Ultrasonic HC-SR04 library for Arduino IDE Features: Compatible with the Arduino IDE 1.0.1 or lower 3 ms of TimeOut (51 cm) Support for more than one ultrasonic sensor English Wiki: https://github.com/elrodri/Ultrasonic-HC-SR04/wiki Spanish Links: http://www.ardublog.com/library-for-arduino-ultrasonic-ranging-hc-sr04/ http://arduino.cc/forum/index.php/topic,115077.0.html