Etesian Breeze Bluetooth at the Green River Festival

Every year in mid July the now famous Green River Festival was happening and celebrating it’s 30 anniversary.  Klondike Sound installed one of our Bluetooth based wireless wind anemometers on the far corner of their sound tower.IMG_1834

If you squint you can see it on the back right corner at the top of the  scaffolding.  Turns out it wasn’t very windy, but it’s always good insurance to be prepared.  Turns out it was rainy – not great for the festival, but the area is in the middle of a drought, and we’ll take any rain we can get at this point.  Many towns in Western Massachusetts are in the middle of a water ban.


Etesian Technologies Introduces New Low Cost Self-Powered Wireless Wind Gauge

By leveraging the capabilities of today’s smart phones, Etesian Technologies is pleased to introduce a new Bluetooth ® based self-powered wireless anemometer.  It is the simplest of systems. By downloading an app for your Android or iPhone, your phone becomes the readout for your wireless anemometer sensor.  It can’t do everything our 900 MHz system does.  First, Bluetooth is limited to a range of a little more than 100 meters, about 330 feet.  Also, it would not be applicable for fountain control – there are no output relays on a smartphone and who would want to dedicate their smartphone 24/7 to controlling a fountain anyway!

But for many of our users, requiring the monitoring of wind speeds for crane operations or outdoor staging this new Bluetooth approach should be just fine.  Etesian has chosen to use a Bluetooth technique that allows many simultaneous “listeners”.  No pairing of devices is required.  Each sensor has an ID number, just like our 900 MHz systems.  The ID number is entered in the app’s screen, at which time reception begins.  Not all of our customers are in the US, where the most common unit for measuring wind speeds is mph.  The apps allow the choice of units: mph, knots, m/s and kph.  One last convenient feature is a simulated LED that flashes or stays green, indicating that the smart phone is in range and receiving data.  Did I mention the apps are FREE!  The basic sensor which includes temperature currently lists at $599.bluetooth anem and apps

Fountain Control

Fountain control is one of the major uses for our wireless anemometers.  Turns out that large water features (and some not so large) will lose lots of water, and get people and cars soaked if the wind picks up.  Our wireless wind sensor is ideal. Locate it where it accurately measures the wind and put the receiver down in the vault by the pump controller.  We have two possible options – a voltage signal representative of the wind speed for PLC based pump controls and a simpler wind switch relay which can be set to trigger at a particular wind speed to shut off a pump directly.  We recently provided a system to Greenscape Pump and they were kind enough to send us some photos of installation.  This water feature is located at the Energy Center 3 in Houston. No wires – no batteries – no maintenance.




Measuring Winds in the Smokey Mountains – From the Center of a 200 foot Observation Wheel

There are so many situations that require accurate and reliable measurement of wind speeds.  It’s nice to be surprised at the calls that come in asking for information on Etesian Technologies’ wind measurement gear.  We received an inquiry some time ago from Chance Rides Mfg.  As the conversation progressed I came to understand they were manufacturing and installing a 200 foot tall observation wheel at Pigeon Forge, Tn. It took me a while to figure out that an Observation Wheel is a modern day version of a Ferris Wheel.  This beautiful piece of engineering has 42 climate controlled gondolas.  What I didn’t know is that every gondola had a radio transmitter sending back all kinds of data to the control room.  Information like gondola temperature, door lock status, and other important safety measurements.

Wheel at Pidgeon Forge

42 radios all broadcasting at the same time requires a truly modern and sophisticated radio infrastructure, much like the cell phone network.  It uses a technology called spread spectrum aka frequency hopping.  Here’s a little know fact.  This technology was co-invented by the very famous movie star of the 1940’s, Hedy Lamarr. (

This background of 42 radios blanketing the airspace around the wheel, made it impossible for our standard wireless anemometer to communicate back to our base station and alarm.  We considered building a custom unit to operate at a different frequency, but it turned out, the wheel had a few spare wires already in place, and it was a straightforward job to use one of our more conventional wired sensors to do the job.

Documenting the Storm of January 27

Nor’easters, and storms in general have a much different quality these days.  With modern weather forecasting, we all benefit from the early warnings, allowing us to prepare and hunker down.  And that’s exactly what we did here at Etesian, as did everyone else in the Northeast. Storms being what they are, it gives me the opportunity to showcase our data logger by displaying some data from the day of the storm.

The data logging feature won’t be of any surprise to our wind power customers.  They typically purchase the 201 readout equipped with this option.  Keeping a record of the wind and in some instances the power produced by their wind turbine, allows them to track of the productivity of their wind turbines.  We have a handful of other customers, who for a variety of reasons have wanted the data logging option as well.


 201 with logger option – (USB flash drive plugged in middle bottom)

In brief, the data logger saves a file every day to a USB flash drive.  These files are spreadsheet files, and they open directly in all modern spreadsheet programs (i.e. Excel) , and in many other types of analysis programs that deal with files referred to as “CSV files”.  CSV refers to comma separated values, meaning a bunch of rows and columns of numbers, each number separated from the next with comma, and each line ending with a <CR> carriage return.

Every day the file saved to the USB flash drive is named that day’s date.  So, in our example here, the file on the flash drive is 20150127.csv, as that date was the day of the storm and the most interesting data to look at.  There are several was to put the data on your PC.  Sneakernet is the easiest, if the logger is close by.  Remove the USB flash drive from the logger, insert it in your PC and copy the files.

If your logger is remote, with the appropriate connectivity options, you can download the data with a telnet connection, or, with our newest logger containing a mobile (cell) network modem, the data is pushed to a cloud server every day and can be retrieved from the cloud to your PC.


 Etesian’s newest PV powered cloud connected data logger

Let’s see what the storm looked like here in Western Massachusetts.  First, our facility has a sensor outside measuring wind speed and temperature.  Our logger does not have a precip detector connected to it, although there is no reason you couldn’t have one attached to it.  All I can tell you about our snowfall is that unlike Central Massachusetts which got pummeled with about 3 feet of snow we got a respectable 10 inches, but nothing spectacular.

Our logger is next to my desk, so I copied the file on the USB drive to my PC and made a few plots of wind speed and direction.  Just for fun, I looked up wind chill index definition, and then used the US formula of wind chill, did that calculation, and put that on the plot as well:


storm day data


The data logger can be configured to average over just about any interval.  Ours is set for 1 minutes averages, but it could have been set for 10 minutes, 1 hour, etc.  In addition to the average for the interval, the data logger saves the maximum, the minimum, and the standard deviation (SD).  SD is a measure of the variability during the interval.  Also each interval, naturally, has a date and time stamp.

From the plot above, you can see that temperature (red trace) changes much more slowly than wind speed (blue trace).  To calculate the wind chill (black trace), I used the maximum wind speed in the 1 minute averaging interval, as this would be a measure of the lowest perceived temperature.  (Now – Friday 1/30, and the snow is coming down again!)

Is Your Anemometer Wind Sensor Wind Tunnel Calibrated?

Etesian Technologies can’t speak for other manufacturers of wind speed measurement systems, but every anemometer manufactured and sold by Etesian is calibrated in our custom designed wind tunnel.  We do this because we believe our customers want and need this level of accuracy in their wind speed measurements.

I would like to describe the process of calibrating our anemometers.  The sketch below was used for the fabrication of our wind tunnel.  We hired a retired journeyman cabinet maker/artist/marketing wiz to do the actual fabrication.

The tunnel consists of three sections – the inlet, the test section, and the outlet which includes a large 36 inch 2 HP fan.  Between the inlet section and the test section is a 2 inch thick polymer “honeycomb” which straightens the air prior to entering the test area.

WindTunnelConstructionSketch (1)The photo below provides a nice view of the test section and the honeycomb that directly proceeds it.  The test section has enough room for 3 sensors – the sensor being calibrated, and two reference sensors: a Class 1 cup anemometer, and a differential pressure transducer coupled to a pitot tube.  



All 3 sensors are data logged with our standard Model 201 data logger.  The logger is set for 1 minute averaging.  The wireless sensor transmits the data to the 201, the two reference sensors are wired to the optional analog inputs.



The process then is to vary the speed of the fan.  We have a 2 HP continuously variable speed fan that can be used to set the speed in the test section from about 3 MPH on the low side to just under 40 MPH at the top end.



We typically set the speed (as indicated by the reference sensors) to 10, 15, 25, and 35 MPH. We hold the tunnel at each speed for 1 minute to enable logging of 1 full minute of data at each speed.  The logger samples once per second minimum, and averages these 60 points to create a 60 sample average for the references and the sensor being tested.  Every anemometer ends up with a calibration certificate.  These are held on file here for all of our customers.  Below is a typical certificate:

Plot riso vs etesianIf you have any questions about our calibration practices, or are interested in knowing more about our tunnel testing give us a call or send us an email.


Etesian Technologies Email Has Been Compromised

Our post today unfortunately has to take a detour of sorts.  Over the past two or three weeks we have had the misfortune of having spammers using our email address in the reply-to field in the heading of their “emails”.  What this means is that every day we (Etesian ) receive between 10 and 100 emails that say “Undeliverable” or something like that, indicating that the spammer sent their so-called email to a non-existent address.

But even worse, some email providers now believe that Etesian Technologies is a spammer and bona fide email coming from us is being sent to the junk folder for many of you.  We have been discovering this on a case-by case business, and have been forced to use personal email accounts to insure that the mail gets through.

To remedy the situation, Etesian Technologies now has a new email address.  I won’t publish it here.  Publicly posting our email is probably how we got compromised in the first place.  I just wanted to let everyone know that you will see a new email address from Etesian.  It is legitimate, and hitting the reply-to button will get your message back to us safely.  Thanks for your understanding.


Happy Holidays from all of us here at Etesian Technologies

Going the Distance – Just how far will my breeze anemometer transmit?

Sometimes we get asked to supply our anemometer for situations that are quite different than the typical crane or fountain control wind indicator.  One such time a couple of years ago was by SpaceX.  Yes the SpaceX putting rockets into orbit and supplying the international space station.  They needed more than 700 feet as I recall and we decided that it would be best to supply the wind sensor with an external high gain directional antenna.

Normally the anemometer is supplied with a small fixed omnidirectional antenna, and this is just fine for transmitting up to about 500 feet with a good Yagi antenna connected to the receiver.  We sell hundreds just this way.  We don’t really advertise it, but this fixed antenna can be replaced with a connector so that just about any type of external 900 MHz antenna can be attached to the sensor.  The regulations for the Industrial/Scientific/Medical aka ISM band at 900 MHz limits the Effective Isotropic Radiated Power (EIRP) to 36 dBm.  Our sensor is 0 dBm and about the largest practical Yagi is perhaps 18 dBi.  EIRP is calculated by adding the transmitted power (0 dBm) to the antenna gain (18 dBi) , in this example then, an EIRP of 18.  I have seen small dish antennas of perhaps 24 dBi.

Putting a high gain directional antenna on the receiver helps as well, and there is of course no limit on how high a gain antenna you put on the receiver, only the transmitter.  Some day we will put a couple of big dish antennas on one of our systems and put the sensor our in the middle of Boston harbor or some other coastal location, just to see how far we can transmit with the breeze wireless anemometer.

For SpaceX we put small Yagis on both the transmitter and receiver, and started marching down the road from our facility with the receiver in hand, just to see how far we could go and still get a reading.  We put the anemometer on the ground with a window fan in front of it to keep it turning at about 6 mph.  We then clamped the Yagi to a short step ladder and aimed it to the location where we thought we might end up with no signal.IMG_0224                Bad photo of wireless wind sensor fixed in front of window fan


                     The next photo is of the Yagi antenna cabled to the sensor

We power the readout with a 9 volt battery, and we have our usual 6 dBi yagi attached to it.  Now we start walking, with all this in our hands:


Down the road.  Here is a Google map indicating the distance covered before reception stated to get spotty.

distance map spacexThe final distance was 1476 feet, and this was way less than ideal conditions.  The sensor was close to the ground, and we had brush and trees along the way.  More generally you will have the wind sensor mounted much higher above the ground and this will certainly improve the transmission and increase the transmission range.  Additionally, we could have gone back to the wind sensor antenna and aligned it to point at a further distance down the road and gained more distance too.  But the point of this test was to insure that SpaceX would have a working system with plenty of headroom for whatever obstacles that their installation might introduce.

What’s a “BreezeSonic”?

Etesian Technologies was formed back in 2007.  The company was launched to manufacture and sell its patented wireless and self-powered wind speed sensor (anemometer).

Along the way, Tony Groat at IPAF, noticed our anemometer and gave us a call to talk about using it on Aerial Work Platforms (AWP).  It didn’t seem to me at the time that our wireless wind meter was really suited to AWPs.  As we talked about it, the germ of an idea came to me.  When an AWP operator is busy with the task at hand -literally, (s)he shouldn’t have to be distracted to pull out a pocket wind measurement tool, turn it on, and face it into the wind to take a reading.

BreezeSonic 288x384

BreezeSonic – A Self-Powered Anemometer with 95 dB Audible Alarm

Suppose instead, that the senor works more like a smoke detector, operating in the background and if danger is present, sound an alarm.  And this is exactly what the BreezeSonic does.  At a factory preset wind speed, (generally 25 MPH, but this can be changed based upon the safety limits of the AWP) a piercing audible alarm sounds.  But we did the smoke detector one better.  We eliminated the dead battery problem.  Borrowing the self-powered concept of the Breeze Wireless, we incorporate an internal generator, driven by the very wind it is measuring, to power the signal conditioning and a 95 dB audible alarm.  This anemometer doesn’t even have an on/off switch!  The BreezeSonic is intended to be mounted on a short mast that clamps to the platform guard rail, so that it sits a foot or so above the operator’s head.  This allows for a clean wind speed measurement, and it puts the alarm at an optimum position to be heard.

Wind Data Logger – Wind Turbine Power Curves

Is your wind turbine operating as intended?  Is it producing the power that the manufacturer claims it should? Is it regulating properly so that you know if a storm passes through, it won’t self-destruct or burn out the generator and inverter?   The only real way to determine that is to measure both the turbine power and the wind speed.  If you don’t measure the wind speed you are only guessing.

Etesian’s wireless self-powered anemometer makes it especially easy to retrofit an anemometer to an existing wind turbine.  Perhaps you already have the wind turbine installed at your home or business and didn’t install an anemometer when the turbine went up.  To add a conventional anemometer would require running the anemometer signal cable from the wind turbine tower back to the garage or control shed where the turbine controls are located.  With a wireless sensor the hassle and expense of trenching, laying conduit, and pulling a cable is eliminated.  All that’s needed is short boom mounted to the side of your existing wind turbine tower with the cup anemometer installed on it.

Pieperpower Installation

Etesian Breeze anemometer on boom below blade path

Secondly, you need a means to measure and record the turbine power.  Etesian provided a system last year to Black Island Wind Turbines ( Their 3 kW HR3 turbine was being evaluated by the DOE.  The DOE had contracted with an independent test facility – the Alternate Energy Institute (AEI) at West Texas A&M University (WTAMU) in Canyon.  This particular turbine generated 24 VDC and was fed thru a grid tied inverter back to the local utility.



HR3 Turbine installed at AEI, WTAMU, Canyon, Tx

The generator voltage was held at 27.6 volts, as it was feeding a very small battery bank consisting of two automotive type L-A float batteries.  All that was needed to measure the turbine output was to measure the DC current fed to the battery bank and inverter.  For that purpose Etesian provided one of its wind data loggers with an analog input option, the current measurement being made with a Hall Effect “CT”


FW Bell Hall Effect Current Transducer

With the self-powered wireless anemometer sensor sending data from a few hundred feet away, and the current transducer feeding the generator current signal to the logger everything that was needed to graph power vs wind speed was in place.  The Etesian logger receives wind measurements from the wireless sensor once per second, and it samples the analog voltage input once per second.  If you plotted the one second data you would have a huge amount of scatter in the plot as gusting winds change velocity quickly and the rotating mass of the wind turbine responds much more slowly to these changes.  Typically the data is averaged over a time period and this is exactly what the Etesian logger does.  It can be configured to take the one second samples of wind and power and create one minute (or longer) averages along with other important measures in the averaging interval: the maximum, the minimum, and the standard deviation.

So, what’s a power curve look like, and what does it mean?  As the wind blows harder, (up to a point) the power generated by a wind turbine increases.  I guess this is obvious.  No wind – no power, more wind – more power.  At some point the turbine reaches the capacity of its electrical generator and something has to be done to regulate the torque from the blades driving the generator.  Otherwise the generator will overheat and be toast.  Not a good thing, and another important reason to want to be able to create a power curve for your turbine. Below is the power curve from the HR3 at AEI on October 28, 2013:

hr3 power curve


Contained on this scatter plot is a day’s worth of one minute averages.  Each dot (and there are 24 hrs x 60 min/hr = 1,440 dots) is the logger’s average of the wind speed and the average of the turbine power for that one minute.

What’s interesting about this power curve is to note that at about 22 MPH the general increase of power with increasing wind speed stops.  You can see that the curve flattens out and actually starts curving down – the power is going down with increasing wind.  It’s too bad there were not higher winds that day.  It would have been nice to see the graph filled in from 25 to say 35 or 40 MPH.  But the point is, this turbine was regulating properly.  You can visit Black Island’s site for details on their turbine and how it works.