Contents:

1. The working principle of ultrasonic sensor
1.1 How does the ultrasonic sensor work?
1.2 What is the operating frequency of the ultrasonic sensor?
2. Main technical parameters of ultrasonic sensor
3. What fields can ultrasonic sensors be applied to
4. How to install the ultrasonic sensor correctly
5. Ultrasonic sensor common faults and solutions
6. What is the difference between different types of ultrasonic sensors?
7. Ultrasonic sensor FAQ
a. What is the measuring range of the ultrasonic sensor?
b. What factors affect the accuracy of ultrasonic sensors?
c. What are the differences in the performance of ultrasonic sensors in different media?
d. How to integrate ultrasonic sensors into a control system or microcontroller?
e. What is the compatibility of the ultrasonic sensor with Arduino, Raspberry Pi and other platforms?
f. What are the basic steps for programming an ultrasonic sensor?
8. Conclusion

An ultrasonic sensor is an interesting device that sends and receives ultrasonic waves to measure an object's position, distance, or speed. In simple terms, there is one part responsible for sending out ultrasonic pulses, and when these waves meet obstacles, they will reflect back, and then another part will receive these reflected waves. Based on the time it takes the sound to travel, we can calculate how far away the object is from us. This method is particularly useful because it does not require direct contact with the object, making it ideal for situations where you need to keep clean or handle sensitive materials.

The sensor is very practical and affordable, and you can see it in many places. For example, it is used in factories to monitor the location of materials on production lines, as a reversing radar in cars to help drivers stop safely, and it is also used in smart home systems. The most important thing is that ultrasonic sensors work well in dusty places or in poor lighting, even underwater. So, do you know anything about this device? If not, take a closer look with INFINITECH.

1. The working principle of ultrasonic sensor

1.1 How does the ultrasonic sensor work?

The working principle of ultrasonic sensors is actually very simple. It has a component called a transducer, which emits a series of high-frequency sound waves that we can't hear, called ultrasound. These sound waves travel forward through the air and bounce back when they hit an obstacle. At this point, the same transducer or another receiver will pick up these reflected acoustic signals. It was like we were Shouting in the valley and hearing back.

The next step is calculation. The sensor records the time between the transmission of the ultrasonic wave and the reception of the echo. Because the speed at which sound travels is known (about 343 meters per second, under standard conditions), we can use this time and speed to figure out the distance between the sensor and the obstacle. Specifically, multiply the speed of sound by time and divide by 2 to get the distance one way. In this way, whether it is in the dark or in a place with bad sight, the ultrasonic sensor can tell us exactly where the object is. This makes it ideal for tasks that require accurate distance measurement, such as vehicle obstacle avoidance and material positioning in factories.

1.2 What is the operating frequency of the ultrasonic sensor?

Ultrasonic sensors typically operate at frequencies between 20 kilohertz (kHz) and 200 kilohertz, but the range from 30 kHz to 500 kHz is most commonly used. Common operating frequencies include about 40 kHz, because at this frequency, the sensor can provide good distance measurement performance, and the cost is relatively low. Which frequency you choose depends on the needs of your application. Low frequency ultrasounds (such as 30-80 kHz) are more effective for long distance measurements because they have less attenuation in the air and can travel farther. However, their low spatial resolution means that the detection of small objects or details may not be precise enough. In contrast, high-frequency ultrasound (such as a few hundred kHz), although the propagation distance is shorter, provides higher resolution and better accuracy, and is suitable for application scenarios requiring fine measurement.

2. Main technical parameters of ultrasonic sensor

Understanding the main performance parameters of ultrasonic sensors helps users choose the most suitable ultrasonic sensors according to their specific needs. The following are some common technical parameters:

Operating frequency: Usually in kilohertz (kHz) units, the common range is 20 kHz to 500 kHz, the most commonly used is about 40 kHz.

Measurement range: refers to the distance range that the sensor can effectively detect, such as from a few centimeters to a few meters. This parameter depends on the sensor design and application scenario.

Resolution: Represents the smallest distance change that the sensor can distinguish, that is, the smallest distance between the two nearest measurable points that it can distinguish.

Accuracy: refers to the degree of deviation between the actual measured value and the true value, usually expressed in millimeters or percentages.

Blind zone: The area of the closest distance that the sensor cannot accurately measure, due to the need for a certain time interval between the transmitted signal and the received signal to avoid overlapping.

Response time: The time required to complete a complete transmit-receive cycle affects the data update rate of the sensor.

Operating temperature range: The ambient temperature range in which the sensor can operate normally, such as -20°C to +80°C.

Protection level: such as IP (Ingress Protection) level, indicating the ability to protect against solid particles and liquid intrusion, such as IP67 means that it is completely dust-proof and can be immersed in water for a short time.

Power supply voltage: The range of power supply voltage required by the sensor, such as 5V DC, 12V or 24V.

Output type: CAN be analog signal (such as 0-10V, 4-20mA), digital signal (such as TTL, RS-232, RS-485, CAN bus) or switching output.

Power consumption: The power consumption of the sensor in the operating state, usually in watts (W) or milliamps (mA).

Size and weight: The actual physical size of the sensor and its weight, which is especially important for applications where installation space is limited.

3. What fields can ultrasonic sensors be applied to

Ultrasonic sensors are widely used in many fields because of their unique advantages, such as non-contact measurement, strong adaptability and good cost effectiveness.

Here are some of the main application areas:

Industrial automation: In the factory environment, ultrasonic sensors are used for level monitoring, material detection, robot obstacle avoidance, etc. They can help monitor the level of liquid or solid material in the tank and ensure a constant supply of material on the production line.

Automotive industry: In vehicles, ultrasonic sensors are used as part of the astern radar to help drivers stop and reverse safely. They can detect obstacles behind the vehicle and alert the driver with audible or visual signals.

Smart home: Ultrasonic sensors are used in smart home systems to achieve automatic control, such as intelligent lighting, automatic gating, etc. When someone is detected entering the room, it can automatically turn on the lights or adjust the temperature.

Healthcare: In medical imaging, ultrasound is used to create images of the internal structures of the human body, such as ultrasound examinations of fetuses. In addition, ultrasound can also be used to treat musculoskeletal problems in physical therapy.

Security systems: Ultrasonic sensors are capable of sensing motion and are therefore also used as part of an intrusion alarm system to alert when an object enters a predetermined area.

Environmental monitoring: Can be used for underwater exploration, such as depth measurement in oceanographic research or water quality analysis. Similarly, ultrasonic wind speed and direction sensors can be used in weather stations to monitor wind conditions in wind farms.

Agriculture: In precision agriculture, ultrasonic sensors can assist in soil moisture measurement, crop height measurement, and automated control of sprinkler irrigation systems.

Research and education: as a teaching tool to help students understand the basic principles of sound wave propagation; At the same time, it is often used in scientific research for experimental data collection.

4. How to install the ultrasonic sensor correctly

Proper installation of ultrasonic sensors allows them to perform optimally in a variety of applications.

Here are some basic instructional steps and considerations to help you properly install an ultrasonic sensor:

① Choose the right location

Make sure there are no fixed objects or structures in front of the sensor that could interfere with the signal. Ideally, the target surface should be smooth and perpendicular to the axis of the sensor for optimal reflection. If the target surface is tilted or uneven, it may affect the measurement results.

Considering the impact of environmental conditions such as temperature and humidity on the speed of sound, choose a relatively stable place for installation.

② Fixed sensor

Install the sensor firmly in the desired position using appropriate brackets or fixtures to ensure that it does not move due to vibration or other external forces. For some applications, maintaining the sensor level is very important. A level can be used to adjust the Angle of the sensor to ensure that it is in the correct attitude.

③ Adjust the launch Angle

Adjust the pointing Angle of the sensor according to actual needs to ensure that all areas of interest can be covered. If there are multiple ultrasonic sensors working at the same time, pay attention to the relative position between them to prevent signals from interfering with each other.

④ Connection and power supply

Connect the power and data cables correctly according to the manufacturer's instructions. Pay attention to check whether the voltage meets the requirements, and take necessary protective measures (such as fuse) to prevent overload. To reduce electromagnetic interference, ensure that the device is well grounded.

⑤ Testing and debugging

After the installation is complete, a simple functional test is first carried out to confirm that the sensor can work properly. Adjust sensor parameter Settings, such as measurement range and response time, according to specific application scenarios. Continuously observe the performance of the sensor over a period of time and make adjustments and optimizations accordingly if necessary.

Matters needing attention

• During the installation process, carefully read and follow the technical manuals and safety guidelines provided by the manufacturer.

• Regularly check the working status of the sensor and changes in the surrounding environment, and maintain it in time to ensure long-term stable operation.

5. Ultrasonic sensor common faults and solutions

Here are some typical failures and their possible causes:

No signal or weak signal:

Cause: It may be due to power problems, poor connections, sensor damage, or interference in the working environment (such as electromagnetic interference).

Solution: Check whether the power supply is normal, ensure that all the connection lines are firm and not damaged, and eliminate the interference factors of the surrounding environment.

Inaccurate measurement results:

Reasons: poor reflection ability of the target surface, improper installation Angle, multi-path reflection (that is, the echo returns from multiple paths), and sound velocity changes due to temperature changes.

Solution: Adjust the position and Angle of the sensor, select the appropriate measurement target, consider temperature compensation, and minimize the impact of multipath reflection.

False alarms or frequent alarms:

The reason: there are small objects in front of the sensor that are constantly moving (such as insects), or the sensor is too sensitive.

Workaround: Clean the area around the sensor, adjust the sensitivity Settings, or add filtering algorithms to reduce false positives.

Long response time:

Causes: The internal processing speed of the sensor is slow, the software configuration is faulty, and the communication is delayed.

Solution: Optimize the configuration parameters of the sensor, update the firmware to the latest version, and check whether the communication line is smooth.

Poor long-term stability:

Causes: sensor aging, large changes in environmental conditions (such as temperature and humidity fluctuations), mechanical vibration, etc.

Solution: Perform regular maintenance, replace the aging parts, and improve the installation position to reduce the impact of the external environment.

Physical damage:

Cause: External impact, flooding or other forms of physical damage.

Solution: If physical damage is found, a new sensor needs to be replaced promptly and measures taken to protect the sensor from future damage.

Electrical failure:

Cause: Circuit board fault, wiring error or poor contact.

Solution: Check the circuit board for burn marks or other obvious signs of damage, recheck and make sure all wires are properly connected and secured.

In order to prevent and quickly diagnose these problems, it is recommended to perform regular maintenance checks on the ultrasonic sensor and record the results of each check. At the same time, maintain a good working environment, avoid extreme temperature, humidity is too high or too low and strong electromagnetic interference, can effectively extend the service life of the sensor and improve its reliability.

6. What is the difference between different types of ultrasonic sensors?

Different types of ultrasonic sensors have their own characteristics according to their different designs, working principles and application occasions. Here are several common ultrasonic sensor types and their main differences:

Classification by frequency

• Low-frequency ultrasonic sensors (e.g. 20 Khz-80 kHz) :

  • Advantages: Long propagation distance, strong penetration ability.

  • Disadvantages: Low resolution, less accurate detection of small objects or details.

  • Application scenario: Long distance measurement, such as large storage tank level monitoring.

• High-frequency ultrasonic sensors (e.g. a few hundred kHz to a few MHz) :

  • Advantages: High resolution, ability to detect smaller objects and provide finer distance information.

  • Disadvantages: short propagation distance, easy to be affected by air humidity and temperature.

  • Application scenarios: Precision measurement, such as medical imaging, small object detection, etc.

Sorted by shape and structure

• Drip proof type:

  • Features: Usually has a metal shell sealing structure, suitable for outdoor or wet environment use.

  • Application scenarios: vehicle use, outdoor industrial equipment, etc.

• Open (lead type/patch type) :

  • Features: There is no completely closed shell, which may be more susceptible to external factors.

  • Application scenario: Internal installation, non-harsh environment application.

• Cylindrical/square:

  • Features: Various shapes, easy to install in different positions.

  • Application scenarios: various industrial automation equipment, household appliances, etc.

Classification by function

• Ranging sensor:

  • Features: Mainly used to measure the distance between the object and the sensor.

  • Application scenarios: reversing radar, automatic door, robot navigation, etc.

• Liquid level sensor:

  • Features: Specially used to measure the horizontal height of liquid or solid materials.

  • Application scenarios: Storage tank level monitoring in water treatment, chemical plants, food processing and other fields.

• Flow meter:

  • Features: The use of ultrasonic technology to measure the flow rate and flow of fluid.

  • Application scenario: Measurement of liquid or gas flow in pipelines.

• Wind speed sensor:

  • Features: Wind speed is calculated by measuring the time difference of ultrasonic wave propagation in the air.

  • Application scenarios: weather stations, wind farms, etc.

Classification by working principle

• Piezoelectric type:

  • Features: Based on the piezoelectric effect of piezoelectric materials, it can transmit and receive ultrasonic waves.

  • Application scenario: Widely used in all kinds of ultrasonic sensors.

• Magnetostrictive type:

  • Features: The use of magnetostrictive materials under the action of magnetic field deformation characteristics.

  • Application scenario: Specific industrial measuring equipment.

• Electromagnetic type:

  • Features: Ultrasonic wave is generated by electromagnetic vibration.

  • Application scenario: Ultrasonic generator in some special occasions.

The selection needs to be based on the specific application requirements to determine the most suitable type.

7. Ultrasonic sensor FAQ

a. What is the measuring range of the ultrasonic sensor?

The measurement range of ultrasonic sensors can range from a few centimeters to tens of meters, depending on the design and specifications of the sensor. Common measurement ranges include: short distance: a few centimeters to one or two meters, suitable for close detection, such as automatic doors in smart homes or robot obstacle avoidance. Medium distance: one or two meters to ten meters, suitable for general industrial automation, liquid level monitoring, etc. Long distance: tens of meters to tens of meters, suitable for the level monitoring of large storage tanks or outdoor applications.

b. What factors affect the accuracy of ultrasonic sensors?

The accuracy of ultrasonic sensors can be affected by a variety of factors, including changes in temperature and humidity, the characteristics of the target surface, multipath reflection, noise interference, the choice of installation location, the stability of the power supply, and the aging and wear of the equipment over time. These factors may affect the measurement accuracy of ultrasonic sensors.

c. What are the differences in the performance of ultrasonic sensors in different media?

In air, ultrasonic waves travel relatively slowly (about 343 m/s, at 20°C) and change with temperature.

In liquids, ultrasonic waves travel faster (for example, about 1,480 m/s in water). Due to the high density of the liquid, the ultrasonic attenuation is small, so it can be used for more distant measurements.

In solids, ultrasound travels fastest, but has few practical applications, except in specific non-destructive testing situations.

d. How to integrate ultrasonic sensors into a control system or microcontroller?

Hardware connection: Usually, the ultrasonic sensor will have VCC (positive power supply), GND (ground), Trig (trigger) and Echo (echo) four pins. Connect the VCC to the microcontroller's power output, GND ground. The Trig and Echo are connected to the digital I/O ports of the microcontroller, respectively.

Software programming: Initialize the GPIO pin. The Trig pin is triggered to send a short, high level pulse to initiate the ultrasonic emission. Monitor the response time of the Echo pin to calculate distance.

e. What is the compatibility of the ultrasonic sensor with Arduino, Raspberry Pi and other platforms?

Arduino: Very compatible, there are many off-the-shelf libraries (such as the NewPing library) that can help quickly implement the functions of the ultrasonic sensor.

Raspberry Pi: Also supports the use of the GPIO interface to control ultrasonic sensors, which can be coded in Python or other languages.

f. What are the basic steps for programming an ultrasonic sensor?

① Initialize GPIO：

Set the Trig pin to output mode.

Set the Echo pin to input mode.

② Trigger ultrasonic emission:

Give the Trig pin a short high level pulse (usually 10 microseconds).

③ Wait and measure the echo:

The timing starts when the Echo pin becomes high.

Stop timing when the Echo pin returns to low power level.

Calculate how long the high level lasts.

④ Calculation distance:

Use the formula Distance=(Time x Speed of Sound)/2 to calculate distance.

Where, Time is the time difference between sending a signal and receiving an echo, and Speed of Sound is the speed of sound.

⑤ Processing data:

Data is filtered and smoothed as needed to improve stability.

8. Conclusion

Ultrasonic sensors, with their non-contact measurement, extensive adaptability and cost-effectiveness, play an indispensable role in many high-tech applications and greatly promote the innovation and development of various industries. Through the above introduction, I believe you have a preliminary understanding of ultrasonic sensors; If you have any further questions or need further discussion, please feel free to leave a message.