🚀 go-pugleaf

In sci.electronics, gpxpost@otago.ac.nz writes:

> The second sensor is a bit more tricky. I need to know the 
> orientation of the car, i.e. north-south-east-west. It would be 
> better if the sensor gave an absolute reference rather than relative, 
> then if the power fails the computer won't lose its orientation.

> On possible solution is to keep track of the steering wheel angle, 
> but this could be inaccurate. It depends on how fast the car is 
> travelling how much it turns, and it is possible for the car to skid, 
> then I don't know what direction it is facing.

> Anyone done this before, or got any ideas?

A US (California?) company called E-Tac(?) did something similar for
providing a moving-map display for motorists.  The first incarnation
used a rotation sensor on both front (or rear) wheels and derived both
distance travelled and direction (from differential counts).

If all you need is orientation perhaps some sort of compass, flux-gate
or otherwise.

    -Paul Bame N0KCL