What Is An Ultrasonic Sensor? Working Principle, Applications (Quick Guide)

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Ultrasonic sensors have been used for decades. It is still used to capture a large market share due to its various capabilities, flexibility, and low cost.

With the advancement of technology and the invention of new products, the demand for ultrasonic sensors is increasing. Ultrasonic sensors are used in robots, autonomous vehicles, and drones. Let us understand how ultrasonic sensors work and what their applications are.

What Is An Ultrasonic Sensor?

Ultrasonic sensors help in measuring the distance of an object using ultrasonic waves. It works by measuring the time between emission and reception. Using an ultrasonic sensor requires a transducer that sends and receives ultrasonic pulses from the object.

A distinct echo pattern is produced by high-frequency sound waves reflecting off each other.

How Do Ultrasonic Sensors Work?

Ultrasonic sensors use ultrasonic waves to detect the distance between two objects. An ultrasonic sensor converts the reflected sound into an electrical signal.

This principle uses ultrasonic waves to measure the distance between a target and an object. An ultrasonic sensor consists of two components: a transmitter and a receiver.

A transmitter that generates sound waves via piezoelectric and transmits ultrasonic sound waves. Sound is reflected only if the object is placed close to the ultrasonic sensor. On the other hand, the receiver detects the reflected ultrasonic sound waves.

Some sensors emit and receive sound in different ways. In that case, an ultrasonic element can be used to combine the two functions in one device.

When ultrasonic sound waves hit an object, they bounce back to the module. A receiver in the module picks up these bounce waves. By measuring the time it takes for the waves to travel back, the sensor can find out how far away the object is. This type of sensor is often used to measure distances, detect obstacles, and provide accurate and reliable information for various applications in many automated systems. Also, you should understand the different types of motion sensors and how they work to choose the right one for your needs as part of a sensor.

Typically, ultrasonic sound waves propagate at an angle of 30 degrees. Externally placed objects fall under a measurement angle that interferes with measuring the distance to the desired object. For maximum accuracy, the measurement angle is 15 degrees.

An example of how an ultrasonic sensor works:

Suppose you want to design a project for a parking system. To find a parked car, you must include a sensor. Ultrasonic sensors have been placed at each parking spot. It helps the car pass through a series of ultrasonic sensors.

Ultrasonic sensors help vehicles emit high-frequency sound waves. This wave reflects off the car as an echo of the transducer. A transducer acts as both a sender and a receiver.

This allows the ultrasonic sensor to calculate how long it takes the vehicle to travel back and forth.

How Ultrasonic Sensors Are Used?

After the ultrasonic sensor sends sound waves to the target, the distance is calculated. Distance is calculated based on how long it takes for the waves to bounce back. In the case of collision-avoidance systems, ultrasonic sensors are also used.

Applications Of Ultrasonic Sensors

Ultrasonic sensors are used in various fields of engineering automation, robotics, and instrumentation, they are also useful in distance measurement and are used.

1. Tide Gauge

To monitor sea level, tide gauges are used. Tide gauges work using ultrasonic sensors that help detect water levels, tides, storms, tsunamis, and swells.

2. Ultrasonic Anemometers

Ultrasonic anemometers are used in weather stations. It can detect wind speed and direction effectively. A 2D anemometer measures the horizontal component of wind speed and direction. A 3D anemometer measures wind speed and direction vertically.

It is very useful for measuring temperature. The temperature is calculated by measuring the speed in the ultrasonic sensor.

3. Tank Level

The tank level is approximately the same as the tide gauge. Ultrasonic sensors help prevent corrosion of tank surfaces because they are not exposed to liquids.

4. Functional In Sunlight

Most sunlight is made up of infrared light. Infrared light present in sunlight can sense objects. Ultrasonic sensors are not affected by the infrared rays of sunlight.

5. Web-Guiding Systems

Web-guiding systems widely use ultrasonic sensors. It has flat material. Web-guiding systems use ultrasonic sensors to detect and track objects. With the help of this ultrasonic sensor, the guidance system can place the objects correctly. Ultrasonic sensors are ideal because web-guidance systems require non-contact, high-speed, and efficient operation.

6. UAV Navigation

UAVs (Uncrewed Aerial Vehicles) use ultrasonic sensors to detect objects in their path.

UAV navigation seeks a safe distance to avoid crashing. If the flight changes its direction, ultrasonic sensors detect the distance and help them position themselves correctly.

Limitations Of Ultrasonic Sensors

1. Atmospheric Movements

Atmospheric movement can disrupt the performance of ultrasonic sensors. Moving air interferes with the measurement and limits the range. This unnecessary noise can create detection errors.

2. Precision In Detecting Temperature Changes

Temperature can play an important role in how ultrasonic sensors work. Models with temperature compensation will avoid the problem.

3. Sound-Absorbing Material Cannot Be Detected

Sound-absorbing materials such as sponges, foams, and soft fabrics are hard to find. Ultrasonic sensors are disrupted due to their ability to absorb most of the reflected ultrasonic energy.

Advantages Of Ultrasonic Sensors

Ultrasonic sensors are excellent tools for measuring the distance, speed, and position of objects. They have several advantages that make them superior to other technologies such as laser or infrared sensors.

High Accuracy:

  • Ultrasonic sensors provide more accurate measurements compared to lasers or infrared sensors.
  • They can detect objects accurately even at a distance of more than 200 meters.


  • This sensor works by emitting high-frequency sound waves through a transducer.
  • Sound waves travel faster than light due to their high frequency (in the kilohertz range).


  • They can be used both indoors and outdoors without worrying about lighting conditions.
  • Ideal for dark or low-light areas where other sensors may fail.

Easy Setup:

  • Ultrasonic sensors are easy to set up and do not require complicated procedures.
  • They offer a wide range of detailed searches with minimal complexity.


  • Ultrasonic sensors have built-in self-diagnosis capabilities.
  • Users can quickly check system status, error codes, and calibration parameters.
  • This makes maintenance easy and efficient.

No External Power Source Is Required:

  • This sensor works without the need for an external power source.
  • They are more reliable and have less downtime, leading to improved productivity.

A Wide Range Of Applications:

Ultrasonic sensors are used in many fields such as:

  • Robotics
  • Industrial Automation
  • Monitoring Systems
  • Security and Surveillance

Ultrasonic sensors are highly accurate, versatile, and easy to set up and maintain. They perform well in a variety of environments and applications, making them a valuable tool for many industries.

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