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For most common meteorological variables, a variety of methods exist for measurement. Wind is no exception and given the plethora of available anemometers ranging from mechanical to ultrasonic, it can be difficult to determine which sensor is right for your application. This quick overview will give you the basics to point you in the right direction.

Common Types – 3-cup, Helical, and Ultrasonic

Wind has two components: direction and speed. Instruments that measure wind speed are known as anemometers and are usually paired with a wind vane to simultaneously measure direction. Three of the most common anemometers are:

• Cup – Consists of several (usually 3) small cups connected to a central axis. Wind speed is measured via the speed of rotation.
• Helical (propeller) – Measures wind via rotation of a propeller that must be oriented into the wind. This is typically accomplished by mounting the propeller on the front of a wind vane.
• Ultrasonic – Ultrasonic pulses are used to measure both speed and direction without the need for moving components.

Anemometer Considerations

When deciding which instrument is right for you, consider the following:

• Instrument Specs
  • Behavior and required accuracy
  • Electrical design and output
• Deployment Conditions
  • Ambient weather
  • Access to measurement site
• Budget
  • Up front cost
  • Maintenance

Instrument Specs

Every instrument will have slightly different behavioral characteristics. These include accuracy, minimum wind speed measurement, and instrument response to rapid changes in speed and direction. Cup and helical anemometers tend to have similar characteristics. These mechanical anemometers are both typically less responsive to rapid (< 3s) changes in wind than ultrasonic devices. However, for most general meteorological measurements, mechanical instruments are sufficient and may even be preferable due to increased simplicity of use. An ultrasonic instrument is more commonly used for specialty high frequency measurements related to eddy covariance.

Electrical characteristics also vary across instrument types and manufacturers. Total power requirements will depend on sensor type and processing. Some instruments have built in heaters that minimize icing, but may require temporary periods of very high power draw, which is a burden on remote solar powered stations. Instrument signals can be either analog, such as resistance or frequency, or digital data like Modbus. Digital signals are more resistant to degradation associated with long cables, but processing must take place on the sensor. Processing of the measurement on the sensor may actually be a benefit as it reduces the processing that must take place on the data logger.

Deployment Conditions

The instrument deployment location is also an important consideration. Weather extremes will test even the best instruments, but high quality craftsmanship will go a long way to preventing freezing of any mechanical components, solar degradation, dust intrusion, and corrosion. When located in inaccessible sites such as mountainous environments, robust designs may be required in order to be reliable. Instrument quality varies widely across manufacturers, so review instrument tests if available.

Budget

Finally, consider your budget for both up front cost and maintenance/repairs. High quality ultrasonic sensors are going to cost more up front due to electrical components and data processing. However, high frequency measurements are often not needed in a basic weather station. Some instruments may require costly yearly calibration by the manufacturer.

Dyacon Wind Sensor

So how does the Dyacon Wind Sensor compare? Our WSD-1 is a rugged three cup anemometer coupled with a wind vane. The low-power onboard electronics provide multi-parameter output including real-time gust detection and 0.1 m/s resolution with industrial Modbus output. It has a proven track record with successful multi-year testing in mountainous environments and requires minimal maintenance. Power draw is substantially less (~1/10^th) than that of other sensors with on-board measurement processing. On-board 2 minute and 10 minute averaging of wind measurements simplifies datalogger programming and further reduces system power requirements.

Chris

Staff Hydrologist

Dyacon has provided fully autonomous weather station solutions to our commercial and industrial users for several years now. Nearly all stations have used the embedded cell phone to provide a reliable wireless interface for a Weather Underground connection, data log upload, and remote command and control.

Nevertheless, there are some applications that require a local solution or one that does not have reoccurring costs.

Dyacon Weather Station Display^TM software fits this need.

Weather Station Display, Dark Theme

Designed for readability and ease of use, Dyacon Weather Station Display rings true with a glass-cockpit-like interface. Light and dark themes allow the best option for the lighting conditions.

One of the principle applications for this software is aviation support, such as for NGOs operating in remote regions where cell phone and Internet connectivity are not available. Dyacon weather stations provide advisory data that ground personnel can relay to pilots through voice radio. In many cases, ground support staff may have specialties other than reading weather data so it’s important that they are able to read the weather conditions easily.

Dyacon Weather Station Display^TM settings ensure that users can easily make changes to the units and connection through a simple, intuitive interface.

Weather Station Display, Settings Screen

Dyacon Weather stations may be connected to the computer either through a cable connection or a short-range (300 ft to 1 mile) wireless link.

Watch for additional features as we continue the progress on this practical, simple weather station software. Users that purchase a license will receive updates as they become available.

We strive to make the most practical, professional weather station solutions for our users. Give us a call.

Eugene

All tools are designed with particular constraints in mind. Engineers must balance design priorities such as precision, cost, ease-of-use, application needs, material characteristics, operating environment, manufacturability, serviceability, and so forth. Compact cars and 4×4 trucks are optimized for their intended application and within their own unique design constraints.

A plastic, $40 weather instrument may be just as effective for a specific application as one that costs $25,000.

Professional Weather Station

It isn’t hard to find consumer-grade equipment with the “Professional” moniker. Ink is cheap.

So, what is a “Professional Weather Station?” Anyone that does the job it is intended to do.

Precision Weather Station

Weather station equipment, like any instrument, is only as good as the installation. Research weather stations can produce junk measurements just as effectively as a grocery store instrument. More decimal places does not make better data.

A number of years ago I worked as a camera repair technician. Occasionally, we would be asked to repair or comment on an “exclusive” camera. These, typically German, cameras claimed exotic capabilities or precision construction and were always owned by amateurs.

In contrast, I worked with several professionals that used low-end equipment because they understood where and how a good image was created and the variables involved.

The principle questions affecting the need for precision and accuracy are determined by the application.

• What measurement change will affect actionable decisions?
• Are comparative measurements between stations involved?
• If comparative measurements are used, can installation and equipment differences be controlled and are differences understood?

For example, aviation applications do not make flight changes if there is a 1 degree or 2 degree change in the wind direction. Wind is reported using 2 min or 10 min averages and presented in 10 degree increments. Consequently, selecting a high-end instruments that provide 0.02 degree resolution may be misguided if this is the principle requirement.

In commercial or industrial weather station applications, wind, temperature, humidity, or other measurements are only one input to management decisions. An increase in air temperature of 5 degrees may increase the risk of worker heat stress, but risks inherent to worker extraction, duration of exposure, re-initiation, task completion, process control, and other factors must also be considered along with available mitigation measures.

“Does little Johnny need to where a coat this morning?” does not require 0.01°C accuracy.

Variability of Physical Measurements

Related to precision, users must also recognize the limitations of physical measurements. Turbulent fluids, such as air, open water, and wind have no absolute depth, temperature, or flow rate for the volume of the body. In these cases averages and other statistical or empirical measures may be used to provide a quantitative approximation. Two matched temperature sensors placed several inches apart will read differently.

Air temperature in a mining tunnel may vary by 10 degrees F or more across the tunnel area. Evaporative cooling from seepage will cool one area while radiant heat from a steam line will heat another. Temperature gradients from floor to ceiling may also be significant. If a single point measurement is used, decision-makers must understand the point at which the measurement is taken.

Dyacon Station on Weather Underground

A more pedestrian weather station example would be the effect of nearby structures on wind patterns, temperature, and humidity. The temperature and wind from a roof-top weather station will be dramatically different from one located in an open field nearby.

Data accessibility

Even the best weather station that is properly installed and collects precision data is useless if the data sits in a log file and is not accessible. There are many research weather stations, often funded through government money, that are merely employment vehicles for those that maintain them. Many gigabytes of data is sitting in databases unused.

Weather Station Report – Cell Phone Screen

Getting the data to the end user is critical. Data delivered by cell phone text message, mobile app, or webpage may help return value on the purchase.

Direct connection to automation equipment may also be required. In some cases this may require additional modules, adapters, or accessories.

Know Your Equipment

Collected data may also not be useful if the data users do not know and understand the nature of the equipment behind the measurements, how or where it is installed, how it is maintained, and how the data is delivered.

Some sensors may have limitations that should be considered. A lightning detector may have range, latency, or detection efficiency characteristics that need to be understood by users.

Additionally, comparative measurements from one station to another may be misleading or useless if these issues are not understood.

Total Cost of Ownership

Upfront cost is only one consideration when purchasing equipment. While the purchase budget may be significant, installation cost, data accessibility, system maintenance, and repairs will take a toll.

Some equipment must be installed and maintained by exclusive dealers. This may or may not be appropriate for your application. If current staff will be used, sourcing equipment that is within the skill-level of available technicians is critical.

Equipment that remains unrepaired because no one knows how it works, jeopardizes the investment and operations that depend on it.

A WiFi-connected weather station may lower reoccurring wireless costs when compared to a cell phone station. However, equipment value may be compromised due to limitations on equipment placement options, internal cost or delay in IT support, and interruptions in data accessibility. All of these may add to the “cost” of a weather station.

Summary

When selecting “The Best Weather Station,” keep the purpose in mind. This is typically much more important than comparing sensor specifications.

Consider ancillary costs when making an equipment selection. Installation and maintenance are significant additions.

While you generally get what you pay for, the best weather station is one that meets your cost, installation, and application needs.

We keep a (growing) list of weather station and instrument manufacturers that we think are significant players in the market, from low-end to “research-grade.” If you would like a copy of the list, please let us know. While not exhaustive, it may help you become familiar with the range of options available.

Contact us if you would like some suggestions. We may not be a fit for your application, but we would love to learn about your needs and point you in the right direction.

Eugene
Product Engineer

Build Your Own Anemometer?

Good anemometers can be expensive. Numerous do-it-yourself versions can be found on the Internet and are made with various components from paper cups to PVC pipe fittings. There are even some 3D printed designs that emulate molded or machined anemometers, but are typically very fragile.

The electronics for do-it-yourself weather instrument are often based on hobby boards, such as Raspberry Pi or Arduino. While function for some applications, they may not offer the robust features for commercial applications.

Import Difficulties

Commercial wind sensors can be difficult to import into some countries. The price of the product, shipping, import duties, and other hurdles can greatly increase the total cost. Users must often work through exclusive dealers, which can be good or bad, depending on the dealer. Service and repair parts have similar complications.

Dyacon Solution

Dyacon began a project to address the following issues:

• Reduce purchase price
• Reduce import costs
• Improve serviceability
• Leverage modern technology
• Utilize in-country skills

As an initial step, Dyacon has developed a wind sensor, specifically for 3D printing (additive manufacturing). The innovative concept is mechanically robust, repeatable, easy to assembly, and easy to repair. The sensor has been tested above 31 m/s (70 mph, 112 kph).

The Dyacon 3D printed anemometer concept consists of three classes of components:

1. 3D printable, wind-tunnel validated, mechanical design.
2. Dyacon Hardware kit (Axle, bearings, and assorted screws).
3. Dyacon sensor board.
4. Assembly instructions.

The 3D printed anemometer parts would be produced by the customer or a Dyacon partner in the destination country. The remaining components would be imported as components (or repair) hardware, minimizing the import costs.

Challenges

Let’s not fool ourselves and presume that 3D printing is easy. There is a significant investment in equipment and skills. Fused filament fabrication (FFF) can require significant skill with different settings for part geometries. Layer adhesion, mechanical strength, part shrinkage, print accuracy, and mechanical fit can be unique to each printer, component, and material.

Assembly skill is also required. Not to mention some testing. In other words, if a user wants a single sensor, it may not be a viable option.

Benefits

While this model does not fit all applications, it offers a compelling opportunity for mid-range weather station needs.

• Wind-tunnel tested design
• Skill participation and value added by the customer or distributor
• Mechanical repair parts can be manufactured as needed
• Import costs are minimized
• Robust electronic solution

Call Us

If you would like to participate in this project as a reseller or distributor, please contact us.

3D Printed Wind Sensor, w-Cable

Dyacon weather stations are now compatible with MesoWest, a weather data service developed by the University of Utah with API access through SynopticLabs.

MesoWest is a free weather data portal that is advertisement free. Data is available in graphic and tabular formats. The data may also be downloaded for further research and analysis. The SynopticLabs API allows users to create their own web portals using National Weather Service and personal weather station data.

MesoWest California Weather Stations

MesoWest Stations in California

The Dyacon weather station and Preston, ID airport can be seen at the following link.
Preston, Idaho Airport

MesoWest Chart of Dyacon weather station in Preston, ID