Homebuilt Serial Interface for Davis stations

[af4ex]

Hello,
Weather newbie here, just got my first wx station, Davis Vantage VUE, which is really nice. I'm an amateur radio operator and am sending my reports to the ham APRS/CWOP network using Cumulus. I keep the console downstairs in the family room (for everyone to enjoy), but run Cumulus and other APRS software (APRSISCE) upstairs in my hamshack. So I have a wireless link that I designed my self which uses a pair of XBee wireless serial modems, plugged directly into the console box and the weather radio (Yes, I know I could do this with WeatherLink/Envoy, but that was too much $$$ for me).

HARDWARE
The hardware details of my serial interface can be seen at WXForum [http://www.wxforum.net/index.php?topic=10721.0 ], but I would be glad to answer questions about it either here or at wxforum.

SOFTWARE
The good news is that my homebuilt interface doesn't seem to require any special software to run, other than a standard serial connection. At least this is true for the two programs I've run so far (Cumulus and WuHu). I think this is mostly due to the excellent API which Davis has very generously made public to facilitate the use of 3rd party software.

I'm able to run the Cumulus monitor program and have enabled the website (http://www.qsl.net/af4ex/wx), both of which seem to run fine via my interface, with the possible exception of the rain history feature. It doesn't seem to 'remember' rain from a week or so ago.

I have a question for Steve. In addition to exposing the API (which resides in the console) the Davis interface ("WeatherLink", which I don't have) also provides some logging capability. Does Cumulus depend in any way on this additional capability?

If so, then perhaps I could write some minimal software of my own to patch in that capability in my homebuilt interface, to make it look more like a "WeatherLink" interface.

I should point out that I'm not trying to compete with Davis here, for whom I have great respect for the quality of their product line. Rather, I've created a "low-cost serial interface" for myself (and those intrepid amateurs not afraid to poke around with a soldering iron). Such a "low-cost" interface seems to be missing from their product line.

Thanks,
John/af4ex

[steve]

Hi John, someone did post a link to your discussion on wxforum a while ago; interesting stuff.

Cumulus does assume that the station has a logger and will attempt to use it by default, but there's a setting to turn off use of the logger. With that set, I can't think of any reason why it shouldn't all work perfectly well, including the rainfall figures, assuming Cumulus is running most of the time (24/7, ideally). If it wasn't running at midnight, in particular, that would definitely cause problems with the daily rainfall totals.

[af4ex]

@cumulus
> Hi John, someone did post a link to your discussion on wxforum a while ago; interesting stuff.

That was me, reporting a problem caused by 'sleep' mode (which is fixed now). Just thought I should re-post here, to bring this homebuilt interface to the attention of your home-building audience, and to get more insights on the software side.

Actually, because of that sleep-mode problem, my station probably went down before midnight on a couple of occasions. For the past few days it's been running pretty solid (except for a Florida-style brownout yesterday). Need to get an UPS before the really nasty Florida weather happens this summer (which is the most interesting weather of course).

[steve]

That was me, reporting a problem caused by 'sleep' mode (which is fixed now).

Ah, right, now I re-read your post I see that; I hadn't appreciated that it was the same interface. Someone else had previously posted a link also!

[hswaters]

Hello,
Weather newbie here, just got my first wx station, Davis Vantage VUE, which is really nice. I'm an amateur radio operator and am sending my reports to the ham APRS/CWOP network using Cumulus. I keep the console downstairs in the family room (for everyone to enjoy), but run Cumulus and other APRS software (APRSISCE) upstairs in my hamshack. So I have a wireless link that I designed my self which uses a pair of XBee wireless serial modems, plugged directly into the console box and the weather radio (Yes, I know I could do this with WeatherLink/Envoy, but that was too much $$$ for me).

HARDWARE
The hardware details of my serial interface can be seen at WXForum [http://www.wxforum.net/index.php?topic=10721.0 ], but I would be glad to answer questions about it either here or at wxforum.

SOFTWARE
The good news is that my homebuilt interface doesn't seem to require any special software to run, other than a standard serial connection. At least this is true for the two programs I've run so far (Cumulus and WuHu). I think this is mostly due to the excellent API which Davis has very generously made public to facilitate the use of 3rd party software.

I'm able to run the Cumulus monitor program and have enabled the website (http://www.qsl.net/af4ex/wx), both of which seem to run fine via my interface, with the possible exception of the rain history feature. It doesn't seem to 'remember' rain from a week or so ago.

I have a question for Steve. In addition to exposing the API (which resides in the console) the Davis interface ("WeatherLink", which I don't have) also provides some logging capability. Does Cumulus depend in any way on this additional capability?

If so, then perhaps I could write some minimal software of my own to patch in that capability in my homebuilt interface, to make it look more like a "WeatherLink" interface.

I should point out that I'm not trying to compete with Davis here, for whom I have great respect for the quality of their product line. Rather, I've created a "low-cost serial interface" for myself (and those intrepid amateurs not afraid to poke around with a soldering iron). Such a "low-cost" interface seems to be missing from their product line.

Thanks,
John/af4ex

John you are a lifesaver. I have spent two days searching for just the information you have provided. When my Davis arrives I will give this a try. I know I will write software for logging and such and I will keep you in mind. It would be wonderful to have a knowledgeable beta tester. I do not sell software so I cannot pay for testing services.

[gemini06720]

...I've created a "low-cost serial interface" for myself (and those intrepid amateurs not afraid to poke around with a soldering iron). Such a "low-cost" interface seems to be missing from their product line.

John, please correct me if I am wrong...

From what I have read, it appears that the interface you have built does not contain any RAM memory, meaning that a program/software must always be connected to the interface (and running) in order to get (pull) the data from the console into the computer.

Whereas the overly expensive Davis Instruments WeatherLink datalogger interface contains some RAM memory where a few hours (or some days) of data is stored - for whenever the program/software is not connected to the interface and not getting (pulling) the data from the console into the computer.

[af4ex]

...
From what I have read, it appears that the interface you have built does not contain any RAM memory, meaning that a program/software must always be connected to the interface (and running) in order to get (pull) the data from the console into the computer.

Whereas the overly expensive Davis Instruments WeatherLink datalogger interface contains some RAM memory where a few hours (or some days) of data is stored - for whenever the program/software is not connected to the interface and not getting (pulling) the data from the console into the computer.

I think you're right, WeatherLink does provide some logging functions that my interface can't support. But it's not a big deal, especically for Cumulus users, because there are many ways to customize weather software to save your data.

I have not run into any problems due to this missing feature. In fact, none of the software that I run seems to notice that it's 'missing'.

[gwynethh]

At http://www.wxforum.net/index.php?topic=10721.0 we have discussed using a Roving Networks XV RN-XV WiFi device for wireless connection to a home network. Works good so far.

[gemini06720]

Thank you very much for the link - I have read about 5 pages so far - but I have saved (to PDF) all 10 pages.

[belfryboy]

Hi, this is my first post over here and thought that I could contribute to the topic,

I have owned and serviced Davis Vantage pro equipment for a number of years, but I got fed up with the archaic looking weatherlink software, and after a lightning strike killed my VP1 I all but gave up. I have since repaired the main station but my logger was stone dead.

I have built the serial interface described over in the WXforum, and then with a little help from another member have enabled the logging part. (I have these for sale if anyone is interested. sorry mods if I have overstepped the mark selling in my first post)

I have used the logger succesfully with Cumulus, but to set the logging interval I either need to go in via a terminal program and use manually typed commands, or use a small application that was written for me to do the same thing.

I have been unable to find a function for setting the interval in Cumulus, and was wondering if this was a feature that may be added in the future.

[steve]

I have been unable to find a function for setting the interval in Cumulus, and was wondering if this was a feature that may be added in the future.

It's possible; I try to avoid writing to stations, I already get people from time to time accusing Cumulus of stopping their station working. It's a slightly different situation with Davis stations, as the interface is documented and any updates are actually done by the Davis DLL anyway - and there's the precedent of setting the clock.

[belfryboy]

Steve,

thanks for the speedy reply to my post. The commands are fairly simple (setper, start etc) and the responses predictable. You are right the the commands are well documented, which certainly made it easy for me to sort out the setup by hand.

BTW I always recommend Cumulus to anyone buying my logger, since it's so user friendly.

Also did you want one of my loggers (gratis of course!) to try out with any software mods that you may choose to do?

[belfryboy]

Edit.

sales based post removed by author

[schlag]

At http://www.wxforum.net/index.php?topic=10721.0 we have discussed using a Roving Networks XV RN-XV WiFi device for wireless connection to a home network. Works good so far.

I used the pinout as described on page 2 of that link and extrapolated the XBee radio setup to use an RN-XV. However, I'm stuck at configuring the RN-XV. I saw your posting where you were able to get it connected.

could you explain how you did the configuration? I think all of my connections are solid but I never see the RN-XV as an ad hoc connection from my laptop running Windows 7. I presume that is default mode although Roving Networks docs say you have to apply 3.3V to another pin.

I'd appreciate any help you can offer.

thanks.