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Generate custom NMEA0183 sentence in v0.8
#1
Hi all,

Just started seriously playing with OpenPlotter as I have decided to build myself some dedicated hardware. I am running a RPi 3 with OpenPlotter 0.8 with so far a GPS shield a BMP180, HTU210 and an IMU9 9-DOF. All working as advertised. 

I have some temperature probes to add and will soon be adding an RTC module

I have a 800x600 touchscreen but the touch doesn't work - I suspect the USB interface but I'm not worried about that as I don't like touch screens at sea anyway so will use operate it with a waterproof keyboard and trackball. 

Currently in the process of designing and building a high efficiency DC - DC converter to power the PI from 12V  and housing it all in what will be reasonably water resistant housing. 

Now to my question. I want to feed temperature and pressure into OCPN. v0.8 of OP generates the $OSXDR NMEA0183 sentence but OCPN does not handle that so I'd like to generate different sentences appropriate to OCPN (MTA for temperature for example). How do you change the sentences generated by OP is there a hidden interface somewhere? 

I see the in the current manual for 0.9 there does seem to be some form of interface for cusomising sentences but I don't want to play with v0.9 yet because I don't currently have the download capacity or want to play with an alpha version while I am still building and testing hardware. 

I have looked at the OCPN plugin "NMEA Converter" or some similar name but it can't handle multiple instances of the same sentence carrying differing information fields so can't process OSXDR in this case. However if I can change the name of the sentence I can probably process it the NMEA converter plugin. 

Thanks in advance Smile
Reply
#2
(2017-01-23, 08:33 AM)Littlechay Wrote: Hi all,

Now to my question. I want to feed temperature and pressure into OCPN. v0.8 of OP generates the $OSXDR NMEA0183 sentence but OCPN does not handle that so I'd like to generate different sentences appropriate to OCPN (MTA for temperature for example). How do you change the sentences generated by OP is there a hidden interface somewhere? 

Thanks in advance Smile
Hello

Look at 1w.py in the the OP directory (normally ~/.config/openplotter or something like this)

I changed the sentence which is generated in this file, as my cockpit instrument will only read and show MTW sentence. But I want it to show the value from the DS18B20 sensor ... so I changed the values in 1w.py from XDR to MTW.

Fair winds
Christian
Reply
#3
(2017-02-14, 06:20 PM)CVL Wrote:
(2017-01-23, 08:33 AM)Littlechay Wrote: Hi all,

Now to my question. I want to feed temperature and pressure into OCPN. v0.8 of OP generates the $OSXDR NMEA0183 sentence but OCPN does not handle that so I'd like to generate different sentences appropriate to OCPN (MTA for temperature for example). How do you change the sentences generated by OP is there a hidden interface somewhere? 

Thanks in advance Smile
Hello

Look at 1w.py in the the OP directory (normally ~/.config/openplotter or something like this)

I changed the sentence which is generated in this file, as my cockpit instrument will only read and show MTW sentence. But I want it to show the value from the DS18B20 sensor ... so I changed the values in 1w.py from XDR to MTW.

Fair winds
Christian

Thanks Christian. I had already found that but not been back here to update.. I haven't got the pressure to display in OCPN but haven't spent a lot of time on finding out what sentence it uses. Temperature was easy. I've been busy making a script to generate a polar file from logged NMEA data.
Reply
#4
(2017-02-14, 11:02 PM)Littlechay Wrote:
(2017-02-14, 06:20 PM)CVL Wrote:
(2017-01-23, 08:33 AM)Littlechay Wrote: Hi all,

Now to my question. I want to feed temperature and pressure into OCPN. v0.8 of OP generates the $OSXDR NMEA0183 sentence but OCPN does not handle that so I'd like to generate different sentences appropriate to OCPN (MTA for temperature for example). How do you change the sentences generated by OP is there a hidden interface somewhere? 

Thanks in advance Smile
Hello

Look at 1w.py in the the OP directory (normally ~/.config/openplotter or something like this)

I changed the sentence which is generated in this file, as my cockpit instrument will only read and show MTW sentence. But I want it to show the value from the DS18B20 sensor ... so I changed the values in 1w.py from XDR to MTW.

Fair winds
Christian

Thanks Christian. I had already found that but not been back here to update.. I haven't got the pressure to display in OCPN but haven't spent a lot of time on finding out what sentence it uses. Temperature was easy. I've been busy making a script to generate a polar file from logged NMEA data.
Hi Chris,
no problem. If you get your script running I would be interested...
Reply


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