Just the word ultrasonic sounds cool to me! It makes me think of something fast, hi-tech, and hard to understand. Fact is, I think I'm right about everything but the hard to understand part, which I realized after purchasing the HC-SR04 ultrasonic distance sensor and hooking it up for a test run. I can think of a whole list of applications of this technology for my future projects; particularly for autonomous robots and UAVs (Unmanned Air Vehicles). Hopefully you have some ideas for your own projects too!
The concept of ultrasonic technology is quite simple. By emitting high frequency pulses of sound forwards, an obtrusive object would allow the waves to bounce right back to the source. If the pulse is in fact received ... read more at http://www.treehouseprojects.ca/ultrasonictutorial