Steering Wheel Switches

[Peter Fenske]

Hi Gang

GMs new radio controls use different resistances for differing switches
which go to a slip ring.

A A/D in the radio converts this to different signals.

HP in some of there test equips uses the resistances to
generate different current levels but this is not applicable
to slip ring operation.

gl:peter





Orin Eman <orin at wolfenet.com> on 11/16/98 10:22:40 AM

Please respond to diy_efi at efi332.eng.ohio-state.edu
                                                              
                                                              
                                                              
 To:      diy_efi at efi332.eng.ohio-state.edu                   
                                                              
 cc:      (bcc: Peter Fenske/BCIT)                            
                                                              
                                                              
                                                              
 Subject: Re: Steering Wheel Switches                         
                                                              









> 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.