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Log substitute using the GPS from Moitisier HAT 2
#1
Hi to everybody! Smile

Thanks to all the sponsors who make this nice project feasible. I have supported it buying a Moitissier Hat which it is a great addon to our PI4.

I have been reading all the nice things we can do with our PIs and Moitissier and I saw that it is possible to substitute the Speaed provided by the log (Is it said that way in english?= corredera) NMEA0183 signal with the GPS signal , which with a short code can be converted and forwarded it to OpenCPN and Wind displays so we can get th Speed over ground reading which also serves for getting the real and apparent winds in our cockpit's display and OPENCPN.

My question: is that possible to do it with the Moitissier HAT?  If not, how can we do it?  Can be added as a function by the MASTERS of programming?

I assume that having a GPS inside the system, should be enough to convert it into NMEA0183 speec readings; at least froom the point of viw of someone without any knowledge on hardware and programming.

Thanks!
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#2
If I am not wrong you want to have Speed Through Water directly from Speed Over Ground (GPS) to send to your instruments and have "simulated" True Wind Angle, Speed and Direction. Is this ok?

I think the best way to do this is making a new calculation (STW = SOG) in this Signal K plugin: https://www.npmjs.com/package/signalk-derived-data
Reply
#3
(2020-04-24, 12:57 PM)Sailoog Wrote: If I am not wrong you want to have Speed Through Water directly from Speed Over Ground (GPS) to send to your instruments and have "simulated" True Wind Angle, Speed and Direction. Is this ok?

I think the best way to do this is making a new calculation (STW = SOG) in this Signal K plugin: https://www.npmjs.com/package/signalk-derived-data

Thanks a lot, I will study all these things in a practical manner once I get the hat2.

As I have seen there are many things to do via Signal K.

I will do my best; this OP world is a challenge before starting, but I think all can be done with patirnce, study and help Smile

Thanks!
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#4
Yes, OP is really flexible because there are always more than one way to do something and that could be a little bit stressing at the beginning but do not be afraid to experiment and you will enjoy it.
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#5
(2020-04-29, 11:26 AM)Sailoog Wrote: Yes, OP is really flexible because there are always more than one way to do something and that could be a little bit stressing at the beginning but do not be afraid to experiment and you will enjoy it.

True Sailoog,

today i tried an different access for my GPS Stick (ublox7) as i got errors.

After using gpsd the quirks were gone. Look at the End of this Thread.
http://forum.openmarine.net/showthread.php?tid=1013

Regards, Holger
Reply
#6
(2020-04-24, 12:57 PM)Sailoog Wrote: If I am not wrong you want to have Speed Through Water directly from Speed Over Ground (GPS) to send to your instruments and have "simulated" True Wind Angle, Speed and Direction. Is this ok?

I think the best way to do this is making a new calculation (STW = SOG) in this Signal K plugin: https://www.npmjs.com/package/signalk-derived-data

Hi Sailloog, could you explain and write the code to do the STW = SOG calculation? And what should I change in the plugin?

Thanks
Comet 1000 - Openplotter under construction
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#7
(2020-11-10, 09:42 PM)niklun Wrote:
(2020-04-24, 12:57 PM)Sailoog Wrote: If I am not wrong you want to have Speed Through Water directly from Speed Over Ground (GPS) to send to your instruments and have "simulated" True Wind Angle, Speed and Direction. Is this ok?

I think the best way to do this is making a new calculation (STW = SOG) in this Signal K plugin: https://www.npmjs.com/package/signalk-derived-data

Hi Sailloog, could you explain and write the code to do the STW = SOG calculation? And what should I change in the plugin?

Thanks

Sorry, never tested that but if I am not wrong it should be possible to calculate SOG just using the plugin settings
Reply
#8
Niklun, this might be what you  are looking for, the derived data plugin calculates ground wind speed & direction based on sog & cog and sends it as environment.wind.angleTrueGround and environment.wind.speedOverGround. Then I have some node red which takes the values of thos and sends them as environment.wind.speedTrue and environment.wind.angleTrueWater.

Code:
[
   {
       "id": "566b4bb6.eac0a4",
       "type": "signalk-subscribe",
       "z": "750594de.8e494c",
       "name": "environment.wind.speedOverGround",
       "mode": "sendAll",
       "flatten": true,
       "context": "vessels.self",
       "path": "environment.wind.speedOverGround",
       "source": "",
       "period": 1000,
       "x": 240,
       "y": 1040,
       "wires": [
           [
               "f784a4c3.41c338"
           ]
       ]
   },
   {
       "id": "8334969e.d3b278",
       "type": "signalk-send-pathvalue",
       "z": "750594de.8e494c",
       "name": "",
       "source": "",
       "x": 990,
       "y": 1020,
       "wires": []
   },
   {
       "id": "f784a4c3.41c338",
       "type": "function",
       "z": "750594de.8e494c",
       "name": "environment.wind.speedTrue",
       "func": "msg.topic = \"environment.wind.speedTrue\";\nreturn msg;",
       "outputs": 1,
       "noerr": 0,
       "x": 620,
       "y": 1060,
       "wires": [
           [
               "8334969e.d3b278"
           ]
       ]
   },
   {
       "id": "76df8946.05b5e8",
       "type": "signalk-subscribe",
       "z": "750594de.8e494c",
       "name": "environment.wind.angleTrueGround",
       "mode": "sendAll",
       "flatten": true,
       "context": "vessels.self",
       "path": "environment.wind.angleTrueGround",
       "source": "",
       "period": 1000,
       "x": 240,
       "y": 1100,
       "wires": [
           [
               "c10abcac.64d97"
           ]
       ]
   },
   {
       "id": "c10abcac.64d97",
       "type": "function",
       "z": "750594de.8e494c",
       "name": "environment.wind.angleTrueWater",
       "func": "msg.topic = \"environment.wind.angleTrueWater\";\nreturn msg;",
       "outputs": 1,
       "noerr": 0,
       "x": 640,
       "y": 1100,
       "wires": [
           [
               "cd2581b1.513c6"
           ]
       ]
   },
   {
       "id": "cd2581b1.513c6",
       "type": "signalk-send-pathvalue",
       "z": "750594de.8e494c",
       "name": "",
       "source": "",
       "x": 990,
       "y": 1080,
       "wires": []
   }
]

Then set signalk to nmea plugin to create VWT sentence and opencpn recognizes that.
Reply
#9
(2020-11-11, 07:38 PM)PaddyB Wrote: Niklun, this might be what you  are looking for, the derived data plugin calculates ground wind speed & direction based on sog & cog and sends it as environment.wind.angleTrueGround and environment.wind.speedOverGround. Then I have some node red which takes the values of thos and sends them as environment.wind.speedTrue and environment.wind.angleTrueWater.

Code:
[
   {
       "id": "566b4bb6.eac0a4",
       "type": "signalk-subscribe",
       "z": "750594de.8e494c",
       "name": "environment.wind.speedOverGround",
       "mode": "sendAll",
       "flatten": true,
       "context": "vessels.self",
       "path": "environment.wind.speedOverGround",
       "source": "",
       "period": 1000,
       "x": 240,
       "y": 1040,
       "wires": [
           [
               "f784a4c3.41c338"
           ]
       ]
   },
   {
       "id": "8334969e.d3b278",
       "type": "signalk-send-pathvalue",
       "z": "750594de.8e494c",
       "name": "",
       "source": "",
       "x": 990,
       "y": 1020,
       "wires": []
   },
   {
       "id": "f784a4c3.41c338",
       "type": "function",
       "z": "750594de.8e494c",
       "name": "environment.wind.speedTrue",
       "func": "msg.topic = \"environment.wind.speedTrue\";\nreturn msg;",
       "outputs": 1,
       "noerr": 0,
       "x": 620,
       "y": 1060,
       "wires": [
           [
               "8334969e.d3b278"
           ]
       ]
   },
   {
       "id": "76df8946.05b5e8",
       "type": "signalk-subscribe",
       "z": "750594de.8e494c",
       "name": "environment.wind.angleTrueGround",
       "mode": "sendAll",
       "flatten": true,
       "context": "vessels.self",
       "path": "environment.wind.angleTrueGround",
       "source": "",
       "period": 1000,
       "x": 240,
       "y": 1100,
       "wires": [
           [
               "c10abcac.64d97"
           ]
       ]
   },
   {
       "id": "c10abcac.64d97",
       "type": "function",
       "z": "750594de.8e494c",
       "name": "environment.wind.angleTrueWater",
       "func": "msg.topic = \"environment.wind.angleTrueWater\";\nreturn msg;",
       "outputs": 1,
       "noerr": 0,
       "x": 640,
       "y": 1100,
       "wires": [
           [
               "cd2581b1.513c6"
           ]
       ]
   },
   {
       "id": "cd2581b1.513c6",
       "type": "signalk-send-pathvalue",
       "z": "750594de.8e494c",
       "name": "",
       "source": "",
       "x": 990,
       "y": 1080,
       "wires": []
   }
]

Then set signalk to nmea plugin to create VWT sentence and opencpn recognizes that.


Code:
Thanks to all of you for the great help! Saillog, I didnt see your last reply bak in April. MY OP still unmounted as I don't have electrical system yet
Reply
#10
(2020-11-11, 07:38 PM)PaddyB Wrote: Niklun, this might be what you  are looking for..
Also, to see the wind data in opencpn dashboard you could try making a signalk port 3000 connection in opencpn.
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