Log wind data on the fly

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houlihan

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Our wind sensor is a TackTick as part of the TackTick (Raymarine) wireless network. I want to log NMEA wind sentences (AWD, AWS, TWD, TWS (if there even are NMEA sentences for each of these; TWS and TWD may be post hoc calculations). I have an open NMEA-out in the TackTick Wireless interface. The othere one is used for an NMEA wireless gateway to connect to an iPad. I would want to filter out of the NMEA data stream all the sentences I don't need but retain the NMEA wind data with a contemporaneous time stamp. My aim is to align wind data with the corresponding time of a track point on a Yellowbrick log after a distane race. The further aim is go back later and review the track and answer the question: at the particular moment we did a course change, what was the wind doing at that same moment (which may have prompted the course change)? I would like to save these data to a spreadsheet file and also use the data to draw a graph vs time. I know I can display the data in iNavX but there is no way to save it.

Thanks
 
I am sad to admit that I do exactly this........however I use the NMEA output from a Raymarine C80 and log it on a Windows PC running Navmonpc, which is dated but works well and is robust, [provides realtime time histories of wind speed and direction, which adds a dimension to the instruments. Its a bit clunky and the PC uses a bit of battery power. I would like to move on but have little time to dabble with Arduinos and the like at the moment. Prepare for a barrage of advise from the better informed:-)
 
I should have clarified that my computer is MacOS, and not Windows. I basically want to collect the wind data in real time on the boat during a distance race and then archive it for later review. Then align the time stamp of a particular bit of data with that of position at that same moment on the Yellowbrick track.
 
houlihan said:
I should have clarified that my computer is MacOS, and not Windows. I basically want to collect the wind data in real time on the boat during a distance race and then archive it for later review. Then align the time stamp of a particular bit of data with that of position at that same moment on the Yellowbrick track.
Click to expand...

Open CPN runs on OSX, and logs all the data it sees on the NMEA bus.
I haven't played with this feature extensively, but it's worth a look
 
Download and compile kplex. Use the develop branch on github: its stable and has a bunch of bug fixes but master should still work for this task:
GitHub - stripydog/kplex at develop
You may need to install xcode if you don't have it already (which is free and from apple) but kplex doesn't require any dubious installation as root or depend on a raft of python modules.
Hook up your nmea output to a usb-to-serial adapter. Chose one with an ftdi chipset for minimal hassle on os x
run kplex in a terminal window and check you're getting the data you want:
./kplex -f- serial:filename=/dev/cu.usbserial1,ifilter='+**AWD:+**AWS:+**TWD:+**TWS:-all',direction=in file:direction=out,timestamp=s
This should get you the data you want with the timestamp attached as an NMEA TAG (ie the "proper" way to timestamp NMEA data). The timestamp is in "unix time" (seconds since jan 1st 1970 UTC). You can get the timestamp in milliseconds using "timestamp=ms" instead of "timestamp=s"
If the data looks right you can kill kplex (send it ctrl-c from the terminal) and restart, outputting data to a file:
./kplex -f- serial:filename=/dev/cu.usbserial1,ifilter='+**AWD:+**AWS:+**TWD:+**TWS:-all',direction=in file:direction=out,timestamp=s,filename=/tmp/my_log_file,append=yes

Above is not guaranteed free from typos. I can plug my mac in to the boat this evening to check specifics. More detail available if you're not comfortable with github etc.
 
Last edited:
laika said:
./kplex -f- serial:filename=/dev/cu.usbserial1,ifilter='+**AWD:+**AWS:+**TWD:+**TWS:-all',direction=in file:direction=out,timestamp=s,filename=/tmp/my_log_file,append=yes
Click to expand...

..if you're going to run this stuff regularly you stick all the config in a config file and just run "kplex" (ie no, you don't have to type all that gubbins every time you run it)
 
If you're pulling in NMEA from the windicator anyway, I'd suggest also logging the GPS output for position, rather than relying on YB or whatever. The latter can have issues, and certainly won't update as often as your own GPS. Also, the SOG will allow for quick and dirty polar creation/comparisons (SOG != speed through the water etc etc).
 
An interesting though. I've been recording wind speed and direction hourly in the paper log, but having it with the GPS track would be useful. I have Garmin kit onboard and it does record speed in a graph so the data must be in there somewhere.
 
Couple of suggestions.

Yacht devices make a nmea 2000 VDR device that records all the network data. You can then export that to excel and do what you want with it.

Alternatively you could use a low cost computer like a raspberry pi, bring your data into that via signal K and export it to an Influx database.

That can then be exported into grafana and you can then graph all the data in time series.

As others say, you can use open cpn to create polars, and do lots of this functionality.

Take a look at openplotter which ecorperates a lot of this and isn't too difficult to get up and running.
 
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