How to choose between mechanical and ultrasonic wind speed and direction sensors?
In the natural environment, wind speed and direction are important meteorological factors in environmental monitoring. Wind affects our lives all the time. In modern society, with the advancement of science and technology, wind speed and direction sensors used to monitor the direction and size of wind are becoming more and more popular. It has been widely used in meteorology.
There are currently two types of equipment used to monitor wind speed and wind direction: one is a wind speed and wind direction sensor with a mechanical structure, and the other is a wind speed and wind direction sensor that uses ultrasonic measurement; these two sensors are two common devices in daily life , what are the similarities and differences between the two, whether there are accuracy issues, and how to choose. Let's listen to the editor explain in detail:
First of all, let's talk about the mechanical wind speed and wind direction sensor. The mechanical wind speed and wind direction sensor is not a whole, and is divided into wind speed sensor and wind direction sensor:
wind speed sensor
The wind speed sensor with mechanical structure is a sensor that can continuously measure wind speed and air volume (wind volume = wind speed × cross-sectional area). The more common wind speed sensor is the wind cup type wind speed sensor. It is said that this sensor was first invented by Robinson Crusoe in England. The measurement part is composed of three or four hemispherical wind cups. The wind cups are installed on a rotating bracket vertical to the ground at equal angles in one direction.
wind direction sensor
The wind direction sensor uses the rotation of the wind direction arrow to detect and sense the external wind direction information, and transmits it to the coaxial code plate, and at the same time outputs a physical device corresponding to the wind direction related values; its main body adopts the mechanical structure of a wind vane. When the wind blows toward the wind vane, When the wind vane is on the tail, the arrow of the wind vane will point in the direction of the wind. In order to maintain sensitivity to direction, different internal mechanisms are also used to identify the direction of the wind speed sensor.
Ultrasonic wind speed and direction sensor
The working principle of ultrasonic waves is to use the ultrasonic time difference method to measure wind speed and direction. Because the speed of sound propagating in the air will superimpose with the speed of the airflow in the wind direction. If the ultrasonic wave propagates in the same direction as the wind, its speed will increase; conversely, if the ultrasonic wave propagates in the opposite direction to the wind, its speed will slow down. Therefore, under fixed detection conditions, the speed of ultrasonic waves propagating in the air can correspond to the wind speed function. Accurate wind speed and direction can be obtained through calculation. Since sound waves propagate in the air, their speed is greatly affected by temperature; the wind speed sensor detects two opposite directions on two channels, so the effect of temperature on the speed of sound waves is negligible.
To sum up, since the wind direction sensor and wind speed sensor are both mechanically designed and have rotating parts, the minimum wind speed is the starting condition before monitoring. If the wind speed is lower than the starting value, the propeller or wind cup will not be driven to rotate. Therefore monitoring is not possible. In contrast, there is the ultrasonic wind speed and direction sensor. The biggest feature of this device is that it can work even at zero wind speed without starting the wind speed. And unlike the mechanical wind speed and direction sensor, which requires two devices, the ultrasonic sensor combines two The two monitoring methods are integrated into one, detecting and outputting at the same time.
With the rapid development of the Internet of Things, there is an increasing demand for the accuracy of monitoring meteorological elements. The use of ultrasonic wind speed and direction sensors can well overcome the inherent shortcomings of mechanical wind speed and direction sensors, so they can work normally all day and for a long time. If If the cost can be reduced in the future, it will be a powerful alternative to mechanical anemometers.
