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Volvo low-speed CAN bus adapter

<br> Some time ago I had installed the Android radio into my Volvo XC90 and had removed the all useless modules (phone, CD-changer, audio module, amplifier, navigation, antenna). I think the car lost weight :) I have got all nice android stuff, bluetooth connection to phone, video-in for the video recorder, sub-woofer out and etc. But I have lost the parking assistant(it works through Volvo audio system), steering wheel buttons. <br>So I have decided to make my own CAN bus adapter.

Features:

All information is received by low-speed car CAN bus, adapter works in Listen Only mode
Audio and navigation steering wheel buttons are mapped to two digital rheostats (sit to first, and six to second). It's simulated resistive buttons for Android audio
Rear gear output (0/12v)
Low ambient light detector output (0/12v)
Ignition key position I/II output (relay)
Parking assistant buzzer simulation (I've used central speaker)
Parking assistant control button allows to enable/disable parking buzzer

Hardware

Arduino Nano
MCP2515 based CAN bus adapter
MCP4231 double digital potentiometer
ULN2003A for digital outputs
12v relay

Schematic

PDF file

Software

<br>Libraries:

[Tone] (https://github.com/daniel-centore/arduino-tone-library)
[MCP4231] (https://github.com/jmalloc/arduino-mcp4xxx)
[MCP2515] (https://github.com/autowp/arduino-mcp2515) Has some changes, see forked version

<br>Forked libraries:

[Tone] (https://github.com/olegel/arduino-tone-library)
[MCP4231] (https://github.com/olegel/arduino-mcp4xxx)
[MCP2515] (https://github.com/olegel/arduino-mcp2515)

Compilation

I've used Visual Studio Code with Platformio extension. Clone code, update sub-modules. Open volvo.code-workspace file, build and upload. NOTE: each car has own CAN module Id! You should detect it youself.

My module:

Hardware

More information

More information you can find in my blog (Russian) (https://olegel.blogspot.com/2019/01/can-volvo-xc90.html)