Anémomètre à ultrasons

L’ultrasonic anemometer is a modern, precise, and reliable sensor. It allows measuring wind speed and direction without mechanical inertia. The measurements obtained are instantaneous and very accurate.

Operation of the ultrasonic anemometer

Unlike mechanical cup anemometers that measure wind speed mechanically, the ultrasonic anemometer calculates wind speed by measuring the travel time of an ultrasonic wave. The device consists of an emitter and a receiver (electroacoustic transducers) that communicate through an ultrasonic signal along an orthogonal axis. They are placed at a known distance, allowing the calculation of the propagation time of the ultrasonic wave. Depending on the wind speed, the wave travels faster or slower, enabling the deduction of wind speed.

A large distance between the probes allows for better accuracy. However, to maintain small-sized sensors, manufacturers employ a technique that reflects the wave.

For wind direction, the principle is similar. This time, four ultrasonic sensors are used to determine wind direction based on wave propagation.

Wind measurement by ultrasound is precise and reliable, which is why ultrasonic sensors are widely used in the professional field to manage land and offshore wind farms.

Advantages of ultrasonic anemometers

Ultrasonic technology has several advantages.

• No mechanical parts
• Reduced footprint
• Mobility and adaptability

Compared to a wind vane anemometer, it does not contain sensitive mechanical parts subject to wear or breakage (cups, blades) and requires less maintenance. Therefore, its lifespan is longer and it can withstand more adverse weather conditions.
It should also be noted that the ultrasonic anemometer offers superior measurement quality, especially in cases of strong wind gusts. A cup anemometer relies on mechanics to obtain a measurement, which does not allow it to achieve very precise measurements during gusts.

Given that the sensors are small, this type of anemometer takes up little space. It can be combined with other sensors to create a complete weather station. It can be installed permanently or serve as a mobile weather station.

Example: pairing an ultrasonic anemometer with a GPS and a compass allows for determining wind speed and direction while being mobile.

Weak points

The ultrasonic anemometer is aimed at an informed audience, individuals with specific needs, or professionals. Consequently, there are few models available, and the cost of these devices remains higher than that of classic models.

Netatmo NWA01-WW: an anemometer that stands out

The Netatmo weather station allows pairing with several accessories, including the anemometer presented below, the Netatmo NWA01-WW.

It is an ultrasonic anemometer to be placed on the roof or a 10-meter mast to obtain precise and reliable measurements.

The Netatmo ultrasonic anemometer is equipped with four ultrasonic transducers capable of recording wind speeds ranging from 0 to 45 meters per second with an accuracy of 0.5 m/s. It will also indicate the wind direction with an accuracy of 5°.

Capable of measuring low wind speeds and strong rapid gusts, the Netatmo NWA01-WW anemometer provides very precise data.

Despite its small size, the Netatmo NWA01-WW is a quality device, robust and reliable over time. The plastic used is designed to offer high resistance to weather-related factors: sun exposure, rain, hail, and wind gusts.

The device is easy to install and does not require an external power source. It operates with 4 AA batteries and transmits data via a wireless connection to the Netatmo smart weather station (sold separately). Data can also be transmitted to a smartphone (iOS, Android, Windows Phone). This makes it possible to access information at any time or receive alerts in case of strong winds.

When combined with a home automation center, it allows for shutting windows or stopping automatic watering in the case of strong wind gusts.

It is also possible to associate it with a rain gauge to obtain precipitation data.

Summary

• 4 ultrasonic transducers (reliable and precise measurements)
• High-quality plastic (weather resistance)
• Height 10 meters
• Diameter 8.5 cm (compact size)
• Measurement range: 0 to 45 m/s or 0 to 160 km/h
• Accuracy: +/- 0.5 m/s
• Wind direction: accuracy +/- 5°
• Power supply 4 AA batteries included
• Wireless connection compatible with iOS 7+, Android 4.0+, Windows Phone 8.0+, or computer
• Range 100 meters
• Recommended installation height 12 meters without obstacles
• Works with the Netatmo smart weather station (sold separately)

Assets

• High-performance anemometer
• Neat and modern design
• Quick installation
• High precision of collected data

Weak points

• Requires the Netatmo weather station to operate

Our opinion on the Netatmo NWA01-WW

The anemometer offered by Netatmo is an excellent product with a sleek and discreet design. It will suit many architectures.

The ultrasonic technology, in terms of measurements, works wonderfully well. With remarkable accuracy, it is significantly superior to wind vane anemometers. Data is transmitted directly to the Netatmo smart weather station. This aspect can be perceived negatively as the product’s compatibility is limited to this specific weather station; however, fortunate owners of a Netatmo station will be pleased to have a « ready-to-use » device with fast and simple connectivity.

It should also be noted that the support for the Netatmo NWA01-WW anemometer is sold separately. This is very useful for those who already have a support for anemometers; however, for others, it must be added to your order.

Netatmo NWA01-WW is a product we recommend if you plan to install a Netatmo weather station at your home or if you already own one. This ultrasonic anemometer will provide excellent data on the wind blowing around your house.

Complementary Netatmo products

Mount for Netatmo NWAM01-WW anemometer

This mount secures your anemometer to a mast or gutter.

Connected rain gauge Netatmo

The rain gauge associated with the anemometer will provide you with a more complete set of data for better monitoring and weather forecasting.

Ultrasonic wind sensor: speed and direction

This integrated wind sensor allows for evaluating wind speed and direction thanks to its 4-20MA type ultrasonic probes.

Made from rigid plastic, monobloc, the anemometer is resistant to wear, ensuring a long lifespan and requiring no maintenance.

Its lightweight and sleek design allows for easy integration into different types of architecture. It is easy to install and disassemble if necessary.

Ultrasonic sensors provide reliable and stable measurements even in strong wind conditions.

The ultrasonic anemometer can perform high measurements, without speed limits, at all angles (360 °C) and simultaneously provides speed and direction data.

Not sensitive to inertia, the acoustic phase compensation technology ensures very high precision and fast response.

Installation is done via the 4 fixing holes located around the circumference of the frame. The anemometer must be securely fixed to the support using bolts to ensure the precision of the collected data.

During installation, the letter N located at the top of the device must be oriented towards the north using a compass to minimize precision errors as much as possible. Incorrect installation of the sensor will distort the collected data and their analysis.

The sensor must be connected to a weather station to collect data.

Other models of ultrasonic sensors

There are a few other models of ultrasonic anemometers, but their price is high compared to those offered above.

With a minimum of knowledge in electronics and a bit of enthusiasm, it is possible to build your own ultrasonic anemometer by purchasing ultrasonic sensors. Here is a selection of available sensors: