[MCahoon]

We use a smaller PIC (18F252) to interface to the SRF04 Ultrasonic module - handles the trigger/echo timing and converts to a digital input. I find it amusing that the SRF04 uses a small PIC to generate the ultrasonic pulses in response to the trigger, generating the echo pulse, which we measure with a 2nd PIC, so we can send the data to the PIC in the RC.