Author Topic: Fine Offset  (Read 14132 times)

WCDev

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Fine Offset
« on: August 25, 2012, 06:58:58 PM »
So we get more requests to support Fine Offset stations than anything else - I've honestly lost count of the number enquiries for this hardware. These are rebranded to many names and Maplin are currently doing a good deal on the WH1081, so yesterday, as if by magic, one arrived - £59 including all taxes.

Today, seeing as it's raining, I thought I'd set it up :)

Assembly isn't too difficult, but there are screws and bolts of varying lengths and it isn't totally clear which goes where. In the kit you get a slim, two part pole which holds all the sensors. Wind is taken care of by a wind vane and anemometer - these mount on one plastic beam which sits on top of the pole. The rain bucket mounts on another beam, which clamps to the pole and the thermo/hygro unit mounts on another beam, which again is clamped to the pole. I've attached some images - ignore the Davis ISS below, it was just convenient for me to bolt the Fine Offset pole to the pole holding the ISS. This is not the ideal location for the anemometer, but as you can see it's only a  temporary installation to get some data. Cath, is not happy :)

The rain bucket (I'd strongly recommend moving it off the wobbly plastic beam and mounting it more securely) and anemometer plug into the the thermo/hygro unit which takes two AA batteries - the manual claims these will last for 24 months (they won't).

Inside, the touch-screen console (see attached images) sits on my desk - this takes three AA batteries (12 months life claims the manual). The wireless connection seems fine, with no problems picking up the signal from the thermo/hygro unit at least initially.

What we're going to do is monitor how stable/reliable it is. My job tomorrow is to start hacking the data and putting the station driver together. I know there are some issues with this hardware - the data-logger doesn't time stamp entries for example, and the update rate of 48 seconds is a lot slower than I'd like, but if we can get it going and it's reliable we'll put it out for a test run.

I'll update as things progress....
 

Steve

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Re: Fine Offset
« Reply #1 on: August 25, 2012, 07:57:24 PM »
Cool! THis is going to generate a lot of interest. THe only downside I see is cost. A $79 application to use a $400-1200 station is fine, $79 to run a $99 station might be harder to swallow until the new user tries WC and finds how easy it is to use and how configurable it is.

Thanks for starting on this,
Steve
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elagache

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Hurray!! Glad to see it!! (Re: Fine Offset)
« Reply #2 on: August 25, 2012, 08:16:08 PM »
Howdy Stu, Steve, and WeatherCat fans,  [cat]

So we get more requests to support Fine Offset stations than anything else - I've honestly lost count of the number enquiries for this hardware. These are rebranded to many names and Maplin are currently doing a good deal on the WH1081, so yesterday, as if by magic, one arrived - £59 including all taxes.

Hurray!!  I just had to send someone on MacWeather to Weather Snoop because they had bought one of these and . . . . *sniff*

Today, seeing as it's raining, I thought I'd set it up :)

 ;) Hmm, does that mean you cannot set up a weather station unless it is raining? Golly, nobody ever told me that!!  [lol2]

Thanks for all the detailed info on the installation.  I know so little about other models that when folks ask questions about them . . . I can't help but think: "couldn't you just buy a Davis station that I know something about?"  ;)

It is good for all of us to have some idea of how the various weather stations go together and perform.  Thanks to modern digital cameras, not as hard to document such things as it once was.

Thank Stu for all the things you do!!

The only downside I see is cost. A $79 application to use a $400-1200 station is fine, $79 to run a $99 station might be harder to swallow until the new user tries WC and finds how easy it is to use and how configurable it is.

Well, that's true, but what alternative to Mac users really have?  It might take some gentle persuasion, but there is only WeatherCat and WeatherSnoop and they cost about the same.  I went a year with my Oregon Scientific 968 that wasn't connected to my computer and . . . . what a difference when I got LWC!!  [bounce]

Just gotta explain what you gain!!

Cheers, Edouard  [cheers1]

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Re: Fine Offset
« Reply #3 on: August 25, 2012, 10:18:29 PM »
These (re-branded) models are very popular here down under, and I have been asked many times if WC will work with them.

I have heard they are often unreliable but parts are replaced under warranty , no questions asked, so people seem to keep with them.

I will follow your progress with interest.

Tony

Steve

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Re: Hurray!! Glad to see it!! (Re: Fine Offset)
« Reply #4 on: August 26, 2012, 12:29:12 AM »
Well, that's true, but what alternative to Mac users really have?  It might take some gentle persuasion, but there is only WeatherCat and WeatherSnoop and they cost about the same.

True for the most part. Ambient sells their version of the Fine Offset models bundled with WeatherSnoop Lite, and WeatherSnoop Lite is available as a standalone product. It still processes data and uploads to WU, PWS, CWOP and a basic web page (I think) but doesn't have the gauges to display on your desktop. I think it is $29.

We just need to convince the people questioning the value of WC compared to their initial investment. Remember just shy of a year ago, I was all set to spend $109 on the Ambient system to see if I'd like observing local conditions. Y'all convinced me to spend $97,000 on my system instead, and I'm glad you did!  ;D
Steve - Avon, Ohio, USA


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WCDev

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Re: Fine Offset
« Reply #5 on: August 26, 2012, 09:13:38 AM »
Remember just shy of a year ago, I was all set to spend $109 on the Ambient system to see if I'd like observing local conditions. Y'all convinced me to spend $97,000 on my system instead, and I'm glad you did!  ;D
ROTFL.

Agreed though, it's a bit of a risk. Development of a station driver for new hardware starts at about £600 and goes up from there (depending on facilities and weirdness of the hardware). In this case I'm hoping to get just the basics going so I can leave it sit on test to check reliability. If the test goes Ok then I'll flesh it out a bit and put it out for public test. If it doesn't, then I'll just drop it.

If it looks good  and it makes it in, then the enquiries I've had suggests we should at least be able to recoup the development costs.

Now, as the sensor suite is sitting in the same place as the ISS and the console is sitting right next to the Vantage console,  I thought, (because I need the data), it'd be good to see how the readings compare (we have to ignore wind as the 1081 anemometer isn't situated correctly). The 1081 has been running overnight so should have settled down by now.


Variable   Davis    Fine Offset
Ext. Temp °C   10.8   11.6
Ext. Hum %   95   91
Baro (rel) hPa   1013.5   1013.6
Daily Rain mm   0.2   0
Int. Temp °C   21.6   21.5
Int. Hum %   54   66

So for the important things (ext temp, hum and baro) it doesn't look too bad (you might say the ext. temperature is a bit high, but the ISS has a 24 hour fan and there is some solar radiation already (~100W/m^2) - I'll check it again a few hours after dark). The Fine Offset rain bucket is 0.3mm, so we can't check that yet as unusually, we've only had a sprinkling of rain since midnight - I'll update when we get some more rain.

Steve

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Re: Fine Offset
« Reply #6 on: August 26, 2012, 01:52:48 PM »
So for the important things (ext temp, hum and baro) it doesn't look too bad (you might say the ext. temperature is a bit high, but the ISS has a 24 hour fan and there is some solar radiation already (~100W/m^2) - I'll check it again a few hours after dark).

Stu,

Take a look at this radiation shield from Ambient. In almost any discussion or review of these various Fine Offset systems, it is almost universally recommended to upgrade to the larger radiation shield to have any hope of getting accurate measurements. Maybe your supplier has the equivalent he can obtain for you.

http://www.ambientweather.com/amwesrpatean.html

Steve
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Weather station with "training wheels" (Re: Fine Offset)
« Reply #7 on: August 26, 2012, 10:11:44 PM »
Howdy Stu, Steve, and WeatherCat fans,

Interesting discussion here.  I hope Stu that you can manage to somehow coax WeatherCat to work with the Fine Offset without too much pain.  Even if it doesn't seem worth the effort directly, there might be benefits that even folks like Davis would appreciate.

There is a flip-side to Steve's point about the low cost of the Fine Offset.  Until, you've had a weather station, it is really hard to understand what you are going to get out of it.  If I hadn't had that Oregon Scientific station, I wouldn't have forked the $500+ for the Davis VP-2.  I needed to see things like: Having a well located and accurate thermometer really did help me understand what was going on in the yard.  An automated rain gauge is much more useful than you realize because it can measure rainfall rates in "real time" and so on.

Lots of folks are going to need a "weather station with training wheels" before they satisfy themselves that a station like Davis is truly worth the investment.  It is a reasonable response.  Folks like us are a little too enthusiastic to be fully trusted.  Sometimes you've gotta experience things for yourself.

So if you can "hook'em" early with WeatherCat,  ;) they'll be "putty in our hands" . . . . (errr . . . . . I mean they'll be much more receptive to our sage advice about quality weather station hardware . . . . )

Cheers, Edouard  [cheers1]

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Re: Fine Offset
« Reply #8 on: August 27, 2012, 11:28:29 AM »
I have to agree with Steve, this station is very cheap and as a result can be very inaccurate.
I personally wouldn't bother investing in a driver for a very low grade weather station but that is my opinion.

Stu, you have developed a premium Weather Station software product, as Steve said the software costs nearly as much as the hardware.
That wouldn't sit well with me either.

In the Windows environment it may bit easier to implement as the driver is available, but on OS X/Unix its completely different.

If you were to integrate new Weather Stations into WC, I personally think the higher end would be more beneficial such as the Viasala WXT520 etc.



WCDev

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Re: Fine Offset
« Reply #9 on: August 27, 2012, 05:56:24 PM »
Thanks for the discussion folks - interesting stuff. With no solar loading, the temperature and humidity match the Vantage, so you're absolutely correct Steve, a better radiation shield would definitely help.

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Re: Fine Offset
« Reply #10 on: August 27, 2012, 11:35:51 PM »
In a book "The WEather Observers Handbook" I am reading it is suggested that a budget station, well sited (and by implication, well housed, can provide useful data. This station may be cheap, and may not be strong by Davis standards, but its a start. How many of us started with a pro SLR camera, or telescope or two wheeler bike. If we can get these users on board and recording data, contributing to the Forum and being interested in the weather is that not we should be aiming for? My first station was created when computers had not even been thought of.
I would say go for it. There are so many folk with budget stations out there, especially in non US countries, because they cannot afford the astronomical  price of Davis kit. I still cannot justify it myself, with little change out of $2500 to get the equivalent of my current station with Oregon.
Perhaps a codecil could be included for these budget stations about siting and exposure as it is so much more critical with them than with Davis kit. Perhaps the mechanically minded Forum members might even show us how to build a small screen or shelter for the temperature sensors?
Go for it Stu, if you can find the time, but then, how often does it rain in Scotland????

Best wishes

Mike

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Re: Fine Offset
« Reply #11 on: August 28, 2012, 10:25:52 PM »
Howdy Mike and WeatherCat fans,

In a book "The WEather Observers Handbook" I am reading it is suggested that a budget station, well sited (and by implication, well housed, can provide useful data. This station may be cheap, and may not be strong by Davis standards, but its a start.

Definitely agreed and very well said Mike!  [tup]

Lots of folks without a lot of cash aren't short of enthusiasm and that would be healthy for the WeatherCat community.

Cheers, Edouard  [cheers1]

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Re: Fine Offset
« Reply #12 on: August 28, 2012, 11:08:44 PM »
Ok, it's up. Supports WH1080 and WH2080, no 3080 support at the moment.

I've been able to pull lots of stuff out of it that isn't available on the console - all in, I've managed to get 20 channels out of it.
Additions to the output from the console include: rain rate, daily rain, 10 minute average wind direction, 4 gust periods and directions (1, 5, 10 and 15 minutes) , dew point and wind chill. Overall, I'm very pleased with the driver.

I'm going to leave it run for a bit to see how it deals with comms issues (should there be any) - so far it's over a 2000 good packets with no errors.

The station is a bit weird in its interface and there are pitfalls when reading the data that can result in bizarre values being recorded. I've implemented an atomic read (to ensure the data isn't being changed by the hardware during the read) followed by a two stage check to validate the data before we pass it on to WeatherCat - this seems to be giving good results.

Stuff missing at the moment include logger support, pressure correction and 3080 support - I'll leave these until I'm happy with the stability and it looks like it's going to be usable. 3080 support may have to wait until I can get my hands on one so I can look at what it's doing whilst running under Virtual Box and the supplied software.

If all goes well, I should have some web pages being driven from it up in the next few days.

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Re: Fine Offset
« Reply #13 on: August 29, 2012, 12:42:51 PM »
Cool! THis is going to generate a lot of interest. THe only downside I see is cost. A $79 application to use a $400-1200 station is fine, $79 to run a $99 station might be harder to swallow until the new user tries WC and finds how easy it is to use and how configurable it is.

Thanks for starting on this,
Steve

Just a clarification on the price, WeatherCat currently costs $64.95 in US dollars.

Stu.

Steve

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Re: Fine Offset
« Reply #14 on: August 29, 2012, 02:11:09 PM »
Ooops! Sorry, and thanks for the clarification.
Steve
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