Ultrasonic sensors work by transmitting energy in the form of ultrasonic waves to a target object, which reflects the waves back to the sensing head. Ultrasonic sensors are largely used in measuring distances based on the time it takes for the wave transmission and reception to be completed.
The energy transmitted by an ultrasonic sensor to an object comes in the form of ultrasound, which is a sound wave above what the human ear can perceive. Ultrasounds are generated by an ultrasonic transducer that transmits ultrasonic waves coming from mechanical energy produced by air blowing.
A basic ultrasonic sensor is composed of a transmitter and a receiver. There are two general types of ultrasonic sensors, differing only in the material used to generate the wave. The first is a piezoelectric sensor, which generates ultrasonic waves through piezoelectric quartz crystals or ceramics. The second is an electrostatic sensor, which makes use of a micro-thin metallic membrane.
Ultrasonic sensors can be used for detecting levels of liquid content in a tank or container. The sensor emits the wave towards the liquid surface, which bounces the wave back to the sensor receiver. The data is sent to a system to calculate the liquid level based on pre-programmed information about the tank's full level. More advanced uses of ultrasonic sensors are found in the field of medicine, particularly in medical ultrasonography, which is used to detect the fetus inside a mother's womb.