Sunday, January 23, 2011

Davis Weatherlink Software Not Required!!!!

Better start this post off with an admission.  I'm a bonehead.  Last night I was sniffing the SPI traffic on my Davis Vantage Pro 2 Wireless weather station console.  I was seeing traffic back and forth but couldn't figure out any rhyme or reason behind the data.  That is because it isn't there.

The CC1021 chip in this thing talks over two interfaces to the processor.  The SPI interface is used to configure the chip, but the data in and out is over a separate digital interface.  And that interface doesn't seem to be brought out to the expansion connector at the back of the unit.  Oh, bother.  So if I want to sniff the data back and forth between the CPU and the wireless chip, I can't do it from the expansion connector.  And if it takes hacking the hell out of this thing to get that data, then it isn't something I want to do.  So I can spend some time deciphering the register configuration while I wait for my IM-ME to arrive and pick the data up without using the console at all.

But there is more than one way to skin a cat.  I had a suspicion that the Weatherlink Module you can buy from Davis for $100 simply passes the commands from the host PC to the processor in the VP2.  I mentioned a while back that two serial ports are brought out on the expansion port.  Here is a diagram of that port, by the way.

I used my new scope to see if any data was spewing out on either serial port or on PB4, PE2, PE3, or PC4.  Nothing.  But that didn't mean much.  Nothing was asking for data, so nothing was coming out.  And this thing tries to conserve power whenever it can.  So just for grins, let's open up the VP2 firmware that Davis makes available on their web site in a hex editor.

This is the firmware for the base station.  Yet it has the commands that correspond to that of the expansion module that plugs into the back of the VP2 (see this document).  It suggests that if I were to hang a serial port off this thing, I might be able to get some data out of it.  But not just any serial port will do.  The lines on the back of the expansion connector are 0 to 3.3V, whereas a normal serial port might be something like -12V to +12V.  And not a lot of PCs have serial ports anymore.

This, of course, is an easy problem to solve, as most people who have played with an Arduino could tell you.  I have one of these, strapped to work at 3.3V instead of the +5V it comes configured to by default.  If you don't have one already, you can buy this one instead.  It is already set up for 3.3V I/O.
From the Good Guys at Sparkfun

 Next, I had to wire it up to one of the serial ports exposed on the expansion connector, but which one?  Who knows?  I guessed and started off with Serial Port 0.  Here's the hookup.


So that covers the hardware.  Now what about software?  All you need is a terminal program.  If you are on Windows (sucka!), something like Hyperterm will work.  On Linux, I used minicom, crap software that it is.  I guessed that the settings I would need would be the same as that they recommend for the Weatherlink adapter: 19.2 kbaud and 8N1.  Start googling now if you use minicom, because it is so stinking user unfriendly.  Specifically, you'll want to know how to set the port it communicates out of (minicom -s as root, if I remember right).  Remember, dmesg is your friend.  There are two other things you want to do.
  • Turn on your Caps Lock key.  Commands to the Weatherlink dongle are all upper case, and it doesn't seem like it wants to make your life easy and convert for you.
  • Turn on Local Echo in your terminal program, or whatever option it is that echos back the characters that you type.  The Weatherlink dongle doesn't do this, so you'll be typing blind otherwise.
Still with me?  Good, cause we are nearly there.  Type TEST.  You may or may not get a response because the console might have gone to sleep on you to conserve power.  If you don't get anything the first time, try again.  If today is your luck day, it will answer back with TEST.

You are now in complete control of this thing.

Try a few other simple commands. VER prints a version date code, NVER is the version string.  Again, refer to this document for more coolness.  I'm a big fan of STRMON.  Just follow it up at  some point with STRMOFF or it will print this stuff forever.

This is the raw data coming from the outdoor unit, and it shows up every two seconds.  The "7" on Row 1 is the wind speed in miles per hour (it is hex, so a windspeed of 'a' is 10 mph).  Haven't figured out the rest of it yet, but it hardly matters.  The serial protocol document linked just above the picture tells you how to get all the processed data out of the thing you could ever want.  And today I just tripped over these Perl scripts that should do all the lifting for you.  They are written to talk to the Weatherlink dongle, but most if not all of that script should work talking to the unit directly.  Come to think of it, there's a lot of weather station software out there written by enthusiasts that should "just work" with this.  If you try this out, drop a note in the comments.

So there we have it.  No longer do you need to spend $100 on some Weatherlink software that you don't want to get the dongle you do.  All you need is a cheap USB to serial converter, and the rest is up to you.  I still intend to get wireless reception directly from the remote going once my IM-ME shows up in the mail, but that is probably going to take a little time.  Enjoy this for now.


  1. Cool! Yeah, I tried to interface with a Weather Wizard II I bought at Fry's on sale a while back for my APRS station. I even contacted Davis and asked for the interface specs, they responded that I needed to *BUY* the SDK and their dongle! This thing has just been sitting there sensing weather for all these years, data going nowhere. So yesterday, in an idle moment, I googled and to my amazement: there they were...on free! Then I wondered what the hardware interface was and found your stuff! Thanks for sharing... I will see if this works on WW-II as well.

    1. Quick update- I have made a little progress on the Wiz III. The protocol is slightly different than the Vantage, and it appears the interface dongle talks to the console using I2C. If anyone is interested I am posting the progress on my Weatherblog...

    2. Nice work! I'm following your blog now to keep up to date. Good luck!


    3. there's some Wizard III coms stuff on this page:

    4. I have a Vantage Pro (NOT2) that is new to me. So just convert the port with a MAX-232 and I can use it for APRS weather station? Great guns!

  2. I love Fry's.

    If the WWII uses the same dongle as the Vantage Pro console (and I believe it does), then you should be good to go. It would be really nice to hear of somebody else getting this working. Get back to me with how you make out!

  3. What about Vantage Vue - this works for it?
    Can I use this adapter?

  4. СаД

    I don't have a Vantage Vue but it should work since it uses the same hardware adapter as the Vantage Pro 2. The adapter you linked will definitely not work though. As I said on the blog, you need something to adapt USB to 0V and 3.3V levels. This ebay one will convert to levels that are something like +/-12V. That will likely damage your Vue. Be careful.

  5. Thanks, I'll try with FTDI 3.3V.

  6. Sounds good. Let me know how you make out. Just remember when you are connecting up to the expansion port, that you are basically connecting directly to the console's internal processor, with no intermediate interface circuitry to do level or protocol conversion.

  7. I bet the SPI bus is only on the expansion header for this do-hickey:

    I'm curious as to what the other serial interface is for. My assumptions on the 4 IO pins brought to the interface are for the irrigation/alarm control interface Davis sells. (Its just a board with four relays and transistors to drive them and potted, of course.)

    This makes me wonder if any of the dongles have intelligence aside from the one with the Ethernet connection. I am really interested if the APRS dongle is creating the serial string or if the standard firmware is.

    If you don't want to hack your console, I'd suggest finding a wireless Envoy for that purpose. I'll be going that route for my dad's station I'm getting him for his birthday! Let him have the console for his fun.

    Now I'm off to find some 2mm proto board and a 2x10 2mm female header to make my $10 WeatherLink dongle! =D

  8. Awesome site btw. Trying to find any decent hacks on the Vantage is like finding water in a desert.

    You guys ever had a play with the WeatherLinkIP SPI to Ethernet? I've got one or order. It shouldn't be too hard to mod.

  9. Thanks. I've not played with WeatherLinkIP, but let me know if you make any headway with it and I'll post a link.

  10. Hi.
    Got my FTDI 3.3V USB device and started to play with Vue. Still nothing :( Tx and Rx connected together work fine (got what I sent) but Vue doesn't respond. To be continued...
    (sorry for my English - I'm from Ukraine and maybe that's why wxforum doesn't allow me to get registered).

  11. Are you sure you are using 19200 8N1 in your terminal program? That is the default (on a VP2 anyway), where most terminal programs default to 9600 8N1. Is your Tx connected to the console's Rx, and vice versa? Did you remember to connect Ground as well?

    Also, from the Davis Serial Communications Reference Manual:
    "1. Serial commands for Vantage Pro2 must be terminated by a single line feed or a single
    carriage return character, but not both. Older code that terminates commands with bothline feed and a carriage return will not work or will work intermittently. Beware that
    some communciation programs translate a line feed to both a line feed and a carriage

    I don't see why wxforum wouldn't let you register. What does it say? It shouldn't care where you are from. And your English is much better than my Ukrainian. I just know a few words :-)

  12. Interesting - why don't I see "baud rate" at Vue setup options? Maybe it appeares only when Logger connected.
    Have no idea why Vue doesn't answers me. "\n", "TEST" - nothing. Rx to Tx and vice versa - everything's correct. Will try more...

  13. Did you bother to read your manual?

    "Screen 19: Baud Rate (Optional)
    The Baud Rate screen displays only if a weatherLink data logger is installed in the console. The console uses a serial, USB, or Ethernet port to communicate with a computer. If you are connecting the console directly to your computer via USB or Ethernet connection, leave the setting at 19200, the highest rate for the port."

    I don't think I've seen it on mine either. My suspicion is that one of the pins I haven't figured out yet is pulled high or low by the logger to tell the console that it is there. But 19200 is the default. So don't bother trying to change it on the console. Change it in your terminal program.

  14. And just to make sure, you aren't typing


    in the terminal emulator, are you? Because that would be absolutely wrong. This isn't printf.

  15. Yes, and that was the problem - I've found another terminal software and now IT WORKS! (previous didn't send wake up command correctly). So your method works with Vue correct!

  16. Good news! Can you write up a little bit about the setup you used, and I'll post that to wxforum (assuming you still can't access that site). What terminal emulator, what USB->serial converter, and what OS? Any other details you could add would be great.

  17. Sure! BTW, wxforum allows me to enter my personal data and asks me to wait for administrator approval. And I'm sitting and waiting :))))

    Well, USB-COM converter I've bought on e-bay. Like this:

    $15. Good price compared to DataLogger :)

    Windows 7 x64, driver for virtual COM port - no problem.

    I use this terminal program:
    Very customizable, I like it best of all I've seen.

    And now I've flashed new 2.14 firmware and tested WeatherView32 software - everything works SUPERB! YESSS!

    This minutes I'm browsing web looking for different weather software...

  18. Awesome.

    If I remember correctly, you need to tell the wxforum admins when you are signing up why you want to join the board so they can tell the difference between you and a spammer / bot. If you didn't do that, they likely won't let you in.

  19. @DeKay
    > Good news! Can you write up a little bit about
    >the setup you used, I'll post that to wxforum ...

    ... af4ex here from the wxforum, thanks again for your help.

    I have an idea that I would like to bounce around here: in addition to the FTDI adapter, would it make sense to use a pair of XBee transceivers?

    My goal is to set up an RF link between the Davis console, which I keep in the kitchen area for family use, and my ham shack upstairs, where I'd like to disseminate the WX info over APRS.

    So perhaps a pair of XBee 1mw transceivers (300 ft range) from Sparkfun would do the trick.

    I've never used the XBee's, but from what I've read, this would provide transparent serial connectivity from the console to my equipment upstairs.

    I think I'll still need the FTDI adapter, but I can put it upstairs and link it to my ham computer.

    These transceivers are only $22 apiece, so for about $70 or so we can have a wireless serial link from Davis console!

    Would that work? Am I leaving out any critical pieces here?


    BTW, СаД, check your Spam filter. I just signed up to wxforum today. They sent a validation email, but it landed in my Spam folder instead of the Inbox.

  20. Thank you for sharing my progress at WXforum - SPAM folder is empty, I'll try to register with another email address.

    Was trying different software - if software supports Vue (via Weatherlink) it works with our "mod" absolutely correct. Tested Cumulus - perfect.

  21. @John: I noticed after I posted my comment at wxforum that you were a ham. You guys are able to build orbiting space stations with nothing but vaseline and old socks*, so this should be a trivial exercise for you.

    Using the XBees looks like a great idea. I'd never played with them before and always thought they needed a host processor, but after looking at the datasheet, that is clearly not the case. After programming it appropriately, the XBee should interface directly to your console. You will indeed need the FTDI adapter on the PC side. $22 x 2 + $15 is crazy cheap for a wireless Vantage adapter!

    The one thing I'd be concerned about is powering the XBee on the console side: 50 mA is a lot if you are on batteries, with no way to control powerdown. So I'd keep the console plugged in and hook the XBee in to the wallwart DC In input available on the console header. That gives you a nice clean looking install vs. a separate supply.

    Can you post your plan and progress to the wxforum thread? Skipping over the lame Davis dongle opens up a lot of great opportunities for this box that people should be more aware of. I'll also put this idea on the front page of this blog after you get it working (with proper attribution, of course) to bump the visibility of the idea, if you don't mind.

    * Dilbert reference.

  22. @DeKay
    > You guys are able to build orbiting space
    > stations with nothing but vaseline and old socks

    I'm more of a tinkerer/kit-builder, but this is an opportunity to do some creative engineering.

    I've ordered the FTDI adapter from SF. They're temporarily out of stock of the 1mw XBee's (but Digikey carries them for only $19 each).

    I'll be glad to share my progress with you guys, and take advantage of your knowledge in these areas.

    I've also downloaded the SDK stuff from Davis, and will start by reading the reference manual on VP2 serial communications.

    The Davis SDK webpage seems to indicate that they support this kind of 'third party' development, which is why they are making it available for free. I don't begrudge them trying to make a nickel or two from their accessories sales. It supports their development of new hardware, which so far seems first rate.

    73 de af4ex

  23. DeKay,
    While waiting for parts, I'm looking for a 2mm 2x10 PCB connector for interfacing to the WeatherLink port. For prototyping I'll just push pin sockets on the pins, but eventually would like to put the the circuits on a small pcb with a connector, something like this:

    Do you think that would work?

    Tnx, af4ex

  24. John

    Took a quick look. That header looks like it would do nicely.

    BTW, you gotta update your wxforum post with your plans before I spill the beans and take all the credit :-)

  25. > BTW, you gotta update your wxforum post with your plans ....

  26. Looks like this design will be trivial except for that 2x10 position connector. The gradconn part is apparently marketed by a Taiwanese company for OEM consumption. I emailed a request for a sample, but don't really expect they'll send me anything.

    Digikey sells a similar part, ESQT-110-02-G-D-760-ND,
    made by Samtec, but it's out of stock, with resupply expected by end of March.

    How did you hook up your USB-COM?

    Here's a possible solution (that will require some guts to try): the XBee chip just happens to have a 1x10 2mm pitch connector. So it should plug in directly to either row of the WeatherLink connector!

    So if you rewired the console connector internally, it might be possible just to "plug-n-play" with a bare XBee chip! (assuming all it needs is power, gnd and data TX/RX)

    DeKay, you have apparently been inside the console case. How hard would it be to rewire one row of the connector?

    The computer-side connection is even simpler. SparkFun sells a "USB Explorer", which has everthing we need for the uplink: USB connector and socket for the XBee:

    SparkFun just got another batch of the 1mw XBee's with the wire antenna. So I ordered two and also a USB explorer.

    With any luck this will be simpler than I thought. (Though possibly voiding the warranty if the rewiring idea works).



  27. ... Oops, that USB Explorer link should be:

  28. ... hmm, SF even has an XBee dongle that plugs directly into a USB port, no cable required!

  29. John. Here's how I wired up for now. Obviously not a permanent setup!

    I have been inside the unit several times. Believe me, you don't want to rewire the internal connector. It is through hole soldered on a double sided PCB. You'd make a hell of a mess trying to rewire it unless you are VERY skilled in board rework. The relatively fine traces running to this thing don't make it any easier. I'll try to remember to show a picture of the back side of the board in an upcoming blog post

  30. We can order the pcb connector ("2mm elevated pin header") directly from Samtec for $2.75 plus shipping. (Digikey charges over five bucks for it)

    Samtec Part #:ESQT-110-02-G-D-760

    Yes, using this part is _probably_ a better idea than hacking the console PCB apart. :-]

    It might even be the same part that Davis uses for their WeatherLink adapter. I haven't seen one close up.


  31. > ... Samtec for $2.75 plus shipping.

    Shipping is $9.50 (because they ship everything by UPS Red)!

    So, I'll hold off on ordering that for a bit. I'll just wire the pins directly like you did for the initial prototyping.

    (Maybe I can talk SparkFun into making a breakout board and kit for this project.)

  32. Newark has a free shipping deal on now. All web orders of any size - next day shipping. They don't have the Samtec part in stock though. In a pinch, you could order a standard 20 pin 2mm IDC connector and just solder wires to the back of it. All you need are four connections. Newark also has XBees...

  33. > They don't have the Samtec part in stock though.

    The elevated receptable is nice because you can mate it to a printed-circuit board to make a real 'dongle'. Easy to install and remove.

    But that's the mechanical engineering aspect of the project. Let's get the electrical/computer engineering part of it working first.


  34. Picture of the expansion connector now up on the blog.

  35. Just ran into this blog while searching for an inexpensive datalogger for my Wizard III.

    After reading it, and the comments as well, has anyone tried this on a Wizard III? If it works, I certainly hope so, I don't have to get the datalogger that costs almost $200 over here in Europe....

  36. If the Wizard III takes the same datalogger as the VP2 or Vue, then it should work. Give it a try. You're only out ten or fifteen euros if it doesn't. Report back and let me know how you make out.

  37. The Wizard III uses a different one -> 7862. Connector is a rj-11, like the one on a phone.

    No clue what kind of signal it throws out, but can open it up tomorrow and have a good look inside, see where the connector is hooked up to.

  38. Yeah, you're going to have to. Keep me posted. You should be able to identify the processor, look up the datasheet, and then map the pins on the RJ-11 connector to the processor. If you are lucky, it will use the same processor as the console and bring out the same serial connections to the expansion port.

  39. The CPU is a 7372-005C 230, 9813MVA28 (USA Davis Inst Corp). Google does not show any results.
    I can see that it's hooked up to the keypad and the display, but not seeing direct tracks to the weatherlink-port. However these might be below the display on the other side of the circuit board. Meaning I would have to de-solder the display...

  40. Sounds like the board is doube sided so the traces would be on the back. But pinning out the connector isn't going to help you if you don't know what CPU you've got. This is sounding like a custom chip unless you can find any other numbers on it.

    Two pins will have to be power and ground and you could figure out which those were with a multimeter. One will be Tx, and one will be Rx. If you have a multimeter (or a scope, better yet), you could see what voltages each of those float at, guess at which one is Tx and Rx. There is, of course, some potential of blowing something up if you get it wrong though.

  41. Double-sided indeed, tracks on both sides. Display on the back, rest of the components on the front (or the other way around, depending on you're point of view).
    Hmm, well, maybe it's not custom, just relabeled by Davis. The numbers I gave you are all that are on the CPU.

    What is the best way using a multimeter, (standard type, nothing fancy, so no Fluke or anything) to figure out which is which without blowing the thing up? Don't have a scope although I see some used ones for sale on the Dutch equivalent for Ebay.

    Just saw something. Does a Davis 6533 adapter really requires a modem? Looks like one of those + a bit of phonecable with rj-11 connectors is enough to hook it up directly to a pc. Or am I talking nonsense now.

  42. Might work if it is anything like the Envoy. See here, page 4.

  43. Also find this blog while searching for a new datalogger for my Wizard III. I have an original logger but it is defect and I don't want to pay just as Bart said "almost $200 over here in Europe".

    So, if the signal out of the WWIII is the same as mentioned above by the VP2 than it could be fixed in a cheap way.

    I figger out that on the pcb of the datalogger 7862, there are 2 cables soldered (the marks mentioned behind the colours are printed on the pcb):
    -one going to the WWIII-console it has 4-wires: black +P - red GND - green SD - yellow SC
    -the other cable goes to the pc (WeatherLink), it has also 4-wires:
    black GND - red GND - green TxD - yellow RxD

    So this is what I can contribute to this discussion.
    I'm sorry for my bad English, but I'm from the Netherlands

  44. There are 2 circuits on the 7862 datalogger pcb:
    -TC55257DPI-85L - 32,768 WORD x 8 BIT STATIC RAM from Toshiba Semiconductor
    -7372 005C 230 9702MVA02 from USA DAVIS INST CORP

    The first IC is a RAM-chip and the second is a special from Davis, I think. It's almost the same IC as Bart mentioned in his posting above.

    These 2 circuits are on the logger-pcb.

  45. Hi DeKay,

    This is fantastic! Thanks for your efforts, looks like you just helped me afford a better weather station than my crappy unreliable and dying WMR968!

    For logging, I'm using an Alix 3d3 with a native serial port. If I cable up a 3 wire RX/TX/GND serial cable should the TTL from the Vue work like a standard serial port?



  46. Michael. Thanks for your interest.

    "But not just any serial port will do. The lines on the back of the expansion connector are 0 to 3.3V, whereas a normal serial port might be something like -12V to +12V."

    What you are thinking of doing would almost certainly fry your Vue, assuming you plan to connect to J3 of your board. If you want to use that port, you need to find an LVTTL to RS-232 converter. These aren't easy to find. The ones I found in a quick search are 5V (TTL) and not 3.3V (LVTTL) needed by the Vue. So you could either roll your own with something like this:

    Or you could be lucky and get by with this (for $7, you can't go wrong in trying):

    The docs for the Alix hint that you might be able to use J17 or J4 as an LVTTL compatible serial port, but they talk about this as being a build option. You're on your own here.

    Or just use the USB port on the thing and go with a known-to-work solution. Your call.

  47. DeKay,

    Ok, now I see the issue, thanks for your explanation. I don't actually have a Vue yet but thanks for helping me not frying it :)

    Like you say, the USB solution is looking good.



  48. @Remie: Jouw Engels is best te begrijpen hoor ;)

    Don't suppose you can see tracks on the pcb going strait from one connector to the other without an IC in between? If the connectors happen to be hooked up directly, I think it would be easy to hook it up to a computer. Just have to figure out the pin-layout if that's the case.

    I've been a bit distracted, haven't looked at this for a week or so, but in the meantime I managed to get a (used) scope, maybe I can figure out something with that.
    It's a Philips PM3214, an oldie, but maybe it will help.

  49. @Bart: Bedankt, dat m'n school-Engels van heel veel jaren terug nog te volgen is.

    Ok, to the point:
    I've checked-up the tracks on the PCB. It is difficult to see, but the input line's marked SC and SD go directly to the chip marked 7372 005C 230 9702MVA02 from USA DAVIS INST CORP, (further called DAVIS-chip). From the DAVIS-chip there are going tracks to either the
    chip marked TC55257DPI-85L - 32,768 WORD x 8 BIT STATIC RAM from Toshiba Semiconductor (further called the memory chip) and a circuit, I think it is the RS232 converter/stage to the output cable.

    I hope this gives enaough information about the signal flow in the datalogger I have with my Weather Wizard III. (This station is my reference station for my Vantage Pro2 station) You can see this all on Weerstation Hoogeloon (all in Dutch)

    If it make someting clear, I will try to make some pictures from the PCB that I can mail to DeKay, so you can publish.

    It would be great if we could build a PCB that can communicate with the Vantage Pro2/WWIII and has a memory function for a couple of weeks(datalogger). Just as the WeatherLink loggers 6510 and 7862 do.

  50. Kinda lost track of this blog, but just tried something I found but did not get very far.,16211.0.html
    There's a pin-layout in that topic I wanted to try, however, a standard RJ-11 doesn't fit in the Weatherlink port, it's a bit to wide :S
    So no go with the telephone cable. Hopefully I can find that particular connector somewhere with a cable attached to it, I don't have one of those things you can use to put a RJ-11 on a cable.

  51. After looking up pics of the different RJ-connectors with Google, I'm thinking RJ-22, unfortunatly the stores are closed now.

  52. Excellent post!

    I'm working on a project where I'd like to hang an arduino off of my vantage pro allowing me to periodically dump the weather data to an SD card. Basically this would allow me to log all the weather data indefinitely with out needing a laptop around (the arduino is also going to talk to a gps to log the location the weather was observed at).

    So far all is well except for a minor detail ... I can't seem to talk to the console! I had the exact same FTDI adapter laying around from a previous arduino project, modified it to run at 3.3v hooked everything up, fired up minicom. no response. I've tried reversing the tx/rx wires to make sure I hadn't messed that up, and have measured voltage at each pin confirming I'm well grounded.

    At first I was worried that I had either fried something while probing around, or was not using minicom correctly. But heres the mysterious part, at work we have a vantage pro with the weather link, so I borrowed the adapter, snapped it in, fired up minicom and managed to communicate!:


    LOOP 1
    LOO�� ���������������������������������

    Which means, I think I'm correctly configuring minicom, and I think my console is functional. Has anyone else run into anything similar? or perhaps have any suggestions for other tests I can run to debug whats not working here?


  53. kleems: This is very strange. Maybe hook the FTDI adapter back up to your Arduino to make sure it still works?

  54. Thanks DeKay,

    I was also thinking perhaps the FTDI may be shot ... but I can still tx/rx information from my (3.3v) arduino with it, so I assume it still works.

    I've tried two more things since the last comment:

    * adding (3) jumpers from the davis weatherlink to the console instead of plugging the entire adapter in. This allowed me to verify that the three connections your blog indicates are all I need. Sure enough it works fine.
    * directly connecting the arduino to the console and trying to get a response. This did not work.

    I suppose I could buy a weatherlink chop up the USB end of it and via logic level converters hook the weatherlink up to the arduino ... but that sounds like a very expensive hack!

    p.s. it appears we choose very similar projects! I've built a bread proofing box as well! Mine involved an arduino used to dim a light bulb. Would be happy to give details if you're interested.

  55. And I lost track of this blog again...

    Today I tried the pin-layout I found earlier (June 14, 2011 11:01 AM). The Weatherlink connector on the Wizard III is not RJ-11 as I already found out. It's actually a RJ-22, same connector as the one on the wired handset of a phone. Had to get the cable that goes between the handset and the base because those connectors are not sold separately here.

    And... No luck. Tried both the Weatherlink software and HyperTerminal. Depending on the settings (1200 or 2400 baud) and how I soldered the wires (thought I did it the wrong way round) they either freeze in such a way XP's taskmanager can't shut them down or they do nothing. Well, nothing, Weatherlink says it can't find the weatherstation. Loopback test works though, not that it matters I think.

  56. Hmm, no edit option?

    Just remembered that I've got one of these lying around:
    Any chance that one could be used just like the one mentioned in the blog?

  57. In case anyone else is trying to hook an arduino up to their Vantage Pro I thought I'd share the result of a lot of experimentation on my end.

    First my setup:
    - Arduino Pro 3.3v
    - 5v FTDI converted to 3.3v
    - Vantage Pro 2 console

    In previous posts I mentioned that I was unable to communicate with the console using the setup DeKay so graciously exposed. While that is true, I found that if I hooked VCC up to the 3.3v pin on my FTDI everything worked as expected. The voltage off my console (unhooked) reads 2.8v, off my FTDI 3.3v. Perhaps this mismatch was too much for the serial to handle? This was encouraging, so I did the same for my arduion/console setup.

    No luck. Still couldn't get the arduino to talk to the console. After much other debugging I finally decided to hook my FTDI rx to the arduino tx to confirm the arduino was sending the correct info ... turns out it was a garbled mess ("VER" came across as "�Q�C�"). I decided to use the NewSoftwareSerial package to test if it was an issue with my hardware serial ... and voila! communication!

    The arduino and console are sitting right next to me now having a pleasant conversation. Funny how happy a few blinking LEDs can make one feel.

    Next step, send all the data off to an SD card via openLog so my arduino/console can provide a self-sufficient unit that will recorded up to 16GB of weather data with out ever needing a laptop/human around to retrieve the data.

    Thanks all.


  58. @Bart, that should work, assuming that the breakout board is actually populated with a CP2102 :-)

    @Kleems: Good job. Please post a link for any code you might put together for this.

  59. I think I just broke it... The CP2102 (also mentioned on the chip itself ;) ) was recognized for a short time by Windows, then the chip was hot. Too hot. Now it's not recognized anymore.

    Guess I'll have to wait for the original Davis logger cable, ran into someone online who had one lying around catching dust and wanted to get rid of it for a few $. It's been at customs for over a week now.
    After it gets here, I'll try to have a look inside to see what's in there. Hoping that will help others.

  60. Nice work DeKay!

    Working on a project to renew a large old wind direction sign, with glowing lightbulbs.

    The idea: Vantage Vue -> serial 3.3V to 5V -> xbee {wireless} xbee -> arduino -> lightbulbs

    @kleems: do you have some sourcecode, photos?

  61. @everybody: How did you manage the connection from the weatherstation? Cable, connector, box? photos would be nice...

  62. @Dennis. The route you probably want to go is a 20 pin IDC connector with 2mm pitch and some flat ribbon cable with 1mm pitch. Eg



    You can use a small vice or even a cheap clamp from Home Depot to press the cable into the connector. The secret is to apply even pressure across the width of the connector as you go. The Arduino code should be pretty basic for talking to the station.

  63. Great work DeKay, I am currently trying this with a VP1 envoy, all seems good so far......

    I have also designed a small break out board to convert 20 pin 2mm pitch header to FTDI 3.3v converter, cost will be around £5 plus postage if anyone is interested

    You cant find me as belfryboy on wxforum to contact me

  64. When sending the STRMON command, does the raw data continue to stream? I recieive only 2 sets of the raw data and then it quits. Also, could you post an example output string from the LOOP command? I want to make sure mine is responding with the correct information.


  65. Ben

    From this post: "I'm a big fan of STRMON. Just follow it up at some point with STRMOFF or it will print this stuff forever". I have no idea why you would see it only send two sets of data.

    IIRC, LOOP returns binary data, which appears on the terminal as a bunch of unreadable spew.

    Why not download Cumulus for free and test the interface that way?

  66. Thanks for working this out and publishing it!

    I've just hooked up my WRT54G router to the console (it has a 3.3V serial connector easily solderable), and it's happily getting STRMON data.

    Now I need to figure out how to get it to upload it all.

  67. James: No problem. I have the identical router. I'd be interested to see what you come up with.

  68. Well, after a lot of fiddling around trying to build one of the weather daemons for OpenWRT, then trying to install Perl in the 4mb available, I eventually settled for rolling my own solution in Lua. The router now grabs weather data from the console and automatically uploads it to Wunderground.

    I can put the script somewhere if anyone's interested.

  69. James, this sounds awesome. I sent an email to the contact address on your ancient-workshop page. Check it out, please.

  70. I blogged my solution here:

  71. My mind is spinning. I simply want a weather station for Christmas and the ability to "see if it has rained at home". Here in Texas that is becoming a daily question. Started looking for a weather station, I like the Davis Vue, but the software/data logger wow that puts it out of my price range. Google lead me here and to Problem is 99% of what yall are saying is greek to me (56 year old non techie lady). So here is the question, has anyone built a simple cable interface that they will sell? Thanks Ginny

  72. Im with Ginny - love the Vue design but feel the logger kit is so expensive! I would also like to buy a solution that I can afford. (PS do Davis realise that they are losing sales over the logger price especually here in the UK?)

  73. @Ginny: See This post were I provided this link to someone who will sell you the simple cable interface you seek. He is a very reputable member of and many people have had success with his product.

    @Anonymous: See this post on for someone out of the UK who will sell you a logger.

    If Davis had sold the logger cheap, I probably never would have reverse engineered this stuff in the first place. It was certainly with more than a little trepidation that I opened up the console to find out what makes it tick.

  74. Thank You DeKay for all the info and the time you put into this!
    I'm running VP2 without WL for a day now and it works great.
    Next project ill put my hands on is definitely a datalogger interface ;)

    Thanks again!

  75. Hi all, is it a way to build a davis VP2 updater (6312VP2)clone with a MAX232 ?

  76. Could you tell me if I am correct in thinking that any of these cables will work? As far as I understand, the power output isn't a requirement, and I would just require a 3.3v one?

    Thanks for any help, great blog by the way, some great ideas.

  77. apologies, no link attached to previous comment:

  78. Anonymous: Yes, just getting a plain 3.3V one should do the trick.

  79. thank you for that.
    Keep up the good work. Your blog is a great read.

  80. Just a followup, I finally got around to building this using the Sparkfun basic 3.3v breakout and have been able to connect the Vue to my Alix.3 running Meteohub with no problems.

    Biggest issue for me was sourcing the plug for the Vue. 2.0mm plugs are not easy to come by here in Aust, but I managed to find a laptop hard disk connector of the right spacing on ebay that was easy to cut down to the required size.

    Wiring was easy thanks DKay for your efforts.


    1. Excellent. Glad it worked out for you. That connector really is a PITA.

    2. I was able to get connectors as samples from Samtec.
      Goto and click on Sudden Service. I was able to easily get samples of multiple types of 2mm connectors.

      The SQT-110-03-L-D connector is a 2x10 connector that mates fine in the Vantage Pro2 connector. The body is long enough to bring the pins up just above the connector cutout in the Vantage Pro. This allows a PCB or perf board to set down almost flush with the plastic base above the connector. It also has long solder tabs so there is no problem soldering directly to the connector if you wish (I did).

      I also used the SQT-150-01-L-S-RA connector to plug into the RN-XV (Roving networks WiFi module,$39). I chose this because the right angle bend made it easier to solder.

      I repeat. It was easy to get the parts. A couple of days only.

      Jim (KA1ANM on

  81. Hi DeKay,

    Hooked this up the other day and it worked fine but it stopped working after a couple of days, linux no longer recognises the ttyUSB0:

    drivers/usb/serial/usb-serial.c: USB Serial support registered for FTDI USB Serial Device
    usbcore: registered new interface driver ftdi_sio
    drivers/usb/serial/ftdi_sio.c: v1.4.3:USB FTDI Serial Converters Driver
    eth0: no IPv6 routers present
    usb 2-1: new full speed USB device using ohci_hcd and address 2
    usb 2-1: device descriptor read/64, error -62

    Any ideas?

    1. I've read that -62 is a timeout caused by the board not answering to the USB host on your computer. Sounds like a hardware problem with your converter. See this link.

      I don't suppose this helps? This helped me when my computer went to sleep and woke up unhappy with my USB to serial adapter.
      # modprobe -vr ftdi_sio
      # modprobe -v ftdi_sio

    2. Will check that out, I think the module's loaded though.

      I'm wondering if I need to cable Vcc - the computer is an Alix.3d low power, might not be supplying enough voltage or current via USB to the converter...

      Thanks for your help, nothing in your link though...

    3. Not sure how I screwed that link up. Look here:

      The module might be loaded, but I have found with my GoodFET that sleep screws things up and reloading the module fixes it.

  82. DeKay,

    Me again. In your diagram above, you show vcc not connected which means the FTDI is powered from USB, yes? If my low power geode box is not supplying adequate power, could that be my problem?

    I see on wxforum others have connected vcc to + on the FTDI.

    Should the VCC be connected?

    1. The Vcc should not be connected. The FTDI chip is powered from USB. Others might be using Vcc to power an XBee module or something. Think of it this way: this thing is intended to hook up to something RS-232 that won't have any kind of 3.3V Vcc to connect to in the first place.

      And sorry for the slow response. Blogger had marked your post as spam for some reason.

    2. I sent the logs to SparkFun, and they also reckon its a dud. They are sending out a free replacement. That's good service!

      Thanks for the help, I'll update the thread with results.

  83. This should be able to connect it to you local network or a wireless router? WIZ105SR a serial to ethernet with 3.3v

    1. Read this:

      I linked to that from this post:

  84. DeKay . . . Thanks for your postings. I received a Davis Vantage Pro2 for a Christmas present. My first WX Station! I have connected to my PC with a FTDI Basic Breakout USB-Serial. Didn't like the long cables. I then tried bluetooth. Had trouble with the BT Stack (not that I understand it anyway!!). Gave that up!

    I just recently connected thru WiFi using the Roving Networks RN-XV WiFly Module - Wire Antenna purchased at SparkFun. I know very little about WiFi connections -Hosts, Ports, DSN, DCHP, and so forth, but using the 'lets try this (semi)educated guess next' I persevered!

    I now it have my Davis station reliably connected to Virtual Weather Station on my PC using the free HW Virtual Serial Port. I'm happy for now, time to do outside work!

    I post this comment both to thank you (and others) for sharing your quests. Also, if anyone IS interested in my final settings in Routers, Virtual PC Port, and the WiFly RN-XV, I would be glad to share.

    I can be reached at, member KA1ANM.

    Thanks again


  85. I have just found this great blog. Nice information you have here. I have on interesting question: has anyone tried to use the serial output from the weather station to connect to TWO different devices? I'd like to publish data using my web server and also to send data via APRS. I am new to Davis weather stations, but if I am correct, the Davis station needs to get polled for data, it does not output a continuous stream of data... so it's not so easy to actually read data from 2 devices at the same time...

    Fabio IZ4UFQ

  86. You're correct. It is a message / response thing.

  87. Thanks for you answer. Now I have another question: has anyone tried to use that second serial port that seems to be wired to the datalogger connector?

    I mean, are TXD1 and RXD1 somehow useful?

    Fabio IZ4UFQ

    1. I believe someone mentioned that the second serial port is used for wired ISS's.

  88. Well, I own a wired ISS. Time to test that second serial port, once my serial to usb adapters arrive. I am very curious.

    Fabio IZ4UFQ

  89. Is there a video of making this all work, I would like to find a inexpensive way would like to buy multiple Davis VUE's and interface them to either a computer or TNC, and everything requires the weather link, just to get the serial data. so making something that will do this without the storage of the weather link and cost is great but I need to see how you make these. or can you buy them already made by someone.

    1. A video??? Seriously??? No. Do you think you'd get anywhere near the level of detail on a video compared to what is already on this blog???

      If you want one made for you, there is "belfryboy" on Sign up there and send him a PM and he'll look after you.

  90. I don't begrudge them trying to make a nickel or two from their accessories sales. It supports their development of new hardware, which so far seems first rate. domain name

  91. This comment has been removed by the author.

  92. Hi DeKay! I've been reading your blog and I am a big fan of your hacks! Have you tried connecting a Vantage Vue to an Arduino Board? I am currently conducting a research project that would utilize automatic weather stations as early warning systems that would signal the residents of 4 towns to evacuate in case of flashfloods. The serial data would be received by an Arduino Mega2560 and would be transmitted to a remote location via SMS using a GSM module shield.. this raw data would now then be processed and displayed using Cumulus that would upload this data via the internet thru FTP. Several sirens and loudspeakers would also be installed in strategic locations. These warning systems would be triggered again via SMS once a threshold level in rainfall data is reached.

    I would really appreciate your suggestions for this project. thanks!

  93. I try this out, but all the response from the VUE is


    What ever I type in it will only response with that . OK.

    Help Please.

  94. P.S. you can find a screen shot of my terminal here

    1. I know that you got an answer on the wxforum site, but for posterity and others looking at this, it seems that Davis have been cutting these commands out of newer versions of the firmware like you have on your Vue.

    2. I have a new Vantage Pro2. I am trying to communicate to it with my Raspberry Pi, and no matter what command I send it responds "\n\rNO\n\r". Does anybody know what the deal is with Davis silently "upgrading" their products? If there is a discussion about this on wxforum or something that I haven't found yet please redirect me.

    3. Discussions galore.

  95. Hi all, eventually someone has decoded the return commands STRMON
    or nothing ?

    1. All the weather related parameters have been decoded.

  96. Hi Dekay,

    First of all thank you so much for your hard work. This has been a great learning experience trying to replicate your results. Unfortunately, I think I've hit the V3.00 wall with my new Vantage Vue and just wanted to confirm that at this point there is no where else to go.

    It is my understanding that the device on this page is a direct connection from the serial port of the Davis device to the USB port of my computer. In your later posts you assemble an actual data logging device. Do both of these creations no longer work with the firmware update, or just the later?

    Thanks so much for your help and clarification! Keep up the excellent work!

    1. The serial <-> USB no longer works for sure, and presumably a standalone logging device doesn't work either. You are SOL until a workaround is verified.

  97. I've been reading all night and some of this data is 2 years old. I have a Davis 6250 on the way and would like to get data to my PC which is in a closet 30 ft way.
    Is there best place to start? Just when I think I have a good grasp on what direction to go I see an update that things have changed.
    Thanks for all you guys have done!

    1. I saw your post on wxforum where you asked this as well. Well, today is your lucky day. A workaround for the logger issue has been found. Keep an eye on this thread.

  98. Hi,
    Could I strip and wire up the RJ11/12 jack directly to a female Serial DB9 jack? Would the 12v and 3.3v thing matter? Does the serial connection constantly give the weather data or does it have to be asked for? How can I know when there has been a change? How can I decode the serial data received with anything but Perl or C++ (e.g. NodeJS, PHP, Python)?

    I also noticed how you said that the logger communicates with the console via I2C here: Could I use the serial connection on an always running PC and write a script to have it log the data instead of the logger?

    I'm trying to create a website (on my network, not the internet) that would show all of the current weather data for cheap. I have plenty of phone jacks and serial cables that I could cut, strip, and solder together.

    Thanks (I know it's a lot to ask)

    1. I just realized that I could use a voltage divider to drop it to 3.3v. Would it be accurate enough? Should I take the risk or just go with the adapter you specified above?

      Thanks again (this info will help me tremendously)

    2. DaAwesomeP: You need to realize that you are not, in fact, that awesome and so should not be playing fast and loose with any kind of hardware design. For example, RS-232 swings +12V to -12V. A simple voltage divider will fry your console. Get a proper adapter as I have written here and do it right.

      As far as decoding the data goes, I have summarized the protocol here. Roll up your sleeves and get busy.

    3. To use Vantage Pro (Pro 2) serial port, you need to convert them to *12/+12V levels. This is easily done with 3,3V to USB adaptor (search 3,3V TTL 232R on ebay). It cost less than 10 $.

      For software, you can use a free software, named weatherview. I use it with my Vantage Pro for more than 2 years.

      At last, you can also use a Raspberry Pi (with onboard 3,3 V serial) to manage and show on your network your weather data. I made a special image of raspbian OS who work well on Raspberry.

  99. Hmmm... so, I wired up the Sparkfun FTDI adapter to my new VantageVue console as above and all seemed well... except that no matter what I send to the console it just says "OK" back.

    I say "", it says "OK". I say "TEST", it says "OK". Etc... it's nothing if not consistent. Indeed it's nothing BUT consistent.

    Same result using cu from the shell on my Mac, and also using the serial console from the Arduino IDE (line ending is newline only).

    I'd greatly appreciate any suggestions here.

    - Art

  100. Also... tried WeatherSnoop (v3)... it recognizes the serial interface but comms fail thus:

    : Opened socket to localhost:57755 #SerialNetworkAgent
    : Bytes written: <1b> #SerialNetworkAgent
    : Bytes written: <0a> #SerialNetworkAgent
    : Polling... #Davis Agent
    : Bytes read: <0a0d> #SerialNetworkAgent
    : Bytes written: <4c4f4f50 20310a> #SerialNetworkAgent
    : Read operation timed out #SerialNetworkAgent
    : Error 143 accessing port #SerialNetworkAgent

    So that seems to factor out the serial port settings from my end... I'm assuming Weather Snoop does those right. Which seems to leave the physical interface or else a defective VantageVue. The latter seems relatively unlikely. Is it possible Davis has changed something at the interface recently?

    - Art

  101. Ah, so... it appears what I'm seeing is symptomatic of the dreaded V3 / "Green Dot" change. Bah!

    1. Indeed it is. And it sucks that Davis did this just to screw good customers like yourself.

  102. Hi, I have a problem, when connect my Davis vantage VUE, and send any command, or any word, this return to me "OK":

    thanks if can you help me.

    1. Read the posts immediately above yours. You've been screwed by a Davis firmware update.

  103. You can fix Green Dot firmware change. Read this PDF:

    It was made by a brilliant guy who find the answer :)

  104. Has anyone resolved the "green dot" problem on Vantage VUE?
    Does the fix in DavisSPI.pdf work for VUE?
    Because I don't get the "Incompatible logger" error on my VUE, but the only answer I get in minicom is "OK", like others do.

    1. Yes.


  105. looks like the serial protocol documentation moved also to:

  106. Just wanted to chime and say I successfully connected HC-05 3v Bluetooth serial adapter ($5 Ebay) directly to the logger module header. Only takes four wires. Power and RX/TX. Tucked the HC-05 into the batter port. Connected via Windows BT Serial port to the HC-05 and wrote the LOOP and read the data.

    Also Davis Vantage Pro 2 works great by hooking bluetooth power directly to the batter terminals.


  107. Do you think we could send direct data to Internet with these module ESP8266 ESP-12E

  108. Hello.
    can you tell me how to factory reset an existing datalogger?

    1. All you have to do is change the logging interval, I believe. That's the easiest way.

  109. Hi,

    just tried it connecting to my Vue. I use an FTDI borad and minicom, but for every command I send, I just get "OK". Could this be a sign that the unlocking process of the serial port was not successful or might there be and other problem?


    1. Your firmware is V3.0 and above. Davis disabled this function unless you have a Davis datalogger attached. That has since been hacked around as well. See here.

  110. How to see the raw data from outdoor unit

  111. You have pictures of connection to your davis monitor?

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