Need a small wind speed sensor for an RC boat

Thread Starter

StrongPenguin

Joined Jun 9, 2018
241
I am planning on building an RC boat, which has certain features, like auto heading and "automatic hold position". In order for the thrusters to know how much to thrust, a small wind sensor would be helpful.

Can any of you guys recommend me one?
 

Bernard

Joined Aug 7, 2008
5,562
Just some hints that I heard long ago. To keep size small , grain of wheat sized thermistors are constant current, electrically heated , one in air stream one protected. no wind both at same temp., same resistance, same differential V. Breeze cools one, R up, V up porportional to wind speed ?
Did not see one on 'net.
 

Thread Starter

StrongPenguin

Joined Jun 9, 2018
241
@AlbertHall I would like the sensor to be as small as possible, let's say about 10 cm high, but it is not set in stone. Yes, I need direction and speed.

@Bernard That is a very good idea, If I can't find a real sensor. But I would really like to find some kind of windmill looking thing, that sets it's nose in the wind direction. I guess there is also the possibility of making one, just need to find a very small generator :confused:
 

andrewmm

Joined Feb 25, 2011
403
Would a 9DOF sensor not be all you need to hold position,
The only use of wind information I can think of is in a Sail boat, but as you mention thrusters , I'm doubting you have a sail boat.

GPS / magnetometer / gyro in a 9DOF sensor will hold you very still.
Its the difference between accuracy and resolution.
its not a great accuracy, but a great resolution thats stable.
It might not know your position to more than m resolution, but it will hold you there plus or minus cm.
 

Bernard

Joined Aug 7, 2008
5,562
Just some thoughts. A ring of 8 reed switches but reeds do not operate in uniform manner from make to break so thought of Hall effect sensors. 8 in a ring with a magnet on wind vane would give 8 positions, but if 2 sensors are on at the same time then we would have 16 positions.
Add a 3 cup anemometer, magnet & Hall = 1 pulse / revolution.
Or then there is a 4 track Gray code disc to give 16 positions which will consume more current than Hall @ 4 mA, R-S 276-1649 ? Small ready built would be better.
 

andrewmm

Joined Feb 25, 2011
403
If you want to measure angles, rotate a magnet and use a sensor like these
https://www.digikey.co.uk/product-detail/en/infineon-technologies/TLV493DA1B6HTSA2/TLV493DA1B6HTSA2CT-ND/5891933
This one uses I2c, others are SPI, or Analog voltages

( they are basically one part of a 9DOF sensor )

This is similar built into a housing,
http://switches-sensors.zf.com/us/wp-content/uploads/sites/7/2012/10/Angle-Position-Sensor-AN8-Datasheet.pdf

dont know if its low enough friction,

Older techniques include Rotary transfomers , and optical encoders,
https://www.digikey.co.uk/product-detail/en/cts-electrocomponents/292V1X00A/119-292V1X00A-ND/12091629
 

Bernard

Joined Aug 7, 2008
5,562
If you have a binary number ( decoded Gray ) for wind speed then a digital magnitude comparator
( 74HC85 ) could give direction to turn the boat for desired effect . This is used to turn the head of a owl to match a random selected direction.
 

Janis59

Joined Aug 21, 2017
1,187
I have a similar wish however for aim of sailing seems more important the wind direction not a speed per se. So, if to mind any ultrasound device and simplest "absolute rotation encoder" at TME having price about 40 Eur (real ball bearings, metall inside and outside), seems the second idea is simpler, more accurate and cheaper. Yet it will show the wind direction along the yacht COURSE not a Northpole, actually the first one is those a sailor needs, not a second. Ah ya, encoder must be installed instead of shaft of 50-cent worth aerodinamic wind direction "arrow". Like this https://thumbs.dreamstime.com/z/silhouette-vintage-retro-weather-vane-instrument-showing-wind-direction-arrow-pointing-towards-north-silhouette-vintage-167800885.jpg

However, if indeed the wind speed is having importance, may apply the second encoder with horizontal shaft monitoring the heavier lamelle angle above the vertical. Only complication then is cordless power supply thus the RF mutual coils.

PS: No, simpler will be Newton cups rotating and read by hercon or alternatively Hall sensor. Cheap and no need for any rotating contacts cabling. Hercon have genuine capability to read between 1E6 1nd 1E7 clicks, thus the decades of years long service life is not a problem. However Hall is sure better yet more tricky.

Newton cups are seen here, may make a diy only then the graduation is a big deal. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTa_eBzN1ObN0MYJMqymixuPBfRjr6o-z8dvQ&usqp=CAU
 
Last edited:

ci139

Joined Jul 11, 2016
1,574
no matter my terrifying prev. entry such only occurs on the wavy/windy day + the time average of the surface share would give you the mean higher elev.
 
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