What is Ultrasonic Sensor: Working Principle & Applications

Summary

Are you looking for an accurate, reliable, and cost-effective way to measure the distance, level, or presence of an object?  If the answer is Yes! Consider an ultrasonic sensor. This blog post covers what it is, the principle of working, how it is used and its applications Ready to learn more?  If you want to learn more about these amazing devices, then keep reading!

What is an Ultrasonic Sensor?

The Ultrasonic Sensor is an electronic device which measures distances by sending out sound waves and collecting the returning echoes. It can measure items up to 4.5 meters away, making it a versatile tool for measuring both short and long distances accurately without contact with the target item - essential in many applications such as obstacle avoidance systems in robotics or autonomous vehicles. The sensor features adjustable pulse widths, allowing for higher resolution measurements when set at lower levels though this comes at cost of range accuracy diminishing as a result; however due to its affordability compared other forms of distance sensing technologies makes it incredibly suitable where budget constraints are paramount factor within projects evaluating solutions using ultrasonics technology.

 

 

Ultrasonic sensors are used as proximity sensors. They can be found in parking technology and anti-collision safety systems. Ultrasonic sensors are also used in robotic obstacle detection systems and manufacturing engineering. Compared to infrared (IR) sensors in proximity sensing applications, ultrasonic sensors are less susceptible to interference from smoke, gases, and other airborne particles (although the physical component is subject to variables such as heat). 

 

Ultrasonic sensors are also used as level sensors to detect, monitor, and control liquid levels in closed vessels (such as chemical plant drums). Most notably, ultrasound technology has enabled the medical industry to image internal organs, identify tumours, and ensure the health of babies in the womb.

Principle of Ultrasonic Sensor

The principle of ultrasonic rangefinders is to measure the time it takes 

the signal sent by a transmitter and propagated back to the receiver. As the name implies ultrasonic sensor operates on ultrasonic frequencies. Frequencies beyond our hearing range are known as ultrasonic frequencies. Those frequencies are above 20k Hertz. 

 

They are the all-rounders of sensor technology and can be used in any industrial application. There are several types of objects that can be detected, including solids, liquids, granules, and powders. They reliably detect transparent or glossy objects, as well as objects whose colors change. 

 

How Ultrasonic Sensor Works?

An ultrasonic sensor is an electronic device that measures the distance to an object by emitting ultrasonic waves and converting the reflected sound into electrical signals. Ultrasound travels faster than audible sound (that is, sound that humans can hear). An ultrasonic sensor consists of two main components: a transmitter (which uses a piezoelectric crystal to emit sound) and a receiver.

 

While some sensors use separate sound emitters and receivers, it is also feasible to merge both functions into a single device by using an ultrasonic element to switch between sending and receiving signals in a continuous cycle. The transmitter of the module transmits an ultrasonic sound. This sound will be reflected if an object is present in front of the ultrasonic sensor. The reflected sound is received by the receiver present in the same module. An ultrasonic signal is propagated by a wave at an angle of 30°. The above-depicted Figure illustrates how the ultrasonic signal propagates from the transmitter. Measuring angles should be at least 15° for maximum accuracy. In this case, external objects that fall under this measurement angle interfere with determining the distance to the desired object.

 

The distance is determined by measuring the travel time of ultrasonic sound and its speed.

Distance = Time x Speed of sound / 2

Reflection of the sensing sound varies with configuration, for example

 

 

(A) Flat objects: liquid, box, plastic sheet,

(B) Columnar objects: can, bottle, the human body,

(C) Granular objects: ores, rock, coal, coke, plastic pellet,

 

To generate the ultrasonic sound, need to trigger the trigger pin as high for a minimum of 10us. Then the module will start sending 8 sonic burst ultrasounds from the module at 40 Khz. It will receive by the receiver called Echo pin and it will calculate the output time to measure the distance.

 

 

To prevent mutual interference between Ultrasonic Sensors, the synchronous operation can be used by emitting the ultrasonic waves from each Sensor simultaneously.

 

Specifications:

• Supply voltage +5 V;
• Consumption in silent mode 2 mA;
• Consumption at work of 15 mA;
• Measurement range - 2 to 400 cm;
• Effective measuring angle 15°;
• The dimensions are 45×20×15 mm.

How are Ultrasonic Sensors used?

With microcontroller platforms like the Raspberry Pi, ARM, PIC, Arduino, Beagle Board, and many more, our ultrasonic proximity level and distance sensors are often employed. Ultrasonic sensors will send sound waves in the direction of the target and calculate its distance by timing how long it takes for the waves to bounce back to the sensor. In addition, to collision avoidance systems also employ ultrasonic sensors.

 

Here, implemented ultrasonic sensor with Arduino. Before interfacing let us see the pinout of the ultrasonic sensor,

 

Four pins in the ultrasonic sensor

Vcc	power supply +5 V
Gnd	Common ground
Trigger pin	To start the sensor
Eco pin	Receive the signal

Use multiple sensors to avoid interference

When using multiple sensors in an application, it is important to connect them in a way that avoids problems such as crosstalk and other interference. 

 

It is important to keep the front of the ultrasonic transducer clear to avoid interference with the ultrasonic signal from the sensor.

Check out our complete guide on Arduino Interfacing with Ultrasonic Sensor

Advantages of Ultrasonic Sensors

1. Ultrasonic sensors are an excellent way to measure the distance, speed and position of objects. They offer superior accuracy compared to traditional technologies such as lasers or infrared sensors.
2. The ultrasonic wave is generated through a transducer that sends out high-frequency sound waves which travel faster than the speed of light due to their higher frequency range (ultrasonics is in the kilohertz range).
3. These sensors enable manufacturers and engineers for detailed detection over wide ranges with minimal complexity involved when setting up certain systems; they can even detect objects at distances greater than 200m away accurately!
4. Ultrasonic sensors also do not rely on visible light like other types of technology so they can be used indoors/outdoors without worrying about environmental conditions affecting performance levels - this makes them ideal for use in dark areas or lowlight situations where visibility would otherwise be compromised by regular sensing techniques
5. These devices have self-diagnostics capabilities allowing users quick access to system status by checking errors & fault codes and reading back calibration parameters, thus providing easy maintenance routines.
6. With no external power source needed, these types of tools operate more reliably with less downtime thus leading to improved productivity levels across applications relying heavily on its usage ranging from robotics automation industrial monitoring security surveillance activities etc,.

Applications of Ultrasonic Sensor

Ultrasonic Anemometers:

Anemometers are often used in weather stations because they efficiently detect wind speed and direction. 2D anemometers can only measure the horizontal component of wind speed and direction, while 3D anemometers can also measure the vertical component of wind. 

 

Ultrasonic anemometers can not only measure wind speed and direction, but also temperature. This is because the ultrasonic velocity is affected by temperature changes independently of pressure changes. Temperature is calculated by measuring the ultrasonic velocity change.

Tide gauge:

It is used to monitor sea levels and detects tides, storm surges, tsunamis, swells and other coastal processes. Tide gauges can detect water levels in real-time using ultrasonic sensors. Meters are often linked to an online database where records are kept, and the system can trigger alarms if dangerous situations occur.

Tank level:

Measuring the liquid level in a tank is like a level meter. However, in this case, the fluid may be freshwater, corrosive chemicals, or flammable fluids. In contrast to optical sensors and float switches, ultrasonic sensors are not in contact with liquids, which means less corrosion.

Web-guiding systems:

The purpose is to make sure the material is placed correctly. If the material is misaligned, the system mechanically moves the material back into the machine path. Ultrasonic sensors are well suited for web guiding, as the process requires non-contact, fast and efficient functionality.

UAV navigation:

Unmanned Aerial Vehicles (UAVs) (or drones) typically use ultrasonic sensors to monitor objects in their flight path and the UAV's distance from the ground. By automatically detecting safe distances, aircraft can avoid collisions. In addition, since the flight path changes in an instant, drone collision can be prevented by detecting the distance with ultrasonic waves.

Limitations of Ultrasonic Sensors

1. Ultrasonic sensors have a limited range which makes them less effective when larger distances need to be covered or detected.
2. They are prone to interference from other sources and can provide false readings due to these interferences, including reflections off of non-metallic objects that may not be correctly identified by the sensor’s recognition capabilities.
3. Response times for ultrasonic sensing technology is relatively slow in comparison with some other types of distance measurement equipment such as infrared devices meaning they take longer periods of time before an accurate reading is provided back on screen, making it inconvenient where fast responses are needed immediately upon detection.
4. High-density materials, extreme temperatures and small target surfaces are also unable to detect properly using ultra-sonic sensors since their performance gradually reduces under those conditions leading them to underestimate the actual values being measured within their vicinity environment.

Conclusion

In this blog post, we have learned ultrasonic sensors are an incredibly versatile technology with a wide range of practical applications. Understanding the principles and workings of these sensors can help you better appreciate the immense benefits they offer, from automation and security to medical and scientific research. By leveraging the power of ultrasonic sensors, you can unlock a whole new world of possibilities and take your projects to the next level. So why not explore the exciting world of ultrasonic sensors and see how they can transform your work today?

 

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