Ultrasonic Anemometer

S

Skiwi

New Member
Hi
Has anyone experience or advice on using an ultrasonic anemometer. I see lots of info on wind vane versions.
There are sales on aliexpress for reasonable prices, (NZ$16.66) but that makes me suspicious as to what you get for the cost.

485 Ultrasonic Wind Speed & Direction Sensor High Precision Environmental Monitoring Anemometer Integrated Transmitter - Air Conditioner Parts - AliExpress

Others on ebay and 'reputable' instrumentation company sites sell for thousands, which makes them out of consideration for a simple project
 
P

papaof2

Senior Member
AliExpress and Banggood are known for putting the lowest price of any add-on bit in the header of their ads, regardless of the actual item mentioned in the ad.

Go back and read the fine print. Types 1-12 have the ultrasonic sensor and the prices are $260USD and UP.
That might mean that they are useful.

I'd expect to find Types 18 and 19 in the $10USD range.

Type 1: 485 Ultrasonic wind speed and direction, without rod top holding seat

Type 2: 4~20mA Ultrasonic wind speed and direction, without rod top holding seat

Type 3: 0~5V Ultrasonic wind speed and direction, without rod top holding seat

Type 4: 0~10V Ultrasonic wind speed and direction, without rod top holding seat

Type 5: GPRS type Ultrasonic wind speed and direction, without rod top holding seat

Type 6: 4G type Ultrasonic wind speed and direction, without rod top holding seat

Type 7: 485 Ultrasonic integrated weather station, without rod top holding seat

Type 8: 4~20mA Ultrasonic integrated weather station, without rod top holding seat

Type 9: 0~5VUltrasonic integrated weather station, without rod top holding seat

Type 10:0~10V Ultrasonic integrated weather station, without rod top holding seat

Type 11: GPRS Ultrasonic integrated weather station, without rod top holding seat

Type 12: 4G Ultrasonic integrated weather station, without rod top holding seat

Type 13: temperature and humidity

Type 14: Noise

Type 15: pm2.5,pm10

Type 16: Amospheric pressure

Type 17: Carbon Dioxide

Type 18: rod top holding seat

Type 19: Beam bracket
 
Buzby

Buzby

Senior Member
Many years ago I worked for a company that built ultrasonic gas flow meters. I should imagine the principle of operation is the same as these anemometers.

For the flow meter, a pulse of sound is sent twice, one in each direction. By measuring the difference in the time-of-flight it is easy (!) to calculate the speed of the gas. Put two sets of transducers at right-angles to each other, with lots more maths, and you can get speed and direction.

I can't imagine that the £250 ones are rubbish, as the code is quite straightforward. The difficult part is the analogue interfaces to the transducers, but I would expect that this has been sorted, as it was 20 years ago when I was involved.

( Regarding cost of commercial to retail, look at the price of pulse oxymeters. Retail two for £20, but over £3,000 for a hospital device. If your life depended on it how much would you pay ? )

Here's an off-the-wall idea to build your own ultrasonic anemometer !.

Get two secondhand gas meters, repackage the gubbins, then add some PICAXE maths.

Cheers,

Buzby
 
S

Skiwi

New Member
papaof2 said:
AliExpress and Banggood are known for putting the lowest price of any add-on bit in the header of their ads, regardless of the actual item mentioned in the ad.

Go back and read the fine print. Types 1-12 have the ultrasonic sensor and the prices are $260USD and UP.
That might mean that they are useful.

I'd expect to find Types 18 and 19 in the $10USD range.

Type 1: 485 Ultrasonic wind speed and direction, without rod top holding seat

Type 2: 4~20mA Ultrasonic wind speed and direction, without rod top holding seat

Type 3: 0~5V Ultrasonic wind speed and direction, without rod top holding seat

Type 4: 0~10V Ultrasonic wind speed and direction, without rod top holding seat

Type 5: GPRS type Ultrasonic wind speed and direction, without rod top holding seat

Type 6: 4G type Ultrasonic wind speed and direction, without rod top holding seat

Type 7: 485 Ultrasonic integrated weather station, without rod top holding seat

Type 8: 4~20mA Ultrasonic integrated weather station, without rod top holding seat

Type 9: 0~5VUltrasonic integrated weather station, without rod top holding seat

Type 10:0~10V Ultrasonic integrated weather station, without rod top holding seat

Type 11: GPRS Ultrasonic integrated weather station, without rod top holding seat

Type 12: 4G Ultrasonic integrated weather station, without rod top holding seat

Type 13: temperature and humidity

Type 14: Noise

Type 15: pm2.5,pm10

Type 16: Amospheric pressure

Type 17: Carbon Dioxide

Type 18: rod top holding seat

Type 19: Beam bracket
Click to expand...
Thanks for that, I was getting a bit impatient with the site.
papaof2 said:
AliExpress and Banggood are known for putting the lowest price of any add-on bit in the header of their ads, regardless of the actual item mentioned in the ad.

Go back and read the fine print. Types 1-12 have the ultrasonic sensor and the prices are $260USD and UP.
That might mean that they are useful.

I'd expect to find Types 18 and 19 in the $10USD range.

Type 1: 485 Ultrasonic wind speed and direction, without rod top holding seat

Type 2: 4~20mA Ultrasonic wind speed and direction, without rod top holding seat

Type 3: 0~5V Ultrasonic wind speed and direction, without rod top holding seat

Type 4: 0~10V Ultrasonic wind speed and direction, without rod top holding seat

Type 5: GPRS type Ultrasonic wind speed and direction, without rod top holding seat

Type 6: 4G type Ultrasonic wind speed and direction, without rod top holding seat

Type 7: 485 Ultrasonic integrated weather station, without rod top holding seat

Type 8: 4~20mA Ultrasonic integrated weather station, without rod top holding seat

Type 9: 0~5VUltrasonic integrated weather station, without rod top holding seat

Type 10:0~10V Ultrasonic integrated weather station, without rod top holding seat

Type 11: GPRS Ultrasonic integrated weather station, without rod top holding seat

Type 12: 4G Ultrasonic integrated weather station, without rod top holding seat

Type 13: temperature and humidity

Type 14: Noise

Type 15: pm2.5,pm10

Type 16: Amospheric pressure

Type 17: Carbon Dioxide

Type 18: rod top holding seat

Type 19: Beam bracket
Click to expand...
Thanks. Viewing on tablet was my problem, Via PC I can see it properly now.
ModBUS protocol might be an issue for using Picaxe. Off to do more research
Cheers.
 
S

Skiwi

New Member
Buzby said:
Many years ago I worked for a company that built ultrasonic gas flow meters. I should imagine the principle of operation is the same as these anemometers.

For the flow meter, a pulse of sound is sent twice, one in each direction. By measuring the difference in the time-of-flight it is easy (!) to calculate the speed of the gas. Put two sets of transducers at right-angles to each other, with lots more maths, and you can get speed and direction.

I can't imagine that the £250 ones are rubbish, as the code is quite straightforward. The difficult part is the analogue interfaces to the transducers, but I would expect that this has been sorted, as it was 20 years ago when I was involved.

( Regarding cost of commercial to retail, look at the price of pulse oxymeters. Retail two for £20, but over £3,000 for a hospital device. If your life depended on it how much would you pay ? )

Here's an off-the-wall idea to build your own ultrasonic anemometer !.

Get two secondhand gas meters, repackage the gubbins, then add some PICAXE maths.

Cheers,

Buzby
Click to expand...
hmmmmm!. Interesting idea. Thanks
 
A

AllyCat

Senior Member
Hi,

I'm late to the party on this one because I've been travelling, but many, many years ago I did develop such an ultrasonic "time of flight" air speed sensor for a single axis (i.e. along a tube) using standard "consumer" ultrasonic transducers. As Buzby said in #2, the principle is simple; compare the forward and reverse transit times along two axes at right-angles and it's quite easy to calculate the angle and speed vector of any air flow (in a horizontal plane). The mathematical calculation is not difficult (I've posted suitable trigonometric functions in the Code Snippets section) but sadly many PICaxe users seem to be frightened by maths in general. A great advantage is that the wind-speed can be calculated directly from the physical properties (in particular the speed of sound in air), there is no need for a "reference" standard anemometer to calibrate the system.

Those AliExpress prices look remarkably high, because the company Ecowitt (originally known as Fine Offset, a manufacturer of Low-Cost weather stations) sell a complete external sensor array including ultrasonic anemometer (to replace their normal wind speed cups and direction vane), temperature, humidity, rain, solar (data and power supply) including a wireless transmitter for only just over $100. Sadly, they don't appear to sell the anemometer separately (now) and I don't know if anyone has "hacked" their wireless protocol yet (any of the usual ISM bands). There's lots of information on the Cumulus website such as here.

Do you just require a ready-made anemometer or to develop your own system? For external use, car reversing sensors may be more rugged than normal "remote control / ranging" ultrasonic transducers. You could measure a simple (40 kHz modulated) pulse time of flight, but short time delay measurements are not one of PICaxe's strengths, so an alternative method (which I used) is a phase comparison of the send/receive signals (using a simple Flip-Flop, Low Pass filter and ADC). If the path length is only a few wavelengths, then the phase shift is unlikely to exceed +/- 180 degrees.

Cheers, Alan.
 
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