I got tired of waiting, so I opened up the headunit itself and patched in to the CD output channels. (Kudos to OverLOAD, l8r and others for their valuable information.)

It wasn't too risky or hard (just a little soldering), it doesn't require any additional modules, cost about $10 (for the minijack extension.) The technique will work for either the Bose or base head units.

The result: seemless integration and perfect sound from my iPod. Next I plan to figure out how to pass the steering wheel controls to the iPod's wired remote input.

I'll post more info on what I did if anyone is interested.

 

Was it like adding inputs to the cassette player? and does is effect anything when you are playing a CD ?

Please post details, if it means taking a CD out and turning the iPod on, that's a great beginning and will work fine until Overload has the module we are all waiting for.
Thanks in advance and kudos.

 

It's pretty similar to the cassette hack. I tapped into the lines that feed the HU from the CD player. They are clearly marked (L, R, GND, etc.) so it wasn't hard to figure out where to solder. I have some pictures (unfortunately the one showing the exact soldering points was blurry). I verified that there was continuity from those points to the outputs from the HU using the schematic posted elsewhere.

Basically, the iPod and whatever CD you have playing share the channel, so I burned an 80 min CD of silence (which I titled: 4'33" extended remix, a Tribute to John Cage. =) Since I have a 40Gb iPod, I can't really see a situation where I'd need to bring my own CD, so there's no loss of convenience.

At this point, I no longer have a need for OverLOAD's module (it's still a valuable service for those who aren't comfortable with opening up the head unit) since I have pristine audio.

 

Sorry for my late jump on to this thread... I've been the on the car computer ones...

If the system in the 6 and RX-8 is basically the same there is no reason to think it'd be different in the 3. Cheaper for Mazda to use the same system over and over across all models.

The old modular stereo in the Protege is like that... used across all Mazdas of that model year... at least in Japan the Familia, Demio, MPV and Capella all had the same stereo and all have the same navigation system options.

 

I was thinking to ask the same question. As much of the reverse engineering is the product you are selling, I completely understand if you are unable to pass along any information, however, what I am looking at is not how to hack the head unit, but rather what kind of signaling is used to put messages on the display... does it still work (A/C and clock) is the HU is replaced or is some kind of "fooler" needed? what about the interface and signaling for the steering wheel controls?

Thanks

JMB

 

The signalling on the display is handled by the LCD controller and the connection to the LCD screen on the rear of the Head Unit. All the messages that this Aux-line-in (CD module, Tape, CDC, MD, etc) module uses communicate with the head unit to tell it what function it wants to perform. The HU then relays the message on to the LCD screen.

Still, it should be a relatively easy matter to send text to the display using the same method as the mp3 player once we get the test module to pump out the text, but it will require the use of the main HU bus, or you'll probably end up with display corruption.

OverLOAD

 

My hope/thought is to be able to display on the LCD without the stock HU and retain the steering wheels controls on a custom unit that is being designed...

 

That sounds like a much taller order. A big test would be to leave the LCD connector unplugged when you plug in your radio and power it up. It may just be the one segment area between the bars that says off, but I don't know for sure since I havn't tried that..

You'll need to know a lot of details and message structure, protocol details, checksum calculations, signal timing, etc. You'll probably need a custom electronic interface unit to handle that. If you can make it, it's a fun project, but it would be too expensive to buy, a real TFT LCD screen would be soooo much better

OverLOAD

 

I have. The LCD gets all of its input from the head unit.

edit: I should have written LED, not LCD.

 

Just to be sure... so that includes the A/C display data as well?

 

Just to clarify -- are you guys talking about the LCD screen (the one that has the nav display) or the LED display (the one with the audio, a/c, & temp info? I'm sure you mean the latter, but it does get a little confusing.

 

I'm refering to the latter... the LED display...

 

I meant LED. The LED gets all of it's input from the head unit.

If the head unit is removed from the car, the LED is completely non-functional.

 

That means reaplacing the HU, means new environmental controls.. They may still work, you just won't see what they do. That may be better to take full control over the LED Segment display, if you want to completely control it, but will probably mean that there is only 1 or 2 control lines for the display, and they are all managed by the HU software, that would eb a bummer, since the only way you could control the messages completely, is to intercept the HU-LCD bus communications, and only allow the messages you wanted to get to the LED to get through, plus inserting your own messages.. not impossible, but another big job.

If it was just the middle area between the lines, it might be easier. It could still be pin driven between the different regions though. If someone wanted to experiment with their harness it might be possible to figure out, but probably not too worthwhile.

I'm planning on going the other route, and telling the HU what messages to send, rather than intercepting the HU-LED communications.

OverLOAD

 

Aw F&#$%@! S*&^#@^#$!... it only figures. Ford group really plans to make aftermarket stereo upgrades EXPENSIVE.

In that case it is only a matter of time before a hack comes out in the aftermarket as having just a mounting kit is pretty useless with the environmental controls displaying nada. Just gotta wait for that bit of reverse engineeing to take place...

Thanks for the info guys!

 

I would bet that you wouldn't have to replace those. We do know that audio and HVAC are otherwise separate (separate chassis, separate controls). If there is just one connector to the LED display, and if it goes to the audio unit, then there must be some connection from the HVAC unit to the audio unit. If that's the case, odds are that the audio unit just passes the signals through, instead of processing them. So it's possible that all one would need to do is just connect those wires, bypassing the audio unit altogether.

Another thing to consider is the possibility that the LED display merely receives it's power from the audio unit (like the LCD and Japanese TV tuner units). In which case, even if it had a separate connection to the HVAC unit, it obviously wouldn't work at all when disconnected from the audio unit.

You can never tell, but I doubt that it's a setup where the HVAC sends signals to the audio unit, the audio unit receives and processes them, and then resends them in different codes to the LED display.

---jps

 

Yes, there are two of them at the HVAC unit that join at a connector to the audio HU.

Quote:

If that's the case, odds are that the audio unit just passes the signals through, instead of processing them. So it's possible that all one would need to do is just connect those wires, bypassing the audio unit altogether.

My thought exactly. A ground lead may have to be run in place of the ground to the audio HU, and maybe a power connection also.

Quote:

Another thing to consider is the possibility that the LED display merely receives it's power from the audio unit (like the LCD and Japanese TV tuner units). In which case, even if it had a separate connection to the HVAC unit, it obviously wouldn't work at all when disconnected from the audio unit.

I thought about that, but it seems unlikely, since LED displays do not require separate power -- the signal provides all the power needed.

Quote:

You can never tell, but I doubt that it's a setup where the HVAC sends signals to the audio unit, the audio unit receives and processes them, and then resends them in different codes to the LED display.

---jps

Agreed. That is just too convoluted for even an auto maker to do ... I think

 

I've got my HU on the floor here next to me, and the HVAC controls definately connect into the main face plate board, but I think that the harnesses that connect to the environmental controls don't go anywhere near the LED screen.

The smaller sideways connector in the back of the radio is the one that plugs into the LED display (According to the wiring diagrams) and it's the only one. The wires do route to the front of the face plate, so I would bet that the LED display controller is in the front plate. The HU itself is the piece that you take out of the radio to change out any of the modules (CD/Tape/etc) The LED control module is almost definately inside the face plate, and the HU talks to it through the front connectors for the button pushes, and the LED display update.

Or so I would believe.

OverLOAD

 

I "signed on" back on page one of this thread and was wondering if the March availability date still looked possible.

 

Yup. We're getting pretty close, and sorting out the last details. Early March is still our target and it looks like we'll probably manage to do it.

Regards,

OverLOAD

 

Sounds great! Can't wait...

 

That is great . . . the world awaits.

 

This sounds awesome.

Count me in.

Look forward to getting the ipod hooked up.

Will you be able to ship to the UK?

James

 

I havn't looked into it yet, but I don't think international shipping will be a big deal, you just have to take into account that there may be customs taxes charged on importing goods from other countries, so you'd have to pay whatever fees arose from that. Customs are never fun, and pretty difficult to avoid.

Regards,

OverLOAD

 

Any chance you can list all the features of your product? and on a scale of one to five, how easy will the install be (5 being the most difficult)