Tom,

The data protocol of their (not so cheap) data-loggers is publiced by 
Davis, but I know from first hand that the raw data the sensors send to the 
console is not public. I have put a lot of time in decoding the signals 
(among others) and still we don’t know the full protocol yet.

Luc

On Sunday, 17 May 2020 21:34:27 UTC-3, Tom Keffer wrote:
>
> Just to correct the record, the Vantage protocol was not reverse 
> engineered. They are one of the few vendors who have published their 
> protocol 
> <https://support.davisinstruments.com/article/rbzgl0rh6k-vantage-pro-pro-2-and-vue-communications-reference-2-6-1-any-os>,
>  
> and have for many years.
>
> On Sun, May 17, 2020 at 5:13 PM Greg Troxel <[email protected] <javascript:>> 
> wrote:
>
>> "'Ben Luria' via weewx-user" <[email protected] <javascript:>> 
>> writes:
>>
>> > apologies if this topic came up before or in case I am off-topic here. 
>> I'm 
>> > toying with SDR and home automation on a Raspberry Pi and would like to 
>> add 
>> > weather data via WeeWX and a weather station. Is there any particular 
>> brand 
>> > / model I should go for or maybe avoid? Am looking for something solar 
>> > powered optimally, but that is not a must.
>>
>> You put "open" in quotes, which means that I don't know what you mean by
>> that word :-)
>>
>> There are a few things you could mean:
>>
>>   1) well-understood interfaces and existing drivers so that you can get
>>   at the weather data and use it, and not have problems due to closed
>>   interfaces
>>
>>   2) open protocol, or perhaps reverse-engineered protocols, for the
>>   sensor suite (outside part) to talk to the console (inside, that you
>>   look at, and that usually is interfaced to a computer), so that you
>>   can sniff it with an SDR instead of using the console receiver.
>>
>>   3) being able to get at the weather data locally, without the device
>>   talking to some cloud service (not under your control, subject to the
>>   company stopping it, and likely run with proprietary software)
>>
>>   3A) separately from transport via cloud, can the local station produce
>>   observations by itself, or does it need a (perhaps implemented with
>>   proprietary software) cloud service to do that?
>>
>>   4) firmware/software for the weather station equipment being open source
>>
>>   5) an open hardware design for the station, even if it uses proprietary
>>   chips
>>
>>   6) full-on open, meaning open licenses for all silicon in the station,
>>   including CPUs and sensors, which leads you to RISC-V and for
>>   temp/humidity I'm really not sure what.
>>
>>
>> You mentioned home automation, so I would recommend you check out the
>> mqtt extension, which is I think what most use to bridge weewx data into
>> an automation system (such as Home Assistant, which is the natural
>> choice for weewx fans, being open source and python).
>>   https://github.com/weewx/weewx/wiki/mqtt
>>
>>
>> For 1, there are lots of choices, and basically you should look at what
>> weewx supports.
>>
>> For 2, I am not really aware of anything open, except for build-your-own
>> kinds of stations.  But maybe weatherflow is UDP over IP and counts
>> here.  The Davis VP2 protocol has been reverse engineered and there is
>> rtldavis.  However, the Davis datalogger/interface in the console has
>> the really nice property that when your computer goes down, it keeps
>> storing data, and then when you straighten out your computer from the
>> botched upgrade, or you get power back, weewx reads the data and your
>> historical record is 100% fine, as if you never went down.   So I don't
>> really want to get my data with an SDR on a unix computer, even though
>> I'd like to try that, because I really like it that I haven't lost data
>> the probably 6 times I've had an issue in about 2.5 years.
>>
>> For 3, Davis is fine, and some acurite setups have local USB.  Various
>> other systems have "interceptor" drivers that snoop the data going to
>> the cloud, and I have the impression that sometimes people fetch their
>> own data back from the cloud because that's all they can do.
>>
>> For 3a, note Vince's comments about weatherflow and rain.  (I think
>> weatherflow is really interesting and don't mean to knock them.  I just
>> find the notion that you don't know how much rain you got without the
>> internet quite curious.  On the other hand sometimes with Davis it rains
>> and you conclude from the readings that you have a bird's nest, wasp's
>> nest or pine needles in your rain collector or blocking the tipping
>> bucket from tipping.)
>>
>> For 4, and even more so for 5, I'm not aware of any contenders, other
>> than build-your-own with arduino and e.g. i2c sensors.  But this is
>> very interesting and may qualify:
>>   
>> https://www.tinkerforge.com/en/doc/Kits/WeatherStation/WeatherStation.html
>>   https://www.tinkerforge.com/en/shop/bricklets/sensors.html
>> However, I don't see rain and wind.
>>
>> For 6, my impresssion is that I will be viewed as crazy just for
>> bringing it up.
>>
>>
>> That leaves you with all the other considerations, which is that Davis
>> is expensive but otherwise viewed favorably by most, and that various
>> cheap stations are cheap and tend to fail.  And weatherflow seems to
>> turn everyone who plays with one into a fan, which is a very positive
>> comment.
>>
>>
>> There are surely DIY/maker projects out there to do rain gauges and
>> maybe wind.  Temp is fairly easy, but you need to build a radiation
>> shield.  So I'd say this is for "my hobby is building a weather station
>> from parts" vs "I want to get weather data into my home assistant setup
>> and I don't want anything too egregious".
>>
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>>
>

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