A couple of things:

1. Part of STEM at middle school level is "How things work". Computers including PIC's are "digital" - 1's and 0's. Each step away from pure machine language hides this basic fact. That physical phenomena like sound and light can be represented by 1's and 0's is my point. What is analog? What is digital? These are not part of this project, but it shows where I am thinking. (What is an echo and how can its response time be characterized in binary. What is hexadecimal?)

My PIC is on a prototype board inside the plastic body of a radio control car. This car body has holes for the two sonars, the six lead connector to which the USB connects, and for screw driver access to the speed controlling potentiometer.

Velocity is of the essence. Speed is the hook. That and the model level RC car's miniaturization of automobile mechanics. Turn over a model level RC car. Get in a grease pit and look up at a modern car.

The 1997 Cadillac Deville has 13 or more computers on board depending on which options in contains. Imagine the 2010 version. I think the 2010 Lexus car can back itself into a parallel parking spot. HOW DO THINGS WORK?

Ken