I have not been planning on adding sensors. I might change the SONAR for IR. I know nothing about the details.

For speed I was planning on dividing distance traveled by time between measurements. For angles, I agree, the SONAR's have a vague and varying pattern. Hence the 'speed' calculations may be inconsistent.

With the hobby level car I have complete proportional control of both steering and wheel power. If I could get a PWM system that is truly 50htz (my present system is not. It was calibrated by trial and error) then I would have a great deal of flexibility - the better to speed up the car. Then a parameter passing GOSUB would be very convenient.

Ken