Volvo MultiMedia Module

Project about hacking my Volvo V70II to bring it into internet age and give it features you could dream about back in it's days.

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Summary of the project or what the goals are:

- God damn audio AUX input. Why they just didn't put that feature in? And if I'm on that, let's make it four! That's right. One AUX input? Toooooo lame. Four different ways of booming my playlist from my phone on car audio system? Jack cable, Bluetooth, Google Chromecast Audio...

- Backing camera. Yup I have huge estate car with screen in the dashboard. I can watch TV on it or have GPS. But TV is now all digital and who watches TV these days anyway. Let's throw away that TV tuner from last century and use screen for backing camera or even better. Place cameras in mirrors and use them to see into blind spots!

- Aaaand last but not least. 230V outlets, wifi on board and some relays in trunk for swithcing some cool equipment, just like flood lights when camping with car.

Let's get down to details in here.

Volvo V70II T5 (aka The beast):
There are basically 3 communication networks that one can mess with:

  1. High-speed CAN-bus (All important thing are here. Like engine, transmission, ABS... better not to mess with this network)
  2. Low-speed CAN-bus (Mainly not so dangerous features sit here like power windows, locks, interior lights, AC and so on.)
  3. MELBUS (Radio aka Head Unit and GPS navigation sits here. Really nice, simple and safe network to hack.)

MELBUS itself:
I was about to do some description on how MELBUS works, but i think that [fest] from made good work on this topic right here.

Hacking into MELBUS:
I originally used Arduino Nano (okay... do your booooos now) but then I switched to STM32F103 because running 12MHz bus onto 16MHz Atmega is just... let's not say stupid but rather awful idea. Well it worked, yes but reliability? You would rather spend all day getting FSO Polonez to run than this. Arduino is big no no for MELBUS. However after switching to STM32F103 everything started working just fine. Now i can emulate CD changer, read buttons that are pressed on HU and have HU think that there is actually CD changer. I'm getting ready for emulation of more devices.

  • 1 × STM32 Minimum system development board This is total heart of the system now. STM32 handles Volvo com-protocol and creates interface between everyting else and car.

  • Holidays, Engine break-down, PCBs and final SW

    werscajk10/04/2016 at 08:04 2 comments

    Okay I'm sorry for being quiet for three freaking months. I had holidays, traveled a bit and also ... my lovely turbo-charged 5-cylinder engine.. broke. Right after arriving home form 3000km road-trip. I parked the car and engine broke. What a luck. Could be worse. It drunk 2.5 liters of oil in 3000km trip, spitted all the oil around engine bay and MAF sensor retired. Long story short, after new PCV system and MAF installed, lot of gaskets replaced, new engine oil poured in, ATF replaced, 10hours of work and 1000USD lighter I can finally get back to work on this project.

    What's new

    1. PCBs for Audio AUX arrived
    2. VIDA / DiCE arrived
    3. FW for STM32 got finished (v1.0)
    4. HW for Audio AUX being finished

    1. PCBs

    That's right. PCBs arrived. Don¨t know what to say about these. Maybe some schematic would be nice. But I don't have that. To be more correct ... I have messy one and I don't fell like fixing that mess because function over beauty. I might draw a new one actually. But I'll provide gerber-file for PCB for sure. Here are few photos of PCB.

    Here is whole pack of PCBs. You know what is really nice? When you order 10 of them and you get 11 boards actually! So that is there 10% sale that manufacturer advertised. Not 10% off the price, but 10% more of product. I like that. 2.36USD per PCB. I really really like that.

    2. VIDA / DiCE

    I order VIDA / DiCE set for Volvo to get more intimate with car. I currently fighting with Vida to work. Guys that had honor with Vida will know the pain. For now I can only say I really fancy DiCE. Long cables, solid durable constriction and nice stickers on top and bottom. Hope I can say more, when I get this scan-tool working.

    3. FW for STM32

    I was able to finish SW for STM32 that will handle audio AUX. Currently it can fool HU-unit to think that CD changer is installed, switch between two or four inputs and send commands (Play / Pause / Vol + / Vol -) into Android-phone. Here is little demonstration in my short youtube video. I speak Czech there, but you will learn Czech really fast. I mean you will understand what I'm talking about from demo as I'm not saying anything that is not presented on video. There is no important information that is not written somewhere here.

    4. HW for AUX ECU being finished

    I'm getting HW finisihed quite soon. I had troubles with sound quality that can be noticed in video above, but resolution was easy. I put TDA1308 between HU-unit and my AUX ECU and problem was gone. I guess issue was that signal from the phone was low enough to be disrupted by MELBUS communication. Small headphone preamp solved it.

    And that's all the news for now. I hope to complete first out of 10 AUX ECUs. I'm so close to get AUX over cable finished. Next stop is bluetooh!

  • Core board protype

    werscajk06/29/2016 at 15:58 0 comments

    This project started on breadboard as everything does. After I was able to do some basic communication and had idea of what I expect from my DIY ECU i decided to create first prototype on protoboard that you can see bellow.

    This prototype has actually nothing special. It breaks out some pins, adds few resistors on MELBUS port and holds linear 5V regulator. This thing really got me going with this project. Then next thing was to feed audio from whatever to car. I again reached into drawer for more protoboards and created accessory for this core module. 4 channel stereo switch. What a lovely creation it is.

    Later on, I decided that using 2 wires is better than two and I added 2-bit address decoder to the relays. Then I started assembly....

    And then I stopped. I made "mistake" and published my project on local Volvo forum. I got feedback from several Volvo owners that they would like this thing too. I didn't feet like spending hours building several of these modules on protoboard, no. I decided to give it more of "like a pro" style. I designed PCB and sent it to PCB factory to make me several pieces for few bucks. 26 USD for 10 boards (FR4 1.6mm, 2 layers, blue soldermask, white silkscreen, HASL) to be more exact. You just have to love china. I would have to pay 26 USD for just one board if it was made in Czech Republic. So now I'm waiting for the boards to arrive.

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Discussions wrote 02/09/2018 at 20:07 point

very interesting project. Did you work further on it ?

Would you be OK to share your code for the STM32F103C8T6 CPU ? that would help me a lot

thank you in advance*


  Are you sure? yes | no

Daniel Wiegert wrote 11/14/2016 at 15:45 point

Hello again! How's it going for you?
I killed my Atmega and it was a bit too slow anyways so I'm moving to an ESP8266 module - but it just occurred for me - What are the voltage level on Melbus IO?


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werscajk wrote 11/15/2016 at 13:27 point

Hi Daniel!

Try STM32F103C8T6 instead. ESP8266 could be cool to have wifi but, STM32 gives a bit more of maneuverability in aspect of code. I'm working on AUX box. It's finished actually but I just work on polishing code and wiring, few last tests and audio AUX is mastered. 

About MELBUS levels. These are 5V !!!BUT!!! One Melbus line is 12V and that is RUN signal, that is always 12V if key is in Pos I or Pos II. This line says to connected device that car is on and that it should be on as well. I use this line to power my module, because it has lot of current reserve, it should be around 0.8 - 1 Amp.

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Daniel Wiegert wrote 10/03/2016 at 17:41 point

Any progress on this project? I am interrested in the software part.

Greetings from Halland, Sweden!

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werscajk wrote 10/04/2016 at 06:57 point

Sorry Daniel, I'm about to write a long log about project as there is lot of things that happened, but I'm short on time. I'll try to do it today! :)

Greetings from Czech republic


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Austin Marandos wrote 08/16/2016 at 04:34 point

Next step, add an autopilot system! Turn your volvo into a Tesla 

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werscajk wrote 10/04/2016 at 08:14 point

I like to drive my car myself. Honestly.. I thinks that Tesla is crap. However i dream about getting AWD version of V70 and installing it's rear driven axle on my car and drive that axle with electric motor instead of arbor from engine. That would be:
A) impractical
B) lot of work
C) damn cool
D) much fun
E) ruining automatic transmission

  Are you sure? yes | no

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