His hardware hack of the SR04 made this a software problem which he also managed to solve! [Clint] was working with the Arduino library, based on the Parallax PING, which uses a single pin for trigger ...

This is an Arduino-based Proximity Sensor circuit wired using the popular HC-SR04 Ultrasonic ranging module,used here for non-contact object detection purpose. The HC-SR04 module includes ultrasonic ...