tag:blogger.com,1999:blog-92123069620613247692024-03-05T06:12:37.298-08:00Audi Concert Autopilot HackLazerjuleshttp://www.blogger.com/profile/01005674214422581156noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-9212306962061324769.post-24976677489326892932010-08-12T11:23:00.000-07:002010-08-14T12:35:58.706-07:00Audi Concert Autopilot Hack<div style="text-align: justify;"><span class="Apple-style-span"><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">If I wanted to listen to my ipod with my 10 year old Audi Concert stereo I used one of those tape adapters, you know the ones, they look like a cassette with a cable coming out. It worked, but as you all know they are not exactly hi-fidelity, although I would say the results were slightly better than the FM transmitter type. It was a neat install, the cable went above the head unit and you couldn't tell it was there. But I was getting considerably frustrated with a) the quality of the tape adapter and b) the rattle, clunk, clunk, rattle that the tape device made when in the deck.</span></span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">As someone who believes there is always a better way and a mod to be made, I decided that in true hacker style I would take matters into my own hands.</span><br />
<span style="font-family: Arial;">The main reason for taking this approach is because I want my car to stay as OEM as possible. Yes I could have bought various new off the shelf units with all these features and more, but I wanted to keep the original look. The car is an Audi TT, whose interior is a classic design.</span></div><span class="Apple-style-span"><span class="Apple-style-span" style="border-collapse: collapse;"></span></span><br />
<div style="text-align: justify;"><span style="font-family: Arial, Helvetica, sans-serif;">First, the head unit came out and I set it up on the bench with a bench PSU and </span><span style="font-family: Arial, Helvetica, sans-serif;">some old hi-fi speakers, off came the lid and I ripped out the entire cassette </span><span style="font-family: Arial, Helvetica, sans-serif;">mechanism. Second, I needed to fool the head unit into thinking it's in </span><span style="font-family: Arial, Helvetica, sans-serif;">tape mode. The Concert head unit is, as I am sure many other are, quite </span><span style="font-family: Arial, Helvetica, sans-serif;">particular in the way it tests to see if there is a tape inserted; first it </span><span style="font-family: Arial, Helvetica, sans-serif;">looks for a physical tape, then it checks the tape is ok by measuring </span><span style="font-family: Arial, Helvetica, sans-serif;">the load on the drive motor. So, the next trick was to fool the head </span><span style="font-family: Arial, Helvetica, sans-serif;">unit into thinking that there is a tape in it, so that when you select </span><span style="font-family: Arial, Helvetica, sans-serif;">the tape source it actually stays on.</span><br />
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<span style="font-family: Arial;">This ended up being easier than I thought, I went down the track of trying to work out the logic sequence of the mechanism switches and motor sent to the TDA3612 tape control IC, which is mounted on a sub-board. But I discovered that actually all the control IC was doing was setting an enable pin on one of the main processors once it was happy. The slight complication was that I couldn't just leave the enable pin permanently set. When you enter tape mode using the source button, a small time delay of a second or two was needed before setting the enable pin, without the delay the unit would reject being in tape mode and return to radio. </span><br />
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<span style="font-family: Arial;">I discovered by scoping around that one of the pins on the Dolby processor was set high when tape source was selected, but it was an instantaneous change of state, so I programmed a PIC12F629 that I had lying around to provide a delay, triggered by the enable pin on the Dolby chip and then using an output from the pic to control the enable pin on the processor. A bit of an overkill for the job but simple, reliable and requiring no external components, I also thought that should I need to add any other logic functions, I could easily expand the use of the PIC.</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2f7j-96vXJM7lATUZRlM0Lk-DH89QQPe27K4-SphUpH5U6GagVCrYltLg5WxQjzzYf4ke4gQ3ZjZH2pasRukia8zvqPnKDuvOj_B2WQVv_DQr8Z_h9G5BEKrTv2yxJsrMAyjLhluHP4K7/s1600/IMG_0625.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: Arial, Helvetica, sans-serif;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2f7j-96vXJM7lATUZRlM0Lk-DH89QQPe27K4-SphUpH5U6GagVCrYltLg5WxQjzzYf4ke4gQ3ZjZH2pasRukia8zvqPnKDuvOj_B2WQVv_DQr8Z_h9G5BEKrTv2yxJsrMAyjLhluHP4K7/s400/IMG_0625.jpg" width="400" /></span></a></td></tr>
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</tbody></table><div style="text-align: justify;"><span style="font-family: Arial, Helvetica, sans-serif;">Next I needed to find out where the line level signals were, I </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">didn't just want to attenuate the ipod line level and connect to the tape </span><span style="font-family: Arial, Helvetica, sans-serif;">head as the input to the Dolby processor is high gain and the IC </span><span style="font-family: Arial, Helvetica, sans-serif;">obviously processes the signal as well. I discovered that on the main board there is a main audio control IC, a TDA7342, which acts as a source selector as well as having other functions, so I traced the output of the Dolby processor to the TDA7342. I completely removed the </span><span style="font-family: Arial, Helvetica, sans-serif;">surface mount Dolby chip and tapped into it's output lines. </span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">Initially </span><span style="font-family: Arial, Helvetica, sans-serif;">I had difficulty with the DC coupling between the ipod and the head unit, </span><span style="font-family: Arial, Helvetica, sans-serif;">I could either charge the ipod or I could listen to it, but the </span><span style="font-family: Arial, Helvetica, sans-serif;">connection of both together sent the ipod into reset. The head </span><span style="font-family: Arial, Helvetica, sans-serif;">unit does not seem to have a virtual ground, but after trial and error and </span><span style="font-family: Arial, Helvetica, sans-serif;">the addition of two audio grade 1uF bipolar decoupling capacitors, one in series with each channel from the ipod to the inputs of the TDA, the system worked perfectly. The </span><span style="font-family: Arial, Helvetica, sans-serif;">capacitors did not degrade the audio significantly enough to worry </span><span style="font-family: Arial, Helvetica, sans-serif;">about, which was a concern at first as the decoupling capacitors are also acting as a high pass filter.</span><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif;">Removal of Dolby Processor</span></td></tr>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif;">Experimenting with line input.</span></td></tr>
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<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/_c-sYXt-pRgQ/TGQRNLeBBBI/AAAAAAAAAB8/cfbfifFvC9k/s1600/Autopilot.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><span style="font-family: Arial, Helvetica, sans-serif;"><img border="0" src="http://4.bp.blogspot.com/_c-sYXt-pRgQ/TGQRNLeBBBI/AAAAAAAAAB8/cfbfifFvC9k/s320/Autopilot.jpg" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif;">Griffin Autopilot</span></td></tr>
</tbody></table><div style="text-align: justify;"><span style="font-family: Arial, Helvetica, sans-serif;"><span class="Apple-style-span" style="border-collapse: collapse;">In order to graft an ipod/iphone into the head unit, I used a Griffin </span><span class="Apple-style-span" style="border-collapse: collapse;">Autopilot device. The Autopilot has an ipod connector on the end of a </span><span class="Apple-style-span" style="border-collapse: collapse;">cable, it allows charging, play, pause, FWD and RW along with connection to the line level output of the ipod. The Autopilot has a 3.5mm jack socket and an output level switch. </span></span><span style="font-family: Arial, Helvetica, sans-serif;"><span class="Apple-style-span" style="border-collapse: collapse;">The device is packaged as a cigarette style plug in </span><span class="Apple-style-span" style="border-collapse: collapse;">adapter but of course I didn't need all the dressing. </span></span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">After stripping it from it's casing I installed it into the </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">void the tape mechanism used to occupy, using my favourite modding tool, the hot glue gun! </span><span style="font-family: Arial, Helvetica, sans-serif;"><span class="Apple-style-span" style="border-collapse: collapse;">I didn't need to modify the Autopilot, it was just a matter of hard </span><span class="Apple-style-span" style="border-collapse: collapse;">wiring the switches and line out into the head unit.</span></span></div><div style="text-align: justify;"><span class="Apple-style-span" style="border-collapse: collapse;"><br />
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<div style="text-align: justify;"><span style="font-size: small;"><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif; font-size: 13px;"><span style="font-size: small;">Another nice feature of the Autopilot is that it has four bi-colour</span> </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">leds on it, these show the charging state, red when charging the ipod </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">and green when fully charged, as the board is mounted behind the </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">now unused cassette door, a subtle halo like glow is emanates</span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;"> from the head unit which visually indicates the ipod charge </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">status.</span></span><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px;"><br />
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<div style="text-align: justify;"><span style="font-family: Arial, Helvetica, sans-serif;">In order to use the control functions I hard wired some of the buttons on the front panel </span><span style="font-family: Arial, Helvetica, sans-serif;">of the head unit; the REV button on the front is now the Play/Pause button and the Dolby </span><span style="font-family: Arial, Helvetica, sans-serif;">and RD buttons are Forward and Back respectively, but as these buttons </span><span style="font-family: Arial, Helvetica, sans-serif;">were only relevant to tape operations that no longer exist this is ok. </span><span style="font-family: Arial, Helvetica, sans-serif;">Unfortunately this is the untidy part of this mod, the buttons are wired as a matrix and connected to a decoder which is on the front PCB, I had to use some fine enamel coated wire to tap into the switch lines. I know I could have probably done something fancy and decoded the data with a signal analyser, programmed a PIC and tapped into the main data bus, but I think that is a little unnecessary in this case. </span></div><span style="font-family: Arial, Helvetica, sans-serif;"></span><br />
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<div class="separator" style="clear: both; text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif;"></span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5YcDs99CeH0_fioZ_Kb38ujlXVUHJ7L_ILIYouxk6vVn8AqM-y_HMxrzbxn5xJphraFRNKkux9p_477PFQDaJe0qC6uEAuQ3uvkPCJdq6hHETYD9WzFYeRs572hSj-rc8KDpqHxqyBEm6/s1600/IMG_0666.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5YcDs99CeH0_fioZ_Kb38ujlXVUHJ7L_ILIYouxk6vVn8AqM-y_HMxrzbxn5xJphraFRNKkux9p_477PFQDaJe0qC6uEAuQ3uvkPCJdq6hHETYD9WzFYeRs572hSj-rc8KDpqHxqyBEm6/s400/IMG_0666.jpg" width="400" /></span></a></div><span class="Apple-style-span" style="border-collapse: collapse;"><br />
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<div style="text-align: center;"><div style="text-align: justify;"><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">Is it any good? Yes it's absolutely fantastic! Don't get me wrong, it's no Alpine and it never will be, but considering it was only the cost of the Griffin Autopilot, it is an amazing improvement. I need to iron out a few bugs, at the moment the output of the PIC never gets switched off which means that if you switch back out of tape mode you cannot then select tape mode again untill you power cycle the unit. This is a minor bug fix, I just need to edit the code slightly. But overall well worth it. The few pics were taken during my testing and prodding. </span></div><span class="Apple-style-span" style="border-collapse: collapse;"><br />
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<div style="text-align: justify;"><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">I wanted to add the FIPO device by Anycom. This is a bluetooth adapter that plugs into an ipod dock, it allows bluetooth streaming of audio from an ipod to a dock, whilst also allowing wireless control. </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">The idea being that the iphone stays in your pocket, when you get into the car it will automatically connect and allow wireless audio/control. </span><span class="Apple-style-span" style="border-collapse: collapse; font-family: Arial, Helvetica, sans-serif;">The device is easy to setup, has a very small footprint and whilst it does stream audio, I just could not get the control functions to operate correctly. No matter how many times I paired it with an iphone, the FWD/BACK controls just wouldn't work. I wonder if it is just incompatible with the Autopilot?</span></div><div class="separator" style="clear: both; text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif;"></span></div><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: 1em; margin-right: 1em; text-align: center;"><tbody>
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif;">Anycom FIPO</span></td></tr>
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<span style="font-family: Arial, Helvetica, sans-serif;"></span></div>Lazerjuleshttp://www.blogger.com/profile/01005674214422581156noreply@blogger.com