Kerry Wong needed a way to determine distance in a project. A popular way to do this is to use ultrasound. Kerry is sharing his experience of building his DIY Ultrasonic Range Sensor so that the rest of us can learn from what he built. Parallax has a product called PING which is a popular way to allow your project use ultrasound to measure distance also. Only problem is when you purchase the module you pay more than if your built it from scratch and you don’t learn anything from the experience. This is only an argument for a hobbyist who is interested in learning from their projects as opposed to a system designer building a single project for a customer who just needs to glue some parts together and make it work reliably. Starting with a system that has been proven to be rock solid and building from it is the best way to succeed in making a robust product but there isn’t much learning that goes on. Kerry has provided code and schematics for anyone who is interested in building their own Ultrasonic Range Sensor.
“The theory behind ultrasonic ranging is quite simple. Typically a short ultrasonic burst is transmitted from the transmitter. When there is an object in the path of the ultrasonic pulse, some portion of the transmitted ultrasonic wave is reflected and the ultrasonic receiver can detect such echo. By measuring the elapsed time between the sending and the receiving of the signal along with the knowledge of the speed of sound in the medium, the distance between the receiver and the object can be calculated.”