An esp32 used as a2dp sink attached to the bmw canbus for steering wheel controls

• https://github.com/pschatzmann/ESP32-A2DP
• https://github.com/nhatuan84/esp32-can-protocol-demo

• ESP32: https://de.aliexpress.com/item/33004561102.html
• External DAC: https://de.aliexpress.com/item/1005004491534008.html
• CAN transceiver: https://de.aliexpress.com/item/1005002844175352.html
• AUX pinout adapter (not really necessary, since the external DAC has output pins to attatch to): https://www.amazon.de/gp/product/B009PH1IG4
• DC 8V-32V to DC 5V transformer: https://www.amazon.de/gp/product/B09B818N5F
• Random USB-A to USB-C cable

• CAN 3.3V -> ESP 3.3V
• CAN Ground -> ESP Ground
• CAN RX -> ESP pin D4 (GPIO 4)
• CAN TX -> ESP pin D5 (GPIO 5)
• DAC 3.3V -> ESP 3.3V
• DAC Ground -> ESP Ground
• DAC FLT -> ESP Ground
• DAC DMP -> ESP Ground
• DAC SLC -> ESP Ground
• DAC BCK -> ESP pin D26 (GPIO 26)
• DAC DIN -> ESP pin D22 (GPIO 22)
• DAC LCK -> ESP pin D25 (GPIO 25)
• DAC FMT -> ESP Ground
• DAC XMT -> ESP 3.3V
• ESP USB-C -> Transformer USB-A

Remember to short the pins on the can transceiver, if you don't need the 120 Ω resistor as an endpoint.

• Automatic reconnect to the last connected device is handled by the ESP32-A2DP-library

• Set volume on bluetooth connect automatically to the maximum of the bluetooth device

• a2dp can receive information about the song that is currently playing. You could attach a display to show the current artist and title.