We have been working with a pair of SR04 ultrasonic sensors. We have the Newping sketches working with our cicuit. We seem to be having a slight problem. Once the object being detected becomes out of range, the sensor seems to get stuck on zero and does not seem to be resetting as it goes into the loop. We think this is a programming issue and not an issue with the sensor but we aren't sure. We'd really like to know if anyone had encountered this problem and how you solved it. We have an arduino uno for now and we have added an LED to our circuit. Thanks for the help!