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This rain sensor is what I have always been looking for

Discussion of this sensor and its uses
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jpsc
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This rain sensor is what I have always been looking for

Post by jpsc » Tue 17 Jul 2012 1:20 pm

I have always been frustrated by seeing rain but having no trips from the tipping bucket, first from my Oregon WM918 and then from a WMR928NX. In particular I knew that a short shower on a warm day would partially fill the bucket, and then evaporate before the next contribution, leading to missed tips and under reporting.

The Hydreon never misses a drop, and whilst you can argue about linearity and repeatability, its performance when the rain starts and stops is the key for me. I have it set as tipping bucket with 0.01 mm bucket, and looking at the debug log it is great to see the odd bucket tip over the space of an hour adding up to something that eventually registers (ie more than 0.1mm), whilst the station tipping bucket remains silent for days - although not so much of that recently. On the subject of missed RG11 tips, I'm setting up a Delphi program to read the RS232 out (might even be able to route it to a second serial port in addition to the Cumulus input), I think there may be an absolute tip count in there, but need a description of all the registers from Hydreon.

Steve, when you are happy with the performance, I presume you will provide the same full set of webtags for the RG11 as you give for the weatherstation sensor. Can you provide an option to send the new sensor readings to Weather Underground, etc instead of the station rain readings? Also (I'm greedy) would it be possible to set the <#IsRaining> tag for tipping bucket RG11s, say if there was a bucket tip in the last 5 minutes? or better still allow the setting of a rain amount and a time so that we can decide what constitutes rain.

Really impressed with Cumulus, it keeps getting better and better. I'm glad I switched from FreeWX.
John Cooper

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http://weather.mountpleasanthouse.uk

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Re: This rain sensor is what I have always been looking for

Post by steve » Tue 17 Jul 2012 1:37 pm

jpsc wrote:Steve, when you are happy with the performance, I presume you will provide the same full set of webtags for the RG11 as you give for the weatherstation sensor. Can you provide an option to send the new sensor readings to Weather Underground, etc instead of the station rain readings? Also (I'm greedy) would it be possible to set the <#IsRaining> tag for tipping bucket RG11s, say if there was a bucket tip in the last 5 minutes? or better still allow the setting of a rain amount and a time so that we can decide what constitutes rain.
Yes, at some point I can look at adding more support for the RG11 in terms of web tags etc; but there are about 80 existing rainfall web tags, so it's no small task to provide equivalents for all of them.
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Re: This rain sensor is what I have always been looking for

Post by AllyCat » Tue 17 Jul 2012 2:25 pm

Hi,

Isn't the main point of the Hydreon that it can replace a conventional tipping bucket sensor, so all the webtags are already available? Of course it's "nice" to have separate data channels, but that can apply to all the sensors used in Cumulus, and Steve has (IMHO rightly) been reluctant to add those.

With the current price of FO kits (less than a Hydreon!) and the fact that they make different frequency/protocol systems it's quite possible to run two complete systems, except for the "bottleneck" of USB. Something that's possible with good ol' COM ports. :o

Concerning the additional processing of Hydreon data, "watch this space". ;)

Cheers, Alan.

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Re: This rain sensor is what I have always been looking for

Post by steve » Tue 17 Jul 2012 2:46 pm

I have to admit that in adding support for the RG11 it wasn't really my intention to go all the way and give them equal status to the station's rain gauge; I assumed that most people would be using them for the 'It's raining' function, rather than as an additional rain counter. It does raise the question of why you would want two separate rain gauges - which one do you believe?
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Re: This rain sensor is what I have always been looking for

Post by jpsc » Wed 18 Jul 2012 8:08 pm

AllyCat wrote:Hi,

Isn't the main point of the Hydreon that it can replace a conventional tipping bucket sensor, so all the webtags are already available? Of course it's "nice" to have separate data channels, but that can apply to all the sensors used in Cumulus, and Steve has (IMHO rightly) been reluctant to add those.
Yes, my first thought was to replace my Oregon reed switch with a connection to the RG11, but Steve was there with support straight away, saving me climbing up to mess with the sensor.
AllyCat wrote: Concerning the additional processing of Hydreon data, "watch this space". ;)
Do you have an explanation of all the RS232 reported registers? I was going to write to rainsensors to ask.
John Cooper

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Re: This rain sensor is what I have always been looking for

Post by jpsc » Wed 18 Jul 2012 8:12 pm

steve wrote:Yes, at some point I can look at adding more support for the RG11 in terms of web tags etc; but there are about 80 existing rainfall web tags, so it's no small task to provide equivalents for all of them.
Understood. Very happy with pace of support, was expecting to have to do it myself, so anything you do is a bonus.
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Re: This rain sensor is what I have always been looking for

Post by AllyCat » Wed 18 Jul 2012 8:59 pm

jpsc wrote:Do you have an explanation of all the RS232 reported registers? I was going to write to rainsensors to ask.
Hi,

No, apart from the rather cryptic protocol details document linked on Hydreon's website. The RGBits "flags" register and some of the "Slowly Transmitted" bytes look of most interest. One of the functions of my current "project" will be to "digest" the RS232 stream of data (some values appear to be permanently stuck at zero) and forward any useful values.

I also have a few questions concerning the interface which I might ask Hydreon (if I can't work them out for myself) but as the RS232 document says "We are making this available on an “as is” basis. .... and we offer no support beyond this document" I didn't think it reasonable to ask specifically about the data itself.

Cheers, Alan.

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Re: This rain sensor is what I have always been looking for

Post by duke » Thu 19 Jul 2012 4:51 am

I didn't think it reasonable to ask specifically about the data itself.
Doesn't do any harm to ask. They can only say no ;) .
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