Hello PICLIST

My suggestion to solve this problem would be to use an ultrasonic 
transducer, or preferably 2, pointed at an angle to the road, and together
with a pair of ultrasonic receivers utilize the Doppler-effect.
If it is made as a bridge, it should be possible to get a signal for even
very small movements.

The alternative would be a gyroscope, but then we are talking money - mucho
money!.

At 12.25 10-01-1997 PST, you wrote:
>How could you detect (for computer input) lateral movement from within
> an object when no contact can be made with the ground and there are no
> obstacles around to bounce a signal off of.
>
>For example: How would you detect that the rear end of a car has
> started to slide sideways (on ice) ?  The front wheels are still
> pointed forward (you have not started to turn the wheel to
> compensate).  There are no walls around to bounce a signal off of.
> Assume you have your breaks locked up and therefore cannot use
> comparison of wheel velocities.  Assume also, that you cannot attach
> any sensors to the ground, wheels or be manually activated.  Remember
> that most movement sensors would not be able to tell the difference
> between laterally sliding on ice and a sharp turn.  An optical sensor
> would detect ice but not that your sliding on it.
>
>How would you do it??
>
>Gene
>
>

Med venlig hilsen / Best regards

Poul Bundgaard              Phone    +45 86 65 13 92
Pr¾stev¾nget 4              Fax      +45 86 65 13 92
R¿dding                     Mobil    
DK-8830 Tjele
Denmark         E-mail:     p_bundgaard@vip.cybercity.dk