Topic: Looking for high quality, open protocol weather sensors

[cdenney]

I've been running the WeatherRack2 weather station that you used to be able to buy from SwitchDocLabs (https://www.switchdoc.com/, now discontinued). While I've been extremely happy with it's openness/hackability (I'm running the entire thing locally), but I have not been very happy with the quality of the sensors. I've also been pretty unhappy with the annoyingness of the wireless.

I wanted to upgrade my setup, while maintaining the 100% self hosted/local-ness of my setup. To that end, I was looking for either individual sensors that communicate in a well documented way, or a weather station that does so. I'd also like to switch to wired instead of wireless. It's more reliable and I am able to run cabling to the sensors/station.

Davis Instruments seems to have it's protocol understood (see https://www.wxforum.net/index.php?topic=24056.msg330498#msg330498 and https://github.com/dekay/im-me/blob/master/pocketwx/src/protocol.txt), but I'll be honest that I'm a bit skeptical of their pricing ($500 for wind, rain, and temp + hum, another $500 to add solar radiation + UV, for the cabled Vantage Pro 2). I'm willing to pay for quality, and if that is legitimately how much quality sensors cost, then fine; buy once cry once as they say. But I'm not a researcher, I'm a hobbyist, and while I'd like decent accuracy, I think that Davis might be slightly overkill for my needs (although I'm open to being convinced it's not)

So that was a bit rambly. To try and sum up what I'm looking for:

• Rain guage
• Wind Speed + direction
• Temp + humidity
• Solar radition + UV
• Preferred wired instead of wireless
• ability to interface the sensors/station directly with something like an Arduino or Raspberry Pi

I'm fine either hodge-podging this together by getting individual sensors or getting a combined rack.

[johnd]

I guess that you will get a bunch of suggestion, but my take in a nutshell is:

• If you want cheap then it will be wireless and Chinese. Off the top of my head I can't think of another cheaper and integrated source of all those sensors in cabled form except Davis
• There are plenty of other sources of high-end sensors like Campbell Scientific and Vaisala to name but two, but considerably more expensive than Davis
• Consider whether or not you want the UV sensor - it is the most expensive sensor of all. But if you do want UV and decide on Davis then definitely cheapest to buy it upfront in a package. Beware of cheap sensors that claim to measure UV - typically they are measuring sunlight intensity in general and guessing at a value for UV.

[Mattk]

A general comment then would be if there is skepticism regards Davis pricing and might be slightly overkill then there is not much point in putting forward options they would obviously be way over the top in just about all aspects

[cdenney]

I guess that you will get a bunch of suggestion, but my take in a nutshell is:

• If you want cheap then it will be wireless and Chinese. Off the top of my head I can't think of another cheaper and integrated source of all those sensors in cabled form except Davis
• There are plenty of other sources of high-end sensors like Campbell Scientific and Vaisala to name but two, but considerably more expensive than Davis
• Consider whether or not you want the UV sensor - it is the most expensive sensor of all. But if you do want UV and decide on Davis then definitely cheapest to buy it upfront in a package. Beware of cheap sensors that claim to measure UV - typically they are measuring sunlight intensity in general and guessing at a value for UV.

That's a good point about the UV. I don't really care that much about it on it's own (although I do really want a general light sensor), but since I'm running my own software anyways, light sensors are probably the single easiest to find form hobbyist electronics shops.

Davis for the main package and some cheap light sensor might be my best option.

[BfdWx]

Think about longevity too. A few years ago my long running Davis started to fail. I could have replaced boards, sensors etc. but there were new shiny objects out there. I went for one of them, it was an all in one solution, even offered lightning detection. Well, I went through two in two years, yes they were under warranty and the company sent me new ones but when the third one failed I was done! Went back to Davis and without a doubt they are not the cheapest out there but based on my previous experience I am confident Davis will have a nice long life in my backyard.

[zeppline]

It all depends where you live, if you live north you don't need UV but if you live the southwest and the UV is14 the sunburn time is 10 minutes. UV sensors are about $400.00 dollars. The Davis ones last about 8 years. My Rainwise UV lasted 2.5 years. replaced once and now they discontinued. Looking for a replacement weather station. 

[MaineWaterLovers]

Do the statements about Davis durability/reliability extend across their products? Not just the Vantage Pro2 stuff? Thinking specifically of the Vue.

[zeppline]

I only know about Vantage Pro2, being that far north I would save my money.

[southpawranch]

I am a 30 year now retired IT veteran in the cooperative utility industry. I maintained Davis Vantage Pro2 weather stations in all of our substations both wired and wireless. Now retired, I am a 1st responder for the Tarpley Volunteer Fire Department where I live and maintain 7 Davis weather stations across our service territory. That said-

Davis is the best in the prosumer market for accuracy and long term stability. I have stations still rocking along after more than a decade. Repairs are usually housing issues from the plastics degrading from sun damage after year 7-8 with the occasional sensor giving out on very rare occasions. Wireless connectivity is rock solid with multiple wired options for the original Vantage Pro2 Console. There are countless third party software solutions for gathering and reporting data for the original Vantage Pro2 console. I rank Davis support up there with my own coming from a missions critical environment providing my user base with electricity. For me Davis was my only choice. All the point and click, single solution options out there are fine for the hobbyist who's curious about weather and wants more than a plastic rain gauge but in my world they won't hold up for a multitude of reasons.

Unfortunately Davis has dropped support for the original Vantage Pro2 console and software releasing the new Weatherlink Console which I have 2 in service and currently testing. The back end data collection and stability is all still there, sort of. However, the ability to harvest your own data your own chosen way has been taken away and is now cloud based with you guessed it, a subscription. The console of course is real time but the cloud reporting is only every 5 minutes and current view only for the free account. Everything else costs extra which is very disappointing. Davis is now catering to the point and click idiots who need pretty colors which is fine. But they are making a mistake monetizing historics forcing me to pay by taking the ability for me to harvest my own data away.

[johnd]

Unfortunately Davis has dropped support for the original Vantage Pro2 console and software..

Davis have not stopped support for the 6312 VP2 console, but have ceased manufacturing it (in part because the console display panel became impossible to source at any reasonable price apparently). The old Windows software is still available but no longer being developed, having been superseded by the cloud version.

...releasing the new Weatherlink Console which I have 2 in service and currently testing. The back end data collection and stability is all still there, sort of. However, the ability to harvest your own data your own chosen way has been taken away and is now cloud based with you guessed it, a subscription.

That is true specifically with reference to the new 6313 VP2 console. But local data handling is still perfectly possible in the VP2 range with either the Weatherlink Live unit or an Envoy unit plus a legacy logger. OK, that functionality is not currently available in a single display console, but the local data management functionality is still very much available.

[southpawranch]

You can not harvest data with the new Weatherlink Console locally nor port your historics from the previous Vantage Pro2. You end up having to set up a new account on the Davis cloud... Big oversight

[johnd]

You can not harvest data with the new Weatherlink Console locally

Correct, and as I agreed. But WLL or Envoy + logger are there as alternative option for local data handling.

nor port your historics from the previous Vantage Pro2.

That option is likely to be available before too long I suspect

You end up having to set up a new account on the Davis cloud... Big oversight

Difficult to see it ever being easily possible to convert a legacy type of station (eg uploads via a logger) directly into the modern type (eg Weatherlink Live or 6313 console) at weatherlink.com. AFAIK the associated data structures in the cloud are very different. Technically, it must be possible in theory of course, but I'll be surprised if Davis ever consider the work required to be worth the effort. But maybe I'll be proved wrong.

[vinceskahan]

forcing me to pay by taking the ability for me to harvest my own data away.

For an IT veteran, you can get there for under $70 or so with weewx, the rtl_davis driver, and an inexpensive SDR antenna if you just need outside measurements from the ISS.  If you need inside temp+humidity+pressure you'd have to cobble your own together with a breadboard or maybe a cheap ecowitt solution feeding MQTT perhaps.

But yeah.  Subscriptions and cloud.  Ugh.

[TheBushPilot]

I know I may be a little late to the party, but if the OP is looking for something modular, open source, and wired: have you considered the second-hand market research grade equipment? Surplus sites and eBay have a trove of instruments for pennies on the dollar. This path is pretty involved however so it may not be the option if you want plug and play.

Retired Campbell Scientific Data Loggers offer a cost effective and flexible platform despite being somewhat dated. Given you are looking for a hobby grade station, "good enough" tolerances suffice. Granted the programming language has a bit of a learning curve (Windows DOS era) but once acquainted, you can do a lot with them.

Most of the instruments found used are (from my experience) pulled from service prior to their expiration. You can typically match the price of a fully loaded Davis VP2 with that of a "starter" mesonet station using commercial grade components if done strategically.

If I were in your shoes and was looking to get something cost effective yet robust in the long term, I would consider the following - generally adhering to your requirements:

Wind Speed and Direction: R. M. Young 05103 Wind Monitor
- These can be found for around $150 to $400, anticipate bearing replacement as most are old stock surplus used. Propeller shaft bearings typically run $11 each. Vertical shaft bearings while rare needing replacement go for around $40 each. Once replaced you probably will not need to replace them during the lifespan of the instrument.

Temperature and Relative Humidity: Vaisala HMP155
- Can be found for $200 to $500, potentially need reprogramming from RS-485 to voltage 0-1V output per T and RH channel output. This only requires a USB to RS-485 converter and following the manual. These are pretty flagship for general use.

Barometric Pressure: Any R. M. Young/Vaisala/Setra Systems absolute barometric pressure transducers
- Most of these are compatible with Campbell Scientific data loggers assuming they have 0-1V/0-2.5V/0-5V or serial RS-232 configurable output. They can be found for around $50 to $300. I know this isn't in your list but sometimes a steal can be had.

Precipitation: RainWise 8" Tipping Bucket Rain Gauge
- $70 and generally accepted as a very good rain gauge. I've had success and would recommend using the Peet Bros TB rain gauge mounting kit for $50. Very well built and good quality.

Solar Radiation and UV: Spectrum Tech SolRad and UV sensors
- I saw someone else using these from the forum which can be found here:
WxForum Thread
Light Sensors
Both listed for around $300.

Or alternatively if UV is not required, picking up a new Apogee Instruments SP-110 self powered solar radiation sensor for $250.

Li-Cor sensors are also able to be found for around $100 or so.

Data Logging: Campbell Scientific CR23X
- These can be found for around $100 to $350. Completely configurable and compatible with 99% of instruments on the market, and compatible with all of the aforementioned sensors.

I recommend this logger over others available because of the readily available RS-232 port. The CS I/O port is Campbell's proprietary communication protocol that requires an SC32B. These go for around $120 but are not required given the already available standard serial port. This is required for programming and data collection.

Microcontroller: Any board with WiFi and serial communication capability (0-5V logic levels).
- While the CR23X is archaic, it still can communicate with the microcontroller.

You can program the data logger to output a serial string of the measured data values that can be read by the microcontroller, parsed into usable values, and uploaded to a database on a web server at a user adjustable rate. The data logger can also save the data locally in coarser temporal resolution for long term records and redundancy.


Hopefully the information I provided helps the OP or anyone looking to be smart about their next weather station and are tired of being stuck in the prosumer product ecosytem. I know this was a pretty surface level post but ff there are any other details anyone wants me to go into I am more than happy to elaborate. I can here or PM's open.

Best of luck


Cheers