Steering Wheel Switches

[Orin Eman]

> The transmission was semi-auto with the up and down buttons on the steering
> wheel.  That made me think of the higher end cars in the late '80's.  There seemed
> to be a contest to see who could mount the most buttons on the steering wheel.  I
> think the Bonneville SEi had more than an F-16 cockpit.  I know each button didn't
> have a seperate ring in the steering column, so how did the switch signal travel
> from the steering wheel to where ever it went?  All my electronically limited mind
> can think of is either different resistances or capacitances or varying frequency
> signals.

I'd use a microcontroller and a serial protocol.  Three wires (2 power,
1 data) at most, though you could get away with only two if you
superimposed the data signal on the power lines!

Orin.