- The smartphone is connected to a (pretty crappy, but only 10 bucks) bluetooth audio receiver which is connected with a stereo jack to the cd charger input of my Alpine car radio. I had nothing to modify on this part.
- The display receives the song title and the artist name from the smartphone using a bluetooth communication. The Tasker app for Android is used to extract text from the notification (A notification is sent from the webradio every time a new song starts). I had to slightly modify an existing plugin from Tasker to send the text to a bluetooth spp module. An arduino board relays the text from the bluetooth module to a canbus module. The canbus protocol used to drive the display has to be reverse engineered.
- The steering wheel remote control (3x3 keypad matrix) is repurposed to a HID bluetooth keyboard to drive the smartphone (Home, ESC, Alt+Tab and Alt+Shift+Tab). I added a DPAD in a 3D printed case (up, dow, left, right and Enter) with a scrolling wheel to change the volume on the smartphone. (As a bonus, I'd like to use the + and - buttons of the remote control to the Apline radio unit). The HID bluetooth part is managed by a RN42 module connected to an arduino board (for keypad matrix decoding, encoder and dpad inputs)
Electronic hardware design : CERN OHL
The firmware and software are licensed under the GNU GPL