The steering wheel buttons need a way to connect to a something that converts their momentary presses to an analogue value, and the momentary Honda Econ button needs a way to become a latching switch.
Arduino + XBee to the rescue.
Everyone knows Arduino – Atmel MCU on a standardised board with simplified programming environment. Reading inputs and latching outputs or driving PWM or a DAC are fairly straight forward. Things like CAN bus shields (add-on boards) come in handy when integrating with existing networks and displays such as the BMS / OBD2 network. But what’s XBee? It’s a small module that makes wireless IO and serial transmission super easy.
Wireless? Yeah, because having those spiral cables the race guys use to connect the steering wheel buttons is kinda annoying for a street car. The little XBee module can sit behind the bottom spoke of the steering wheel and wake up to send button presses to the peer XBee connected to an Arduino module behind the new console panel. Just have to optimise for power consumption and rig up an LED or something to warn when the battery needs replacing.
The Arduino with CAN bus shield can send CAN bus messages for Regen value and Econ mode for Torque to display.