Definition of Ultrasonic Sensors and How They Work

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Ultrasonic Sensors Are ? Here is a complete explanation of what an ultrasonic sensor is, Functions, How it Works and examples of its use

You need a special tool when you want to measure distances with long range, sea depth, and detect the presence of metal. Such a tool uses the working principle of ultrasonic sensors.

In general, the use of this sensor is similar to a bat, which emits a sound and then receives a reflection. Furthermore, the distance calculation is carried out based on the travel time and the estimated speed of the sound. This is a depiction of how these tools and sensors work.

What is an Ultrasonic Sensor?


Images of Ultrasonic Sensors

The definition of an ultrasonic sensor is a sensor that works based on the reflection of sound waves to detect the presence of a certain object in front of it.

This type of sensor uses an ultrasonic sound of 20,000 Hz ++ to obtain a certain distance and time. In addition to measuring distances, the function of ultrasonic sensors is also capable of detecting cracks and types of objects that successfully reflect signals.

For example, a metal is given ultrasonically and as a result one part of the signal is returned well. Chances are that certain areas of the metal no longer have a perfect surface because there are cracks or damages.

Ultrasonic sensors consist of two units, namely the transmitting unit and the receiving unit. The structure of the transmitting and receiving units. Its working frequency in the area above the sound waves from 40 KHz to 400 KHz.

Components of Ultrasonic Sensors

  • Piezoelectric


Simple ultrasonic sensor circuits are not difficult to create. However, you need the right components and then connected to integrate with each other. The important part is piezoelectricity, which is a kind of electrical to sound converter. This is the source of the ultrasonic waves that are later emitted.

  • Transmitter 


The next component is a transmitter that is useful for continuing the sound wave signal that has already been produced. The tool can blend with the previous components or be made separately. In addition to serving as a transmitter, another function is a repeater or strengthening the signal to be able to reach a longer distance.

  • Receiver


The image of the ultrasonic sensor shows one special component called the receiver. This is the part that receives the bounce signal. There is a system where the transmitter and receiver are in one component.

Its use is more efficient but the range and sound capacity are limited. You better create a sensor where the receiver and transmitter are placed separately so that it is easy to measure data.

Functions of Ultrasonic Sensors


The basic function of an ultrasonic sensor is to convert electricity into a mechanic capable of producing sounds with predetermined wave frequencies. Here are 6 functions of ultrasonic sensors used in various industrial fields:

  • As Radar & Navigator

Navigator and radar are very useful in the field of military and transport. The military also uses these sensors to detect the presence of objects or anything nearby. The sensor is a source of data before carrying out the mission.

  • Robotic Navigation System

Certain robots for example metal detectors use sensors capable of emitting ultrasonic sounds. Its function is like a radar and a bat so that it moves without hitting anything hard.

  • Distance and Depth Measuring Devices

Arduino ultrasonic sensors are often used for simple distance measuring instruments. Tools like this are widely available for several needs from the daily level, for example knowing the depth of the well to more complex projects.

You can also make your own tool with the ultrasonic sensor component hc-sr04 integrated into a pc or laptop as a data processor.

  • Medical & Health Tools

Ultrasound or ultrasound is a tool in the field of medicine to check conditions in the body, especially pregnancy. The way it works uses the principle of ultrasonic sensors, namely sending waves live and then making interpretations of the reflection results in the form of videos.

  • Industrial Automated Systems

Ultrasonic sensors are also used in industry, namely machines and factories to process things. The existence of this sensor is very important for calibration and ensuring that there are no obstacles.

  • Mining Sector

Mining such as oil also uses detectors based on electronic sensors. This tool also serves to recognize the type of metal. When reflecting to a surface of an object, the result of the reflection will differ between one metal and another. With

Read Also Definition and Working Principle of DC Motor

How Ultrasonic Sensors Work


Image of How The Ultrasonic Sensor Works

Basically, the way ultrasonic sensors work  is to convert physical quantities (in the form of sound) into electrical quantities and vice versa. The transmitter sends a beam of ultrasonic waves, which will then be measured for the time it takes until the reflection of the object comes.

The working principle of the ultrasonic sensor uses the reflection method to calculate the distance between the object and the sensor.

The measurement of the distance of the object with this sensor can be calculated by the multiplication between the propagation speed of the ultrasonic sound wave on the propagation medium with the half the time that the ultrasonic sensor uses to emit ultrasonic sound waves from the transmitter circuit (Tx) towards the object until it is received back by the receiving circuit (Rx).

There are several points related to how ultrasonic sensors work that you need to pay attention to, what are the points? Please see below:

  • Ultrasonic waves

How ultrasonic sensors work based on sound waves of more than 20 khz. Humans can’t hear it but some animals like bats can catch the frequency. You don’t need to worry about the risks because the sound will not interfere with daily activities.

  • Transmitter and receiver

The sound comes from the transmitter and is then directed at a target. After that, the sound touches an object of solid density and is reflected back in a certain direction. Next, the receiver or receiver is in charge of capturing the result of the reflection.

  • Sound speed and time

Normally, the sound velocity is about 300-350 m/s which can be categorized as ultrasonic.

  • Measuring distances

From the data of ultrasonic sensors, you can estimate the distance between the sensor and the object that successfully reflects the sound. This calculation will be an estimate before conducting further research.

Overview of the Working Principle of Ultrasonic Sensors:

A piezoelectric crystal is connected by an anchor mechanic and connected only by a vibrating diaphragm. An alternating voltage that has a working frequency of 40 KHz – 400 KHz is applied to the metal plate.

The atomic structure of the piezoelectric crystal will contract (bind), expand or shrink against the polarity of the applied voltage and this is called the piezoelectric effect.

The contractions that occur are passed to the vibrating diaphragm so that ultrasonic waves occur that are emitted into the air (surrounding places). Ultrasonic wave reflection will occur when there is a certain object and the ultrasonic wave reflection will be received back by the receiving sensor unit.

Furthermore, the receiving sensor unit will cause the vibrating diaphragm to vibrate and the piezoelectric effect produces an alternating voltage with the same frequency

The price of ultrasonic sensors is actually quite affordable in electronics stores. This is a type of sensor that is often used for simple detectors. Products consist of various types and brands. You choose the one that suits your needs or buy a finished tool without having to string it from scratch.

The explanation of ultrasonic sensors is very useful for those who are interested in the field of electronics, electricity, and sensors. Its principle of action follows the system that animals such as bats have. More sophisticated applications can be found in specific fields such as medicine, military, and industry.

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