This device built by [Danilo Abbasciano] uses a Parallax Ping sensor instead. If the sensor is placed at the top of a well, cistern, or other water container, it can accurately calculate the ...

Longer term he wanted to have the choice of either a Parallax PING or MaxBotix ultrasonic sensor for their better performance outdoors. His hardware hack of the SR04 made this a software problem ...

He uses Parallax ping sensors connected to an Arduino to measure whether you're in any danger from nearby obstacles and traffic. The red and green LED indicators are hooked up to ambient light ...