Ultrasonic distance measurement, ultrasonic ranging formula

Transmissive: l = c t

Reflective: l=1 2c t

l is the measurement distance; c is the propagation velocity of ultrasound; The time of propagation of t (t is the time of transmission to reception of the messenger).

<> ultrasonic ranging is a one-way measurement, the sender node initiates a ranging slag call by broadcasting a packet, and establishes a time while sending the packet. Due to the strong directivity of ultrasonic, slow energy consumption, and the distance from Chizhou in the medium, ultrasonic is often used for distance measurement, such as rangefinder and level measuring instrument, etc., which can be achieved by ultrasonic. The use of ultrasonic detection is relatively fast, convenient, simple to calculate, easy to achieve real-time control, and can meet the requirements of industrial practicality in terms of measurement accuracy, so it has also been widely used in the development of mobile robots.

In order for the mobile robot to automatically walk to avoid obstacles, it is necessary to equip a ranging system to obtain the distance information from the obstacle in time.

Summary. Ultrasonic ranging is a technique that uses the travel time of ultrasonic waves to measure distance. In ultrasonic ranging, ultrasonic waves are emitted to the target object, and after the ultrasonic waves return, the distance between the target object and the sensor can be calculated by measuring the time difference between the sent and received ultrasonic waves.

And why divide by 200? This is because the speed of sound travels in the air at a speed of about 340 meters, that is, sound waves can travel a distance of 340 meters in 1 second. In practical applications, ultrasonic waves of tens or hundreds of kilohertz are usually used, with high frequency and short wavelength, so the attenuation during propagation is large.

Therefore, in order to calculate a more accurate distance, it is necessary to divide the measurement by 200, i.e. 340 meter seconds divided by 2 times the frequency (in hertz) to obtain a more accurate distance value.

Ultrasonic ranging is a technique that uses the travel time of ultrasonic waves to measure distance. In ultrasonic wax splitting wave ranging, ultrasonic waves will be emitted to the target object, and after the ultrasonic wave returns, the distance between the target object and the sensor can be calculated by measuring the time difference between the sent and received ultrasonic waves. And why divide by 200?

This is because the speed of sound travels in the air at a speed of about 340 meters, that is, sound waves can travel a distance of 340 meters in 1 second. In practical applications, ultrasonic waves of tens or hundreds of kilohertz are usually used, with high frequency and short wavelength, so the attenuation during propagation is large. Therefore, in order to calculate a more accurate distance, it is necessary to divide the measurement by 200, i.e. 340 meter seconds divided by 2 times the frequency (in Helun Nians), so as to obtain a more accurate distance value.

Can you add, I don't quite understand it.

Ultrasonic ranging is a common non-contact ranging technology that uses the properties of ultrasonic waves to measure the distance between an object and a sensor. Ultrasound is a mechanical wave with a frequency higher than the hearing range of the human faith and travels at a speed of about 340 meters and seconds in the air. The basic principles of ultrasonic ranging are:

The transmitter sends ultrasonic signals to the object being measured, and when these signals hit the object and return to the receiver, the rangefinder calculates the round-trip time of these signals and converts them into distances. Ultrasonic ranging technology is widely used in industrial automation, robot navigation, vehicle slide reversing radar, medical imaging and other fields. In the industrial field, ultrasonic ranging can achieve accurate measurement and position control of objects, especially in harsh environments such as high temperature, high pressure, high humidity, etc., ultrasonic measurement technology still has excellent stability and reliability.

In the medical field, ultrasound imaging can visualize the internal organs of the human body, which can be used to diagnose diseases and guide surgery.

The minimum pore size that can be measured by ultrasonic waves is the smallest size, but in actual measurement, due to the propagation characteristics of ultrasonic waves, sometimes the results of the measurement are inaccurate. The methods and practical steps to solve this problem are as follows:1

First, the pore size of the ultrasonic measurement is determined, as well as the distance to be measured, so that the ultrasonic wave propagation path can be determined. 2.Secondly, it is necessary to determine the emission frequency of the ultrasonic wave, as well as the emission power, so as to determine the propagation distance of the ultrasonic wave.

3.Then, the frequency at which the ultrasonic waves are received, as well as the receiving power, are determined in order to determine the distance at which the ultrasonic waves are received. 4.

Finally, the propagation time of the ultrasonic wave is determined, as well as the propagation distance, so as to determine the propagation effect of the ultrasonic wave. The above is the method and practice steps to solve the inaccurate pore size of ultrasonic measurement, in practical application, it is necessary to complete according to the actual situation, combined with relevant knowledge and comprehensive consideration, in order to obtain accurate measurement results.

If the system is a barrel and you don't have enough water in it, it's actually short for each plank, not two pieces.

From what you've described, the biggest bottlenecks right now are drive voltages and probes. The transmission voltage is increased to 50-150VP-P, and the open probe is used, which should be able to measure about 5 meters.

If you want to measure 11 meters, I don't know what period you want to measure, once every 1 second? 10 times in 1 second? 1 time in 10 seconds?

1. If the ranging period is longer, the transmission voltage can be further increased, which should reach 200 800VP-P (depending on the probe), it is recommended to use a pulse transformer, and the drive can not use 74HC04, replace it with a switch tube, and the instantaneous current is estimated to be between 1A-30A. The advantage of a long cycle time is that you are not afraid of test failure, you can perform multiple tests in a test cycle, and the final test result is only the one time you succeed in the test.

2. If the ranging period is short, it is generally required to have a high success rate for each detection, and in the face of different environments and measured objects, the ranging system has higher requirements for the receiving circuit. On the premise of satisfying 1, the receiving circuit should also be improved, and the noise peak level should be lower than 1VP-P in the case of amplification of 10,000-1 million times, and 20106 may be difficult to compete;

3. If it needs to be used outdoors, under the premise of satisfying the first two items, a waterproof probe should be used, and an ultrasonic probe with a diameter of more than 50mm is required for a detection distance of 11 meters;

4. If you still need all-weather high-reliability operation, or if you want high sensitivity, you need to sacrifice some ranging accuracy and reduce the ultrasonic emission frequency from 40kHz to 25kHz 32kHz to reduce air loss.

Mine is 5V voltage, can only measure 50cm, I want to ask the landlord how to improve, thank you!

Hello, I have the same problem as you, has your problem been solved? Hope to get in touch with you.

The formula for ranging is expressed as: l=c t

where l is the length of the distance to be measured; c is the propagation speed of ultrasonic waves in the air; t is the time difference between the measured distance propagation (t is half of the value of the transmit to receive time).

l = c*t；l = distance, c is the speed of sound, and t is time.

c = sqrt: open root number. t is Celsius.

Transmissive: l = c t

Reflective: l=1 2c t

l is the measurement distance; c is the propagation speed of ultrasound; The time of propagation (t is the time from transmit to receive).