I have a Parallax acoustical distance measuring module that works fine for measuring short distances. My application requires detecting an object that is positioned anywhere from about 2 feet to 70 feet. I am wondering if it is possible or has it already be done to write code that can make the device act as an active sonar unit. It would generate a ping sound that would bounce back to the detector when an object is in the path. I was thinking of generating the ping then read the sensor for the response just after the ping leaves the sender. It is not necessary to know the distance. I use a BS2.