Easy: We just reuse the big rotary control already present in every car. Just press the Mode button on your steering wheel twice select Volume control accept with both brake and acceleration pedal being pressed for four seconds. Then steer left to increase volume and right to decrease volume. Press and hold the horn for mute.
A radio needs to be able to do two things: Rotate for volume and press for muting.
A dial button is not that hard to implement.
Plus it can work as a on/off switch.
Easy: We just reuse the big rotary control already present in every car. Just press the Mode button on your steering wheel twice select Volume control accept with both brake and acceleration pedal being pressed for four seconds. Then steer left to increase volume and right to decrease volume. Press and hold the horn for mute.