Unlike many cars today, Aykut Celik’s 2014 Volkswagen Polo didn’t have Bluetooth connectivity or an elaborate touchscreen navigation system. So, the Maker decided to take matters into his own hands and swapped out his “useless” radio for a Samsung tablet, putting Google Maps, Spotify and other apps right in his vehicle’s dashboard.
In order to accomplish this, Celik needed an amplifier (to replace the one attached to the prior radio), a CAN bus shield from Seeed (so he could use the steering wheel’s volume buttons), a Bluetooth module, and an Arduino Mega 2560 (for parsing data and sending it over to the Android device).
A CAN-BUS shield is necessary to be able to read CAN-BUS commands from the CAN bus line… I used this shield for detecting wheel button commands like volume up, mute and volume down. Behind the car radio there are two CAN bus cables. One of them is CAN bus – HIGH and the other is CAN bus – LOW. These cables must be connected to green sockets on the shield.
Using the SeeedCAN bus shield, you can sniff you car’s CAN bus data.
The info which is gathered from CAN bus is transferred to the Android tablet via Bluetooth. There is a little app which is responsible, for example, reducing volume whenever the wheel volume button is clicked. And a menu activity to open other apps.