Topic: Davis Wireless to IP

[ziplockk]

AS PCB costs are now so low I've put together a board that allows Davis wireless comms (VP2/Vue) to be surfaced on your home network as JSON encoded data on a UDP broadcast, connectivity using WIFI. Perfect for integrating with almost anything you like (node red, other weather station software). PCB will have programming headers for all the devices onboard, all the software is FOC and arduino based. PCB's are designed for practical home assembly (but not for beginners). I've run the prototype to this prototype for the last year with zero issues (completely reliable 24/7/365) and using only milliwatts of power.

Last prototype up and running an hour after getting the boards : https://www.dropbox.com/s/833sop3xg35q68l/2019-11-20%2001.35.14.mp4?dl=0 happily rxing VP2 traffic from my station (and showing very good rssi thanks to board design around the radio modules . . . noticbly better than my lashed up prototype.

Final re-spin of the board to make it smaller and finalise design to easily available components will be done shortly

Intent is to make this completely open, software and hardware.

I use the same board for procesing data from another RF network I run using the same concept.

All my processing is done in a virtual machine these days so network integration is the only way to go.

I run these network bridges in a box in the attic where they get great RF RSSI

If of interest I'll publish more.

May be interested in someone testing with a Vue too . . .

One for the makers . . .

[vreihen]

Just to clarify, this board receives Davis VP2 ISS broadcasts and re-broadcasts them on the local wifi via JSON USP?

As the developer of the WeeWX WeatherFlow and Atmocom UDP drivers, my ears just perked up!  How do I get my hands (and soldering iron I assume) on one of these boards?????

[galfert]

When you say home assembly are you talking about soldering? Because it looks like it requires SMD soldering skills. No through hole design 

[ziplockk]

Soldering appropriate sized smd by hand is far faster than soldering through hole, even when you are old and blind like me . . . . . . the microcontroller in the middle may be an exception (I have no problem with it but I'm used to hand soldering smd) but that can easily be made a DIL part . . . in fact the whole board could be, it's just an hours time re laying out the board.

The board you see is hand soldered with a normal fine tipped soldering iron.

As I said . . . for the makers . . . sufficient interest could justify having full boards fabricated or a through hole only board made . . . PCB board manufacture is getting pretty cheap these days.

Davis/RF -> JSON/UDP/IP/WIFI . . . is what it does (amongst other things) . . . for each RF transmission received . . .

[mcrossley]

A few questions...

Is it using your wind correction interpolation routines, or just relaying raw wind data?

Does it work with the different regions bands and channels?

One thing that would be missing from making this a potential console replacement would be barometric pressure.

[ziplockk]

Obviously this is not intended as a replacement for anything Davis do . . . this is very much DIY and Amateur, hence the 'open' nature, just advancing the possible and giving a little capability back to the community. Those who want a Davis console will not get one with this kit and will have to buy one . . . Those who don't want a Davis console probably already have an alternative as those alternatives are already freely available. This just puts the required hardware on one PCB which is not a locked down design. For example Meteohub/Meteostick (?)  (I own one and it was my first venture into this area) is a commercial solution, well supported and a great product (I still run one, but my primary solution is basically this solution)

I happen to source baromatric pressure from other nodes in my sensor network, however adding the ability to put a barometric sensor on the board is not difficult at all, the parts, however, are absolutely not hand solderable . . . but there are workarounds for that problem for the determined maker (buy the part on a carrier board with hand solderable pins - easily available :
https://coolcomponents.co.uk/products/mpl3115a2-altitude-pressure-sensor-breakout?variant=45222897230&currency=GBP&gclid=Cj0KCQiA5dPuBRCrARIsAJL7oeiOOYwPcRzlmE87tC1Nk3DzSh5VHC3LJeWv8LQcoajJ2rOimxLwdZEaAlt6EALw_wcB

The wind speed correction algorithm can be applied however this isn't in the current software as I process it centrally (and store corrected and uncorrected data) . . . but again, that doesn't present a technical problem.

The radio hardware is compatible with all the required frequencies, but requires a specific module to be fitted depending on the frequency range, all the required frequency modules are freely available on the open market around the world.

The software to drive the radio and decode Davis traffic is freely available and in the open and requires almost no adaption for use in this environment. it supports all sorts of configurations and has done for many years.

The software to bridge that data to the WIFI network is trivial.

As I say I use precisely the same hardware to bridge between a larger scale RF connected sensor network and an IP network which is nothing to do with Davis kit whatsoever, it just so happens, by only slight coincidence, that the same radio hardware can receive the Davis comms traffic by running an appropriate configuration.

[ziplockk]

https://www.dropbox.com/s/bugyr44lo2ogdk0/2019-11-25%2019.31.01.jpg?dl=0

Prototype has served its purpose, and both will now be put in a box in the attic, powered and will feed my vp2 and other sensor network data onto my network (don't want to waste those components ), probably never to be seen again . One small design bug in the hardware, trivial to resolve. I will be putting a DC power barrel connector on the final board revision rather than a USB socket.

I've looked at pressure sensors, the one I use (for this kind of thing) is the Bosch BMP280, regardless as I thought none are available in hand solderable technologies, which means at least part of the board has to be smd, everything else (as it happens) is available in smd OR through hole.

It's been a while since I even looked at through hole parts . . . in low volumes they seem to cost about 20x the cost of smd parts (wow !) . . . which is disappointing . . . I've gotten used to the cost of SMD passive parts being so low that they are almost irrelevant . . .

One of the micros runs the ISSrx arduino application from kobuki (straight out of the github repo, or whatever you like - it's open to reprogramming using the arduino IDE), the other runs the WIFI integration, JSON/UDP encoding, windspeed correction (both raw and corrected will be encoded), Signal RSSI, battery status etc will all be encoded also, I may also put a proper vector based wind direction averager onboard (I do that in my database at present, but they are simple enough to do). That application I have written and will put online, it can also be changed using the Arduino IDE. There will also be an Atmel AVR 6 pin ISP Header to allow reflashing of the Atmel part with a new bootloader. Just because

Power supply will be 5V, 250mA max, 2.1mm barrel I think. mounting holes in the board will be 3mm, antenna via SMA connector.

Both these boards have run for 24 hours with zero packet drops . . . which is pretty good . . .

[vreihen]

There are plenty of options for BMP280 breakout modules in the Arduino and Pi arena.  I bought a package of five for peanuts from Amazon, because they were in stock for free Prime shipping for less than one module from Adafruit.....

[ziplockk]

Indeed, and that is always an option . . . only issue is that given the number of bmp280 modules around which have different pinouts, designing a board that matches the pinouts is a challenge, 4 pins in all possible layout combinations gives far too many pin layouts . . . hence using a specific module which you can guarantee the pinout of . . .
 no point in fabricating boards then being unable to source a compatible component . . .

[ziplockk]

Rev B in fab in Hong Kong as I type.

Smaller board, debugged design, will take the most common pressure sensor I can find on ebay . . . difficult parts are through hole.

https://www.dropbox.com/s/7d9a0brgyvcw5ad/bridge_b.png?dl=0

Be here in a week or so, built up and ready for someone to test . . .

[virtex]

Hello,

it looks like that you are designing in KiCAD (at least the 3D Viewer and the components naming looks similar). Are you willing to share the schematic and the PCB design?

I also see some improvements in PCB Design, for example blocking caps on ICs, more/other ground planes, heat dispatching on LDO, why is there an ĩC additional to the ESP8266.

I really appreciate such kind of open source approaches.
I would like to contribute the improvements I see.

I hope it is understandable, I'm not a native speaker.

[ziplockk]

Hi, yes I can share.

I have subsequently added decoupling caps on the ESP, AVR and Radio power supplys and a full ground plane on both sides of the board.

The LDO does not produce any significant heat.

The AVR/RFM69 radio is a well proven solution to recieving Davis RF traffic. At the time I designed this (some time ago) the RFM69 solution was not reliable with the ESP8266, that may have changed but I would want to prove it's robust before using it.

I have a second use for the board which is better met using the AVR and ESP combination also

I'll upload things to github at some point when time allows.

[ziplockk]

https://github.com/fergusd/RFM69WIFIBridge

Latest design files, haven't been fabricated yet but evolved from original design.

I've been having a problem getting the esp12-e into programming mode, suspect the cheap ebay modules I bought are not all they seem, however known good modules work just fine. I'd hold on using this unless you can solve that problem yourself, or I get time to solve. I have some samples on order to investigate.

Suspect some sellers are selling esp12-f's as -e's . . .

Anyway, feel free to optimise.

Ultimately getting the SMD parts put on the board when it's fabricated is very low cost.

Of note this board also has a pin header to connect a pressure sensor . . .

Ciao from the very snowy Italian/Austrian tirol

Software wise, I'll upload that in the new year, too much powder needing tracked here !

[safuser]

Downloaded SCH files from github link.  Am unable to open them in Eagle?  What program did you use to create?

Thanks!

[ziplockk]

I use https://kicad-pcb.org/

I used to use Eagle, but Kicad has now matured enough such that I will never use Eagle again . . . never mind pay for it

Fd