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iPod Direct-connection successful! (but VERY difficult)


centerpunch

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[quote name='NoblePrawn']What are the costs like for one off prototypes and can you tell us who you've had success using? -NP[/quote] In small quantities, we have gotten simple boards in the $10-30 range. For a few hundred, the price would come down even more. Here are a couple places: [url]http://www.pad2pad.com/[/url] [url]www.protoexpress.com[/url] I am not sure which one we have been using lately -- I need to talk to the prototype guy here (he's out today) -- he has a program on his PC that is used to work up the design and then it gets submitted to the company and he gets the boards in a few days. Craig
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[quote name='Deer Killer']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).[/quote] Excellent idea! If we can get the custom part down to the flat cable, a connector, and some RCA connectors, the PIE device can do the rest. The hard part will be finding the flat cable and connectors -- so far I have not had any luck. Craig
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I'm sure [url]www.digikey.com[/url] would have the connectors-- sorry I didn't look into this before I put my radio back together. [url]http://dkc1.digikey.com/US/PDF/T043/CatalogPages.html[/url] They have jacks and short jumper cables. Maybe start on page 48. You'll need to measure the pitch of the existing flex cable (the distance between conductors).
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Cool, when I looked before I was searching on ribbon cable and didn't find anything. If you search on "flat flex cable" a bunch of stuff pops up.... I need to pull the radio once more to finish my RF modulator install, so maybe I can get more details on the cable. Craig
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OK, looks like the pitch is 1mm -- it's the only size that would physically make sense for the number of conductors and the approximate size of the cable when I peeked in the radio last week, and it's the only type pf cable that matches all the other specs I have researched. So we have 1mm pitch with 14 conductors. The cable is on page 49 of the DigiKey catalog, by Parlex. The connectors are on page 52, by Hirose. Craig
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Here's what would probably work: [img]http://members.cox.net/craig.hunter/ipod-subaru.jpg[/img] It would require two flat flex connectors, DigiKey # HFF14TND ($0.76 each for 1-9 pcs) and an 8" flat flex cable, DigiKey # HF14U-08-ND ($4.50 each for 1-9 pcs). Then a couple RCA L/R pair audio cable ends, one end male one end female (meaning it may be possible to hack up a single cable pair and use the ends). The audio cables would spill out the back of the radio and connect to the PIE switcher (we need to get ahold of one of those and see exactly how it would work in this case). It's looking like $10-15 in parts and $39 for the PIE switcher, and then whatever the circuit board costs to integrate it all. Craig
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I think the jumper wire will want to be alot shorter than that. (But I could be wrong).

 

There's a small plastic cover glued onto the rear heatsink covering an opening about 1/2" x 1/2," which is probably where the antenna connector would be (if the radio had a conventional antenna connector).

 

That just peels off, and the opening is a great place to bring out the 4 cables.

 

Low-technology sketch attached.

jumper.thumb.jpg.4a8614eec03d3d354729689e21deb373.jpg

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Excellent, that's exactly what I was thinking! (nice drawing btw). One thing I am grappling with is where the "intermediate" board would sit -- like your drawing, I was thinking it could float in space ideally (with a 1-2" flex cable instead of 8") but this might not hold up well over time -- it would probably flop around and be asking for trouble. I think we can get the board fabbed with the connecters and rca jacks in place. I have not seen any rca pigtail type connectors in DigiKey, but they have a nice selection of board mount rca plugs (pg 259-260). *IF* that spare opening in the back of the radio were able to accomodate 4 rca jacks we'd be golden, but I don't think it will. I bet it would accomodate two mini-jacks (ie; 1/8" headphone plugs) though. So really, the size and organization of the board will depend on where it can be mounted in the radio and what kind of output jacks can be fabbed with the board. Craig
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The difficulty with that is making connections to the cut segments of the cable. It's a fragile, solid, thin, flat conductor, difficult (at least!) to strip and very difficult to connect to. I think the PC board would more than pay for itself in terms of time and reliability. I also think you still need two 14-pin sockets- one to plug the existing cable into, and one to plug the jumper into. Then you need to connect 11 pins of each together. I doubt if anyone could make any money on this project, but if indeed someone does, my kudos!
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Yeah, I think the best we should shoot for is a group buy on the assembled boards. With this kind of thing, you save big bucks in quantity. As noted, the board will make life a lot easier. Another possibility is to join two connectors with conventional ribbon cable, which would be easier to work with and split/splice with rca cables. However, the solder pins on the connectors are spaced 1-2mm, which is kind of tight to work with. That's sort of why I think it would be easier to have it fabbed. Craig
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I took a look inside my radio today as I was finishing up my RF mod install. Turns out that the flat flex cable can (FFC) also be disconnected at the CD changer. That opens up more possibilities for integration. There are several good mounting locations for a small circuit board with the FFC connectors and leads to rca cables. It ought to be possible to mount the board to the inside of the radio box with some double-stick tape. Then the rca cables could be run out the back of the radio. Craig
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Great information guys! I was going to get around to experimenting with this myself soon! I think it would be nice to trick the radio into thinking it was playing a CD instead of really playing one. Playing a silent CD is still going to use up the laser to some extent. Perhaps with more testing, the circuit can be modified to deal with the radio as if it was a CD player when active. I look forward to more posts!
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Trent, Yes, that would be even better! Based on centerpunch's research, there is some sort of play/mute signal communicated between the CD changer and the radio, which may be the same as the general "playing a CD signal" that gets passed between the two. If we can tap into that, all the better! Centerpunch found the three audio pins, so there are 11 remaining unknown pins to deal with. When I think about all the commands that get passed over those 11 pins, it seems like it might be difficult to isolate what we need. There is play, skip-forward, skip-back, load, eject, switch CD, repeat, and probably another couple I can't think of at the moment. I am sure there is some sort of communication interface there, so it almost makes me think we need schematics or other engineering documents to go any further. There might not even be a dedicated CD on/off pin -- that could be part of the logic communicated through the interface. Rather than get the boards made now, I think it is worth waiting for someone to take the next step and work out the remaining interface details. Hopefully the info in this thread can get us to the next step. Going a little further, it may even be possible to communicate track skip signals back out of the interface, which could then be sent to the iPod or other device. I bet the folks at iceLink could do this all in a heartbeat. I don't think their kits are intended to connect internal to the radio, but it's the only option in this case. We basically just need an iceLink type kit that goes inline with the internal flat flex cable rather than plugging into an external CD-changer jack like usual. Other than the connection detail, the rest is straight-up iceLink-type of device. Craig
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Well, I'll contribute what I can! We already know that there is at least a Right, a common, and a Left for audio use. Most likely, there will be a Power ground and positive. So thats 9 left over. [u]Up to this point I was being a smartass and stating the obvious but it won't come across well so I'll continue seriously.[/u] One of those will probably be a data bus ground. (I think we can assume that there's probably a data bus as Craig said. There's too many functions for the remaining 8 wires to handle most likely. Or is there?) I'm not familiar with iceLink, but from what I've read here, it does sound like they could probably handle it. With all of these radios being taken out and pulled apart, has anyone noticed what brand they appear to be? We already know that the factory sub is a Panasonic. Is it probable that the rest is too? I would think so.
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I'm telling you guys, the "silent CD" (cost: 10 cents) system I used seems to work perfect. You could add electronic automatic switching by spending a lot of time learning how to communicate with the CD player and radio by examining the signals on the other 11 pins in detail, and developing circuitry or purchasing an outboard adapter to do all that, but that really will only add expense, without making the adapter work better in any significant way. When I get in my car, I turn on the car radio (which is in the middle of playing the silent CD from the last time I was in the car), and press the iPod's "Play" button. That's it! Or to play a CD, I just select any non-silent CD in the player, and then I don't press the iPod's play button. How could it be easier to use than that! Make a small single-sided circuit board with 2 audio jacks, 2 flex cable connectors, six resistors, and four capacitors, add a short 14 conductor jumper from Digikey, and the parts cost would be very low. And with the resistors and capacitors on the PC board, the only cable that has to come out of the back of the radio goes to the iPod. And the design is already done! Someone could sell the kit for maybe $50, and convert radios for maybe $150 (disassembling the radio takes some time!), and maybe make some money while they make a bunch of Legacy owners happy.
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I agree with you centerpunch, but I think we're learning so much so quickly right now, it can't hurt to wait a while longer in case any new info pops up. The thread is less than a week old and look at how much we have learned!! I would not be surprised if someone else came up with a couple more important tips. Trent, the radio in my OB XT is by Matsushita. It had the following part numbers: 86201AG61A and CQ-EF1461L written on the sticker. If there's a way to get a repair manual or schematics based on these part numbers, that would probably give us all the info we need. Craig
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c_hunter, Matsushita is the manufacturer of Panasonic, Technics, Quasar, Zenith I think, and a few others. Out of the sub-companies that I'm aware of, I'd guess that the Legacy stereo is all Panasonic. It's too bad they didn't include an "Ambiance" switch. I always liked Panasonic's "Ambiance" mode! (It probably over-processed the sound a great deal though.) centerpunch, I like the simplicity of the silent CD, but I've seen way too many worn out lasers to feel comfortable with it myself for too long. If it's going to be running all of the time, I kind of feel that I should at least be hearing something from the CD itself. Otherwise, I'd like to see the CD motor stopped and the laser off to extend their lives. I'm really excited to see these new ideas and a working method, but I'd like to see further development as well.
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[quote name='centerpunch'] Also, I've never had a laser burn out in any CD player, and until I recently got my ipod, my CD players already played continuously......[/quote] I'm surprised! I'm careful not to get dust and fingerprints on my CD's, I always hold them by the edges, never flex them too much, always use the cases or a holder of some sort, etc. and I've got a collection of units that skip frequently even though the lens has been cleaned. Lasers tend to have a life expectancy of a certain number of hours. For example, 50,000 hours for unit A and 40,000 hours for unit B, and so on. (I don't have any actual specifications in front of me, but I'm sure you see the point. Perhaps someone else has this info available?) One of my other cars had a CD playing in it almost all of the time like you appear to do. I have the laser transport unit bubble wrapped in a box just a few feet away that I need to send in to get the laser replaced. It lasted roughly 4 years of very frequent use. I've got 2 Denon head units with weak lasers that work okay on a table but skip like crazy in a moving enviroment. And I've replaced WAY too many CD-ROM drives because the lasers were too weak to reliably read a CD. Once in a while a spindle motor will give out instead. I think what worries me most at this moment with this particular car is all the reports that I've happened across regarding the failures of the indash 6 disc changers in recent Subarus. Maybe it's a geographical phenomenon? The air's thinner here! :) In any case, despite the inferior sound quality, an FM modulator doesn't put unnecessary wear on the CD unit. I'm inclined to stay with that method a bit longer to see what may come. Never had a laser wear out, huh? I'm really surprised to hear that! Everyone I know has had it happen at least once. P.S. - Regardless of my concerns, I really appreciate the work done towards this cause!!!
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