite easily, right down to a suitable capacitor for the 20 second delay! Craig
Link to comment
Share on other sites

[quote name='c_hunter']Actually, some enterprising person could make these as kits and sell them. Craig[/quote] Yeah I was thinking about it.. socketed with automatic switching. However I'd actually have to get some demo parts and put together a business plan, and hopefully people would be interested in that kind of price point (which will probably not be too cheap, especially if I need to make small/sample orders to get the right parts). But this would have an install time of a few minutes with a removed radio, and not make your void warranty obvious :) Just hacking some connectors in is probably going to be a lot cheaper for those who can do it.
Link to comment
Share on other sites

[quote name='centerpunch']The ribbon cable simply presses into the connector on the lower (radio) PC board. (The connector is soldered to the pc board.)[/quote] So the end of the ribbon cable has some sort of contact for each conductor? If these are like the cables used in laptops, as someone else posted, they probably have a coating type of contact. Also, what is the contruction of the wire inside the ribbon? Stranded or solid/foil? Is it relatively robust (I imagine so if you soldered it up). thanks, Craig
Link to comment
Share on other sites

[quote name='c_hunter'] So the end of the ribbon cable has some sort of contact for each conductor? If these are like the cables used in laptops, as someone else posted, they probably have a coating type of contact. Also, what is the contruction of the wire inside the ribbon? Stranded or solid/foil? Is it relatively robust (I imagine so if you soldered it up). thanks, Craig[/quote] The wire is solid foil. I didn't try to solder to it, but I think you could, if you were skilled and careful. I actually found a small 4-conductor SMD connector, inserted the 3 conductor cable into that, and then soldered small wires on the small smd tabs on the connector
Link to comment
Share on other sites

[quote name='c_hunter'][quote name='centerpunch']Yes, that sounds like it would work, very good idea. You could probably even wire it all to a 3.5 mm headphone jack for the iPod, and wire it so it would automatically disconnect the CD player audio when you plugged something into the jack (just like the way plugging headphones into a radio disconnects the speakers).[/quote] I believe all you need to do is sense voltage across the aux-ins and then have that trigger a relay to switch over. The RF mod I bought does that -- as soon as the iPod starts playing it switches over. After 20 seconds of silence, it switches back. I'm an ME, but I imagine an EE could design this capability quite easily, right down to a suitable capacitor for the 20 second delay! Craig[/quote] Headphone jacks use a simple built-in mechanical switch that switches off the speakers when the jack is physically inserted.
Link to comment
Share on other sites

Wow! You guys are amazing! This is definitely way beyond anything I'd feel comfortable with. Perhaps if there was a kit and DETAILED instructions with LOTS of pictures to help guide me. Until then... Thanks for digging in and risking your radio centerpunch. Even though I understood about 20% of what was said (blah blah blah radio blah blah blah CD player blah blah blah, reminds of that Gary Larsen comic strip Farside...) Keep us updated! -Ian
Link to comment
Share on other sites

[quote name='centerpunch'][quote name='John M']Do you have any info on what the HVAC section shares with the radio? Is it just the faceplate, do they share a wiring harness, etc?[/quote] Oops, a bit of brain fade. Actually, the giant PC board is attached to the plastic front panel, so when you remove the plastic front panel, the PC board comes with it, uncovering a full-size metal plate with 2 small connectors on the front of the assembly. But again, I don't see any possible way to replace the radio in that assembly......[/quote] So you don't think I'll be able to physically (and permanantly) remove the radio's electronics without harming the HAVC section? I'm actually not interested in a DIN replacement. I plan to flush a touchscreen display into the dash and build a carputer. Of course, I can't do that if the HVAC is completely integrated with the radio's circuitry.
Link to comment
Share on other sites

I can tell you that the connectors for the climate control plug into jacks that are soldered to the same circuit board used by the radio. So from that standpoint, I think the radio and HVAC are integrated. You can remove the CD changer and leave the guts of the radio there, even if you don't use the radio. That would free up some space. Craig
Link to comment
Share on other sites

[quote name='sigmeda']2 quick questions, 1) I assume the mixing resistors/cap circuit is one setup per signal line? 2) Does adding 2k ohms of resistance to the original CD signal change anything? Gives me some ideas for hacking around in my current Maxima... --sigmeda[/quote] Yes, you need to do 2 of the little circuits, one for left, one for right. (Incidentally, I didn't keep track of which was which, so I used the intro to Pinball Wizard--which has the intro Bminor riff on the right channel--to confirm that I had it straight!) Yes, the resistors cut the audio down 6 db, but the resistors are necessary to isolate the devices from each other. If you used a switch instead of the circuit you wouldn't need the resistors. (Probably--- I haven't tried!)
Link to comment
Share on other sites

[quote name='centerpunch'][quote name='sigmeda']2 quick questions, 1) I assume the mixing resistors/cap circuit is one setup per signal line? 2) Does adding 2k ohms of resistance to the original CD signal change anything? Gives me some ideas for hacking around in my current Maxima... --sigmeda[/quote] Yes, you need to do 2 of the little circuits, one for left, one for right. (Incidentally, I didn't keep track of which was which, so I used the intro to Pinball Wizard--which has the intro Bminor riff on the right channel--to confirm that I had it straight!) Yes, the resistors cut the audio down 6 db, but the resistors are necessary to isolate the devices from each other. If you used a switch instead of the circuit you wouldn't need the resistors. (Probably--- I haven't tried!)[/quote] It won't be safe to hook it up with no resistors at all, even with a switch. A small value resistor will have a negligible impact on playback level, but provide a good deal of safety. i.e. at least 100 ohms. A switch may also allow DC offsets during the switch, so a capacitor should also be used.
Link to comment
Share on other sites

Can you guys educate me as to the purpose/function of the RC circuit? (I'm a rocket scientist, so lay it on, I love details). Is there any way to minimize the impact of the RC circuit on the signal level? The stock radio has a loudness function that reduces bass at higher volumes. I have found that I can take the volume up to about 17 without losing too much oomph. Beyond 20 it gets pretty flat and unappealing. So I think we are in a delicate situation where we don't want to crank the volume higher to compensate for power losses in the RC circuit -- it just won't sound as good. I could compensate on the aux in, since I use the Belkin auto-kit and it allows me to boost the line level a smidge without any noticeable degradation of sound quality. but I would hate to lower the line level coming out of the CD, since there's no way to compensate for that. If I could find a nice looking push button switch (something slightly recessed or flush fitting would look great), it could be mounted to the upper left of the volume knob where there is a blank spot on the radio panel (opposite the hazard blinker button). It would take some drilling and grinding to clear out the metal backer plate, but that is peanuts compared to the full mod! That way you could hit CD (with any CD playing) and then hit the switch to enable the aux-in. Craig
Link to comment
Share on other sites

[quote name='c_hunter']Can you guys educate me as to the purpose/function of the RC circuit? (I'm a rocket scientist, so lay it on, I love details). Is there any way to minimize the impact of the RC circuit on the signal level? If I could find a nice looking push button switch Craig[/quote] Impedance matching and DC isolation. If the driver from the cd player has a low impedance output, and also the ipod, driving the ipod signal into the cd player's output circuitry could damage both (and also cause cancellation of the output leading to no audio or distortion). The circuit basically limits the amount of current that can be drawn/sent to protect both units and allow for mixing. Without knowing specifics about the output voltage/current/impedance on the cd player it's hard to pick good values for this circuit. However 1kohm does seem a bit high, I think you could cut this down quite a bit so you get a lot less that 6dB loss. (disclaimer: don't blame me if this smokes something) Also I think an autoswitcher would be much more effective (and negligible loss), it would get rid of the above problem as well.
Link to comment
Share on other sites

Thanks for the explanation. I am very tempted to use a switch or relay (maybe with auto sense) to select one or the other input rather than mix them together (though it is more complicated) and you can just have any CD (or all CDs) play rather than worrying about a blank. Whatever the case, I think we need to get the loss down a lot lower than 6dB, just because the stock radio does not have a lot of guts to begin with. So any info which improves that would help. I'm trying to get samples of the cables and connectors, and then see how everything can be assembled into a compact circuit that is plug and play (after you take everything apart of course!). I'm really just interested in getting it to work for my car, but I think someone could turn this into a group buy or even a small side business. So if anyone is interested in picking up the ball, let me know and I will gladly participate in some of the ground work. We can easily get some custom circuit boards made for not too much money -- there are companies that will take your design and etch out the raw boards and even solder components on based on a design submission. We use them ocassionally for prototypes and one-offs. The cost is actually not that bad, since they are set up for small jobs to begin with. If we had a few dozen or a hundred people interested, I am convinced it would be reasonable. Craig
Link to comment
Share on other sites

[quote name='c_hunter']So if anyone is interested in picking up the ball, let me know and I will gladly participate in some of the ground work. We can easily get some custom circuit boards made for not too much money -- there are companies that will take your design and etch out the raw boards and even solder components on based on a design submission. We use them ocassionally for prototypes and one-offs. The cost is actually not that bad, since they are set up for small jobs to begin with. If we had a few dozen or a hundred people interested, I am convinced it would be reasonable. Craig[/quote] I'm interested in doing something more substantial, but I wasn't planning on taking my HU out again for a while (until winter at least). Instead of custom circuits how about something like the PIE MPSS-4 or MPSS-2 [url]http://www.pie.net/sec11sb8.htm[/url], which should only need to be wired in (Better because somebody else has done the circuit design work/testing/etc) I haven't been able to find the competition but if there is a group buy we can probably arrange something so it isn't quite so expensive. That plus a small piece of ribbon cable and a socket. Forcing a cd-playing signal like I talked about earlier would need to be investigated, and may or may not need an addition circuit board. Probably just a transistor/resistor (if possible).
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.




×
×
  • Create New...

Important Information

Terms of Use