Author Topic: How to make a Cheap - Rain Gauge Resolution Modification to your OS hardware.  (Read 52340 times)

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Offline Downlinerz2

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Re: How to make a Cheap - Rain Gauge Resolution Modification to your OS hardware.
« Reply #50 on: September 09, 2009, 04:44:41 PM »
Strgazr27,
    Looks really good =D>!  I am probably going to have to wait until next spring.  There is a small chance might get it done the end of October.  Can't wait to get it done!!!

Offline stevebrtx

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Re: How to make a Cheap - Rain Gauge Resolution Modification to your OS hardware.
« Reply #51 on: September 21, 2009, 10:38:33 AM »
My funnel is waiting in TX, I won't get it up until late Oct so will miss this rainy season, but I'll be ready for next year when it starts in June for sure. I even opted for a little rain gauge shelf to go with the new OS200. I'll have to see how to stabilize the unit to be sure it doesn't wiggle, currently mine is "attached" to the solar collector and when the pool kicks in it vibrates enough to cause the buckets to tip if there is residual water from a previous shower so you get a .04" bump at 11am when it's sunny bright even though the rain quit at 4am.

Offline mblanton

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I've got the paint on my funnel drying. Can anyone tell me specifically which files in my WMR-968 console and VWS software do I need to edit?
Mark Blanton
Ham Operator WC5M
Assistant Emergency Coordinator for Ouachita Parish, Louisiana ARES
National Traffic System Official Relay Station
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Offline Downlinerz2

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   I think all of the changes are noted on the first page of this thread. You just have to put a gain into the VWS.  Amount depends on the size of your funnel.
     MG

Offline mblanton

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I meant which files do you have to edit after you make the change?  I thought someone said that editing the gain would change the rainfall values stored somewhere??? Which files contain the rainfall data that has to be edited??

Mark Blanton
Ham Operator WC5M
Assistant Emergency Coordinator for Ouachita Parish, Louisiana ARES
National Traffic System Official Relay Station
NWS Certified Skywarn Storm Spotter


Offline mackbig

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no files to edit.  You input a gain in calibration.  See post on, it has all the math and screen caps where to enter the gain number.
Andrew


I meant which files do you have to edit after you make the change?  I thought someone said that editing the gain would change the rainfall values stored somewhere??? Which files contain the rainfall data that has to be edited??



Andrew - Davis VP2+ 6163, serial weatherlink, wireless anemometer, running Weather Display.  Boltek PCI Stormtracker, Astrogenic Nexstorm, Strikestar - UNI, CWOP CW8618, GrLevel3, (Station 2 OS WMR968, VWS 13.01p09), Windows 7-64

Offline sam2004gp

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I've got the paint on my funnel drying. Can anyone tell me specifically which files in my WMR-968 console and VWS software do I need to edit?

I hope your paint is for plastic.  We had a 30 mph wind that stripped most of my paint off a few days ago.  I bought plastic paint last night, and I am going to scuff up the surface a bit.  My only problem is they are calling for rain this weekend.  I would like a good 2 days of clear weather so I can remove it from it's mount, clean it up, paint it, dry time, and re-install.
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Offline sam2004gp

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I meant which files do you have to edit after you make the change?  I thought someone said that editing the gain would change the rainfall values stored somewhere??? Which files contain the rainfall data that has to be edited??



If he changes his gain, mid year, it will mess up his total rain number.  

Thus do it like this.
1. Write-down your rain amount for the year so far, and the month so far.
2. Enter your new gain value.
3. Observe what VWS "thinks" is now your new rainfall for the year value.
4. Your Offset correction will be the Actual rain number (1) minus the number in (3) above.
5.  Go to your calibration settings.  If your rain "offset" is 0.00 then enter the number from 4.
6.  If your rain "offset" is NOT 0.00 then take what the current number and add 4 to it.  What you are wanting to do is basically get VWS rainfall total number back to where it was before you changed the gain.  
7.  Give things a minute to settle then observe your rainfall for the month amount.  If this is incorrect, then go and adjust the month and day value in the "rainfall montly/yearly" settings menu to reflect what they should be.
8.  After this process is complete.  Shutdown VWS, and restart it.  Don't be alarmed if VWS's graphs/gauges for rain seem goofy.  These will clear up after the information scrolls off of the appropriate display.  The important thing here is again that your yearly rain and monthly rain match what they were from before, and you have your new gain factor entered in as well.

Another word of advice for the end of the year.
At 11.58PM on Dec 31 shut down VWS.  Restart VWS at 12:02am on Jan 1st.  Wait 5 minutes, then Shutdown VWS again.  On your OS WMR968 reset/clear the memory for your rainfall total.  Restart VWS, go to the calibration settings and change your offset to "0.00".  Allow VWS to settle, shutdown one more time and restart it.   ----  This will effectively start your rain totals over for the new year without destroying rainfall total in the data files from the old year.  Plus if you need to ever adjust the values for rain gauge maintenance reasons in the new year, it will make it easier to do the math since the rainfall number in your OS WMR-968 will be a little easier to understand then.
« Last Edit: October 09, 2009, 09:13:16 AM by sam2004gp »
SAM --->>> http://www.mountcrawfordweather.org
OS WMR-968 with a Dedicated PWS Weather Computer running VWS v13.01 p09


Offline killwilly

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Thanks for your last post Sam. I think your year end advise is useful, whether you have the modification or not.  =D>

Alan.
Alan

Offline sam2004gp

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Thanks for your last post Sam. I think your year end advise is useful, whether you have the modification or not.  =D>

Alan.
No problem Alan. 
Rainfall entry in VWS, I think is the most confussing thing about the whole program.  It's taken me about 2 years, but I just about got it figured out. :-)   
.....I think.  #-o ](*,)
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Offline mblanton

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I got a can of Krylon brand Gloss White spray paint.  It is supposed to be for plastic, wood, or metal and indoor/outdoor use....will see how well it holds up.  I may cover that with a clear coat for added protection.  I found an aluminum funnel at my local hardware store that was exactly 8 inches.  If I've done the math correctly that works out to a gain of 0.2346 and each bucket tip will add .0093847 inches of rain to my total. Since CWOP only tracks rain to the nearest .01 inch is there any point in increasing the precision of the rain measurement number recorded in my VWS software to 3 or 4 digits?
Mark Blanton
Ham Operator WC5M
Assistant Emergency Coordinator for Ouachita Parish, Louisiana ARES
National Traffic System Official Relay Station
NWS Certified Skywarn Storm Spotter


Offline sam2004gp

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No need to change the precision settings, they are actually for display purposes only.  The precise number will still be there. VWS will just round the numbers for you anyways when displaying it and using the regular precision settings. 

When entering your gain number into VWS round up to the TWO decimal places.  I calculated my potential for "rounding errors" in allowing VWS do this and over the year it did not make much of a difference.

Take a look at this post again.  http://www.wxforum.net/index.php?topic=2738.msg21371#msg21371
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Offline stevebrtx

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Finally got my 8" funnel retrieved from TX, I got the one from the beer equip supply and it's great with a built in screen and a couple of "ears" at the top rim which are convenient for stabilizing it back to the support pole. Even popped for a shelf for the new gauge and installed it yesterday, we had enough drizzle to test the .01" increment and it works, now we'll be ready for the rainy season next June.

http://www.homebrewmart.com/ and search for "funnel". It's $5.95 plus shipping.
« Last Edit: November 07, 2009, 10:23:44 AM by stevebrtx »

Offline sam2004gp

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Congrats, it's the best cheapest mod you can do.  =D> \:D/
SAM --->>> http://www.mountcrawfordweather.org
OS WMR-968 with a Dedicated PWS Weather Computer running VWS v13.01 p09


Offline killwilly

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Sam.

Towards the end of your instructions for the rain gauge conversion, you show a photograph of the calibration box in VWS. You have highlighted in red where to install the gain calculation. Next to that there is a figure of 4.14 in the offset box. At the end of year when you shut down VWS and reset the base station, do you have to remove that offset figure, or is it automatically zeroed?

Alan.
Alan

Offline sam2004gp

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Yes, at the end of the year if you reset your base station you will also have to change that offset value back to zero, manually.   I usually shut down everything at 11:50PM New Years Eve, backup the VWS folder, Reset the console, relaunch VWS at about 12:05AM New Years, clear the offset, shut down VWS, and restart VWS one more time.  Then all should be good.
SAM --->>> http://www.mountcrawfordweather.org
OS WMR-968 with a Dedicated PWS Weather Computer running VWS v13.01 p09


Offline killwilly

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Yes, at the end of the year if you reset your base station you will also have to change that offset value back to zero, manually.   I usually shut down everything at 11:50PM New Years Eve, backup the VWS folder, Reset the console, relaunch VWS at about 12:05AM New Years, clear the offset, shut down VWS, and restart VWS one more time.  Then all should be good.

Thank you kind sir.  :grin:

Alan.
Alan

Offline pvw

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At the risk of resurrecting an old thread, I just have to say that this mod has worked out quite well for me.  Over the last couple of precipitation events I've had, my manually collected CoCoRahs readings and the OS bucket gauge have tracked very closely, to 1/100 of an inch.
Better living and lower productivity through the use of technology.

Offline sam2004gp

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I am glad people are still finding it useful.
SAM --->>> http://www.mountcrawfordweather.org
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Offline skysummit

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Thanks for resurrecting this thread!  This may be something to do over the coming weekends while our weather is quiet down here.
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Offline pvw

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Well, Yesterday (Recorded at 7:00am this morning), I recored 3.3 inches of snow with a moisture content of .24".

It had stopped snowing by the time I took my CoCoRahs reading.

Since it was below freezing last night and this morning, of course the OS didn't record anything until the melt started today. 

It just apparently finished the melt and my OS Rain gauge recored .24" of rain...

Couldn't be happier with this resolution mod...
Better living and lower productivity through the use of technology.

Offline aweatherguy

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In my opinion, the WGR800 rain gauge is probably the best piece of equipment in the OS sensor lineup. I've done a lot of testing at different simulated rainfall rates, and it delivers surprisingly consistent and accurate results for rates as high as 4 inches/hour (that's with the funnel attachment). I frequently compare my gauge with a Stratus manual gauge (the CoCoRHaS unit) and it always comes out within +-1%, +-0.01 inch.

Offline BaronV

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Since the gain measurements are only implemented on the PC dosent that mean that the rainfall measurements displayed on the console will now be completely wrong?

Alternatively since increasing the funnel size simply increases the amount of water falling into the rain gauge, not how much water is required to tip the bucket, shouldnt it mean that actually you dont need to implement the gain setting at all since the bucket will just tip more often?

Offline sam2004gp

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Yes the console is no longer accurate, but most folks on here use a computer to display their data.

 As for the funnel change.  By adding it, you are increasing the collection area by 4-fold, therefore the lower gain takes up for that.  But the Original OS gauge would only had an accuracy of .04 on it's original size bucket, so by increasing the collection area and reducing the gain proportionatly, mathematically you increase the accuracy of the gauge to read within .01.  I have been using this method since this thread was started and compared with other gauges and is very accurate even during storm downpour situations.

So basically if you increase the collection by 4, and yet it rains .01 it will read in VWS as .04 unless you implement a gain of .25 to bring it back to the .01.
« Last Edit: July 03, 2011, 10:53:58 PM by sam2004gp »
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Offline BaronV

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okay I think I understand now. Its a simple case of multiply and divide. What I dont get though is dosent the bucket tip when about 0.4 inches (average) rain fall into it? Or is it saying that an equivalent of 0.4 inches of rain have tipped.