From the harshest, most extreme weather conditions to the calmest, most predictable conditions, wind measurement can be a critical (if not the most critical) data collected to study and predict weather patterns. Wind data is used across a wide array of industries, including aviation, marine, alpine, agriculture, urban, research, and more. In order to collect useful data, you must first decide which instrument is right for your application. There are two main types of wind sensors: ultrasonic and mechanical. This blog will delve into the advantages and disadvantages of each.

Ultrasonic Wind Sensors

How Ultrasonic Wind Sensors Work:

Ultrasonic wind sensors, like the ResponseONE™ Ultrasonic Anemometer, operate using sound waves. They measure the time it takes for an ultrasonic pulse to travel from one transducer to another. By calculating the time difference caused by wind passing between transducers, the sensor can accurately determine the wind’s velocity and direction.

An ultrasonic wind sensor is made up of 3 main components: the transducers, the processor, and the housing. Typically, there are multiple transducers (usually three or four) arranged in a geometric pattern, such as a triangle or square. Each transducer acts as both a transmitter and a receiver of ultrasonic pulses. The pulses travel through the air from one transducer to another, and the time it takes for the pulse to travel from the transmitter to the receiver is recorded. This time is influenced by the wind speed and direction: when the wind blows in the direction of the pulse, time is reduced. When it blows the opposite direction, time is increased. The processor uses these time differences to calculate the wind speed and direction, then outputs that data to a display unit, data logger, or another system.

Advantages:

• High Accuracy and Precision: Ultrasonic sensors offer high accuracy and precision due to their advanced technology. They can measure even the slightest changes in wind speed and direction.
• No Moving Parts: Since they have no moving parts, ultrasonic sensors are less prone to wear and tear.
• Rapid Response Time: Ultrasonic sensors can provide real-time data with minimal delay, making them ideal for applications requiring instant feedback.
• All-Weather Operation: These sensors perform well in various weather conditions, including extreme temperatures, high humidity, and precipitation. With optional heaters installed, they can withstand frigid temperatures as well.

Disadvantages:

• Higher Cost: The sophisticated technology in some ultrasonic sensors can make them more expensive upfront compared to mechanical anemometers.
• Power Consumption: Ultrasonic sensors typically require a continuous power supply, which can be a drawback in remote or power-sensitive installations.
• Susceptibility to Environmental Interference: Although they are designed to work in various weather conditions, ultrasonic sensors can be affected by lightning and power surges, heavy rain, snow, or dust, potentially leading to inaccurate readings.
• Not User Serviceable: When something goes astray in an ultrasonic sensor, the entire device usually must be sent to the factory for servicing and can only be calibrated in a wind tunnel by the manufacturer, resulting in downtime and higher maintenance costs.
• Lower Range: Ultrasonic wind sensors are great at low wind speeds but can lose signal at higher wind speeds

Mechanical Wind Sensors

How Mechanical Wind Sensors Work:

Mechanical wind sensors measure wind speed through the movement of their components. The most common types of mechanical anemometers are 3-cup anemometers and propeller  anemometers. These devices use simple mechanical principles to provide reliable wind measurements.

As the wind blows, it pushes either the propeller or the cups, causing them to rotate around the shaft. They’re designed to ensure that the cup wheel or propeller is always facing the wind, creating continuous rotation. The speed of the shaft’s rotation is directly related to the wind speed. A magnetic sensor or optical encoder converts the cup wheel or propeller rotation into pulses, then that data is sent to a processor that calculates the wind speed based on the number of rotations per unit of time. The  YOUNG Wind Monitor is a popular sensor that combines a propeller anemometer with a wind vane that always aims the propeller into the wind while also measuring wind direction.  When using a 3-cup anemometer, a separate wind vane is needed to capture the direction of the wind.

Advantages

• Accuracy: The Wind Monitor is recognized as one the most accurate wind sensors in the industry to date, which is why it has become the gold standard for many agencies.
• Simplicity and Reliability: Mechanical anemometers are straightforward devices with a long history of reliable use in various applications.
• Much Higher Range: The Wind Monitor can record wind speeds in excess of 200 mph. A preferred choice when measuring extreme events.
• Cost-Effectiveness: They are often less expensive than ultrasonic sensors, making them accessible for many users.
• Low Power Consumption: Mechanical sensors typically require minimal power, so they’re a great choice for remote locations when power sources are limited.
• Ease of Maintenance: Many mechanical anemometers can be easily serviced by the user. Repairs and calibration can often be accomplished without returning to the manufacturer. Users are able to perform their own calibration using an Anemometer Drive and Vane Angle Bench Stand, so there’s no need for a wind tunnel.

Disadvantages

• Wear and Tear: Though the moving parts are susceptible to wear, advancements in both materials and design has greatly extended operating life of mechanical sensors.
• Environmental Sensitivity: Ice, snow, and debris can obstruct moving parts, causing inaccurate readings or sensor failure.
• Higher Starting Speed: Mechanical sensors typically have a higher starting speed when compared to ultrasonic sensors.

Conclusion

Both ultrasonic and mechanical wind sensors are incredibly powerful tools used interchangeably around the globe, but it’s important to select the appropriate one for your application. If you’re looking for rapid response times due to quickly changing or extremely low wind speeds and have the power source to back it up, then an ultrasonic might be right for you. If you’re looking for more of a tried and true, reliable, highly accurate wind sensor, especially in harsh or high-speed conditions, and have limited power resources available, then a mechanical wind sensor is what you need.

Have questions or wondering which sensor would be right for your application? Learn more about our wind sensors, or contact us and we’ll happily answer any questions you may have.