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Fine Offset - Cheapest Good Enough Sensors?
#1

I want a micro-controller weather station that uploads to Weather Underground and this site is a mine of information.

Through it I have discovered that most cheap weather stations whatever their brand use Fine Offset external sensors and it would appear they are good enough. I could buy this popular model with solar charging for A$139.00 which gets some positive comments from Werk_AG. The rainfall and wind speed use reed switches and the wind direction uses resistors . It uses this transmitter which adds temperature, humidity and solar radiation (from the solar cell) and transmits it all over a 433MHz radio signal using this protocol.

Therefore I could either connect the reed switches to a Weatherduino Pro2 Tx station, replacing the transmitter or decode the existing 433MHZ signal at a base station. Is everything I've said correct so far?

There is a new Fine Offset weather station with all of the features of the previous one at an amazingly low price of A$90.00. It looks like it will be neater too, with all of the cabling internal. Am I right to assume this is a good replacement for the above mentioned model with all the same methods of operation and features?

I also have some queries regarding the 433MHZ communication which I asked in the AuriolDuino - General Discussion thread.
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#2

Here you can buy an FO rain gauge, wind vane, and anemometer for £15.00 add a SHT10 with a £7.00 FO radiation shield and you have a station, however there is a direct correlation between accuracy and cost of sensors. The FO raingauge in particular is a bit vague, see other posts on rain gauge calibration. http://www.meteocercal.info/forum/Thread...15#pid2315

Davis or Inspeed are best, or best of all find some research grade stuff being sold off the end of project. Ebay often.

FO will work but they will produce a representation, rather than an accurate measure.
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#3

Hi,

As JT118 says, the Rain and Wind sensors can be bought (in UK) for about £17.50, which is probably all you can re-use simply. AFAIK the "Solar Pod" (data) is not easily compatible with the WeatherDuino, nor is the "wireless protocol" of the External Temp/Humidity Transmitter. But both have been "hacked" if you're confident about your microcontroller-programming abilities. Note that the Solar Charging is a "worthless" feature because the Rechargeable Alkaline battery technology is basically "rubbish".

(05-02-2016, 04:33)ken66 Wrote:  There is a new Fine Offset weather station with all of the features of the previous one at an amazingly low price of A$90.00. It looks like it will be neater too, with all of the cabling internal.

As far as I can see, that station does NOT have Solar Data , nor a PC interface. So you couldn't start with an "off the shelf" trial setup using Cumulus, until you get the final WeatherDuino built and running. If you're just going to use the Wind/Rain sensors, then is it a good idea that the cables are "internal" ?

IMHO the (original) Fine Offset Wind/Rain sensors are probably a better starting point than complete "Home Build" sensors. There are plenty of ideas (e.g. on the Cumulus forum) how to "improve" and then calibrate them. Therefore I suggest buying those in the most convenient and economical manner, which might well be as a complete off-the-shelf FO ("branded") station at a best offer price.

Cheers, Alan.

PS: In the UK, the Solar Data (WH-30xx) stations cost almost twice as much as the "touchscreen" (WH-10xx) versions. In Australia the prices seem rather similar which apparently makes the Solar Data version rather a "bargain". However, the early Solar (Data) Pods had serious flaws, which maybe haven't been fixed on those cheap ones ?
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#4
Photo 

Thanks for the advice.

@JT118. Conflicting views made it difficult to gain an understanding from the the thread you referred to but I came across a "15 Jan 2014 Rain Sensors Compared" post in the "Notes about the process" section in the page http://lancet.mit.edu/mwall/projects/weather/ where they compared FineOffset WS2080, LaCrosse WS2317, and Meade TE923W during rain events and found "The WS2080 regularly under-reports rainfall." Looking at their plots it seems the other 2 substantially disagreed a lot of the time too. I couldn't see an obvious pattern in the differences.
[Image: weewx-rain-comparison-1.png]
[Image: weewx-rain-comparison-2.png]
[Image: weewx-rain-comparison-3.png]
@AllyCat. Thanks for pointing out the absence of Solar Power/Data. I'd missed that but was aware of the absence of a PC interface. I'm not in a hurry to get data uploading, more interested in the technology and there is other stations nearby for data in the meantime.
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#5

I note the link comes from the esteemed MIT, however they are all cheap gauges. Davis is about as good as one gets at a sensible price and can be got for £50.00 Or more.
http://www.skyview.co.uk/acatalog/DAV_7852.html

I am afraid this info is all bit UK biased but might give some ideas.

.docx Station 1.docx Size: 17,49 KB  Downloads: 341
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#6

(17-02-2016, 22:19)JT118 Wrote:  I note the link comes from the esteemed MIT...

It is the sailing club rather than regular MIT research but I like the way they do things. Measure stuff, compare things, share the data and try to explain it. Thanks for further advice and I can see the Davis gauge has things like calibration by screw adjustment, leveling indicators and so on. It certainly looks more professional, but you pay for it.

I couldn't open the attachment which I was curious to do. I don't have Word but Google Docs will usually read Word docs. In this case it couldn't.
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#7

(18-02-2016, 01:20)ken66 Wrote:  
(17-02-2016, 22:19)JT118 Wrote:  I note the link comes from the esteemed MIT...

It is the sailing club rather than regular MIT research but I like the way they do things. Measure stuff, compare things, share the data and try to explain it. Thanks for further advice and I can see the Davis gauge has things like calibration by screw adjustment, leveling indicators and so on. It certainly looks more professional, but you pay for it.

I couldn't open the attachment which I was curious to do. I don't have Word but Google Docs will usually read Word docs. In this case it couldn't.

Doc might work now.
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