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What is an ultrasonic sensor

What is an ultrasonic sensor? Principles and applications of ultrasonic sensors in practice

Share all the knowledge related to ultrasonic sensors so that you can visualize the overview of ultrasonic sensors applied in industry and real life.

For example, an ultrasonic sensor is used to measure the level of a liquid to know if the liquid is almost full or al
most empty; Is there enough supply for the production line?

Or the application of ultrasonic proximity sensors to check objects on production lines such as forgetting to put stamps; labels, not well packaged products, or errors ……

Why do people use ultrasonic sensors so much and the importance of using ultrasound in today’s industrial revolution!

For example, in medicine, people use ultrasound to detect diseases such as kidney stones, check fetal development in cycles, etc.

What is an ultrasonic sensor?

The ultrasonic sensor in English, called ultrasonic sensor, is a type of sensor that emits sound waves that transmit many different environments such as liquid level measurement, wastewater flow measurement, fetal ultrasound, kidney ultrasound…

Besides; Ultrasound is also an electronic device that measures short distances, so it is also known as an ultrasonic proximity sensor to detect obstacles according to certain technologies.

To learn more about the structure and principle of ultrasonic sensor, what is it? You should take a look at its wavelength formation

What are ultrasonic waves?

Actually about learning the terminology

For English ultrasound, people call Ultrasound

And ultrasonic waves are called ultrasonic waves

As for the definition:

Ultrasonic wave is a kind of invisible wave and it can travel in any medium with a certain ultrasonic frequency. Especially; We cannot hear this type of sound wave at all if the frequency is below 16Khz, but we must monitor all measuring devices.

For example: Ultrasonic waves emitted by bats, Ultrasonic waves transmitted to the surface of the water, transmitted to the human body, ultrasonic waves of whales, etc. They all have different transmission frequencies.

A type of sound wave that the human ear perceives is one whose frequency ranges from 20hz to 20khz.


I was sitting at home and saw a car passing by. At this time, the sound coming from the car is the sound wave transmitted to my ears

For ultrasonic waves that cannot be heard by the human ear but can be heard and reflected by animals

Speed ​​of sound wave

The question posed:In the air-liquid-solid metal medium, which is the fastest propagation medium?

I assure you of one thing:When sound waves travel in metallic liquids and solids, the propagation speed is always much faster than in air.

Reason:For liquid or metallic media, the elements are tightly bound together to increase the travel speed of ultrasonic waves

Ultrasound waves travel in a vacuum?

Talking about ultrasonic waves, it is very diverse in terms of transmission lines. However; In terms of direction, this type of wave only goes in 2 directions:

Broadcast in vertical directionMove in the horizontal directionThe question posed:Can ultrasonic waves propagate in a vacuum?

There are many people who are confused about this issue!

And I assure you:

Ultrasonic waves are 100% sure not to propagate in a vacuumBecause the vacuum environment is a pure environment where no movement of the particles of the substance takes place.

But while sound transmission is always bridging from one molecule of matter to another (called sound conduction).It’s about sound waves. As for the problem of the sensor emitting this type of wave, it is a process of technological development

Ultrasonic sensor construction

The ultrasonic sensor is composed of three main components:

  • Sensor head
  • The threaded connection part and the place for the wrench to fix the device
  • Receiver and broadcast signal

The ultrasonic sensor head is 71mm in diameter and 62mm in height, in which:

The part containing the circuit board and the cap of the ultrasonic sensor is designed with an aluminum alloy with an integrated powder coating

Inside the circuit board is the circuit diagram + 2 positive and negative poles are the output signal output from the sensor

The display glass is designed with polycarbonate plastic

Body + transceiver design PP plastic

The area that converts the transmitted wave signal into an analog or rs485 signal of the ultrasonic sensor is integrated with a PVDF plastic layer.

For the type of ultrasonic level meter with integrated connection cable, the cable part is designed with plastic PA .

These are the basic components that form the structure of the ultrasonic water level sensor. Besides; For the measuring medium which is acid and chemical, the PP plastic layer of the body is replaced by ptfe . plastic

Working principle of ultrasonic sensor

As for sound waves from animals, it works on the principle of interferometry


The bat will emit sound waves to sense the sound waves emitted by a bee, for example. From sensing the sound waves emitted by the bee, the bat will chase to hunt for prey

Or broadcast bats encounter obstacles such as trees, houses, etc. Then the backlash signals it to avoid

As for the ultrasonic sensor alone, how will it work?

For industry, the purpose of using acoustic waveform sensors is to measure and report levels of liquids and solids.

Therefore; The principle of ultrasonic sensor will work according to the process of receiving and transmitting waves generated by itself. Specifically; when we install the sensor sensor into the water tank about 10 or 12m and supply 24v power to the measuring device

This time; the right part of the probe will emit a light in the shape of a V directed down to the surface of the water; After touching, there will be a V feedback back to the probe, then follow the signal wire to the output circuit board by 2 analog or rs485 output lines.

That is the operating principle of the transceiver that all ultrasonic sensors must be integrated into during production; to ensure the highest level of accuracy measurement

Application of ultrasonic sensor

For ultrasound, there are many applications. They are widely used in industry for liquid monitoring and in daily life

In real life, ultrasonic sensors are used in medicine such as fetal testing, kidney stone testing; application in home design

Industrial ultrasonic sensors for liquid monitoring applications; solid – gas, design and manufacture of obstacle avoidance robot

Here are a few practical uses of ultrasonic sensors to help us simulate the optimal function of this measuring device.

Ultrasonic sensor for measuring distance

Ultrasonic sensors are used to measure the asymptotic distance (near) of an object moving through the waves to ensure that there is no collision; keep a certain distance should be called ultrasonic proximity sensor or ultrasonic distance sensor


All ships are equipped with ultrasound to create a distance between the ship and the port, for example 1km. Then, when the ship returns 1km from the port, the sensor will alert the staff to notify the ship to reduce speed when docking to avoid a port collision.

Or use the door-mounted proximity sensor at the supermarket; when people approach the door a certain distance the door will open; People who go through the door will close by themselves

Obstacle detection ultrasonic sensor

Obstacle detection through ultrasonic is extremely optimized to avoid collisions without shape. Applications in military submarines, aircraft, vehicles avoid external obstacles also thanks to the use of ultrasonic sensors, …


Built-in ultrasonic distance detection sensor at the front and rear of the car helps the driver when backing up or turning if there is an obstacle nearby, it will notify through the image so that we avoid colliding with those obstacles.

Or ultrasonic sensors designed on submarines; help ships when moving under the sea to detect reefs to avoid collisions

Medical ultrasound machine

Ultrasound sensor is an electronic device that is applied in medical medicine such as: Periodic fetal ultrasound, ultrasound examination of foreign objects in the body such as gallstones, real stones, urinary stones, etc. imaging


People with hip pain, painful urination and bleeding but do not know what disease they will go to the hospital for an ultrasound of the abdomen to see if there is a stone clot or not.

Ultrasonic sensor for water level measurement

Measuring the water level with an ultrasonic sensor is also an extremely effective industrial application. Is an electronic device that replaces humans to monitor liquids in a production plant


A waste water tank is 6m high, users need to monitor the amount of water increasing and decreasing in the tank in units of liters of water.

In this case, using an ultrasonic sensor to shoot waves into the water, take a 4-20ma signal to the meter to display the linear water level according to the signal that the output sensor transmits to.

Ultrasonic sensor for flow measurement

Flow measurement by integrated ultrasonic sensor keeps the flow on the pipeline always stable with very high accuracy. This is a very cool traffic monitoring app


The amount of wastewater flowing in the DN50 pipeline and the factory they need is always within the range of 15m3/h, for example. Then the type of flow meter with built-in sound wave sensor is always the standard solution

Industrial ultrasonic sensor

Is a type of ultrasonic sensor designed exclusively for petroleum monitoring; Liquids, solids such as cement, sand, stone in today’s industries


Ultrasonic proximity sensor; ultrasonic wave sensor, radar ultrasonic sensor….

Fingerprint ultrasonic sensor

Integrated application on android mobile devices, handles opening and closing on doors, making timekeepers…. By using human fingerprint to scan


Fingerprint ultrasonic sensor integrated on the door handle. Mr. A installs his fingerprint on it, only Mr. A can touch his fingerprint to open and close the door; Besides that, no one can open it

Integrated fingerprint ultrasonic sensor on the timekeeper allows to install 1000 fingerprints on it. The job of the employee is to verify his/her fingerprint

When the worker comes to the company to work, he has to press his hand on it and when he returns, he also presses his hand. The sensor will record the time until the return time; the total number of hours worked by workers in the month to calculate wages

Advantages and disadvantages of ultrasonic sensors

The current; With a wide range of ultrasonic applications, ultrasonic sensors are quite popular

However; They still need to be further improved because each type of ultrasonic sensor has its own advantages and disadvantages

Waterproof ultrasonic sensor

A type of electronic device for use in which the level is resistant to the ingress of steam which can damage the equipment during long-term operation.

There are 2 types of waterproof ultrasonic sensors: The type that drops completely into the water to measure and the type that installs the ultrasonic sensor to place an area protected from water but integrates the ip68 standard against water ingress.

Waterproof ultrasonic sensor is designed according to IP68 standards, completely sealed in design, even at the output signal output terminal.

There are even application designs that require a sensor capable of sending submersible ultrasonic waves to measure levels or detect obstacles.

The disadvantage of the waterproof ultrasonic transformer is that the default measuring range we can’t flexibly set manually but can only be installed on plc or scada systems.

Analog Ultrasonic Sensor 4-20ma 0-10v

The analog ultrasonic sensor is a new innovation used in monitoring plant fluids or distances from which to output analog signals for control monitoring.

The advantage of this type of sensor is the variety of analog outputs such as 4-20ma, 0-10v, 0-5v, 0-1v… Always have high accuracy in measurement.

Disadvantages or interference cause loss of accuracy while monitoring by external factors such as inverters, affected by large capacity from motors, etc.

ultrasonic sensor hy-srf05 arduino

The arduino ultrasonic sensor is a low-cost electronic designed sensor circuit that is widely used in measuring object distances and returning results by displaying parameters on LCD.

The advantage of the arduino ultrasonic line is the ability to receive and transmit feedback for extremely fast actual measurement values

The disadvantage of the hy-srf05 ultrasonic sensor is that its measuring distance is very short, so the measurement process is very limited.

omron ultrasonic sensor E4PA-N

This type of ultrasonic sensor is designed with many different measuring ranges for solid – liquid – gas measurement, object distance. Originated from omron according to Japanese technology

Inside; The omron e4pa-n model is very commonly used, allowing multiple measurement ranges to be installed with a maximum distance of 6m.

The advantage of omron’s e4pa-n ultrasonic sensor is that it is not affected by the color of the measured object; multiple choice feeds; design a variety of frequencies; With a signal light, we can adjust the transceiver problem

Disadvantages accuracy is not high; many environments are not applicable

Ultrasonic sensor Turkey

An ultrasonic type of Turkish origin applied in liquid level measurement environments. This sensor is quite new in Vietnam

The advantage of this sub is not much, just a variety of level measurement ranges

The disadvantage is that the other accuracy is low. Made in Turkey, you know it and only use it in measurement environments that don’t need accuracy

Dinel . ultrasonic sensor

Dinel ultrasonic sensor is off the table because this brand of ultrasonic water level meter is too old and popular in Vietnam.

Advantages of dinel ultrasonic level probes high durability – flexibility in setting level measurement ranges – reputable distributor and always in stock – standard accuracy and quite cheap price

The disadvantage of ultrasonic dinel that needs to be improved is that the sensor’s heat resistance is only up to 70 oC – and it is recommended to integrate an additional ptfe coating outside for wide application in acidic environments.

ifm . ultrasonic sensor

Ifm’s ultrasound is mostly used in environments that measure distances to detect objects, and liquids are not very popular.

The special feature of the ifm ultrasonic sensor is that it can measure anything short and long distances – output signals are as diverse as analog, on/off – and the price is also very cheap.

The disadvantage of this type of ultrasound is not high accuracy – the structural design is still unspoiled – the temperature resistance is quite low.

So in short, to choose an ultrasonic level sensor, what issues should we pay attention to?

5 notes to choose a cheap ultrasonic sensor

Finding the brand and choosing the ultrasonic sensor is cheap only when we choose the right type; and make full use of its functions with optimal durability

As for the ultrasonic liquid level measurement line, it has many options for use in many different measurement environments. Each built-in option has a certain price

What exactly is the liquid to be measured? And how many meters high is the measuring range of the tank?

Check liquid temperature + area temperature to be measured

See if there are stainless steel bars in the liquid tank or if there are any obstacles inside. Because for ultrasonic sensors, the wave always emits a V shape with a transmission angle, so hitting an obstacle will cause errors

Besides; see what the output signal you need is, the measurement area if the range is low, you should use a level probe for the best solution.

Besides; A reputable supplier and warranty support after purchasing the ultrasonic sensor is a remarkable thing to save time when something goes wrong.

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