Volvo low-speed CAN bus adapter

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.
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

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

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:

More information

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