Open CPN Android - Bluetooth to RS232 for exporting NMEA to Tiller Pilot

[Greg M]

Back in 2017, 'silentwings39' started a very interesting thread called 'Android Tablet - NMEA - BLUETOOTH'. I concur with everything s/he said in praise of the developers of this wondrous navigation system.
I am trying to do something that was flagged in that thread. But I am not needing to import AIS, I am trying to use a Bluetooth to RS232 serial adaptor to send tracking data to a Raymarine ST1000 tiller pilot. I have it working well using an old Toshiba Notebook with a USB to RS232 dongle, but as my boat is a little Catalina 25 and as I sail single-handed, I would like to dispense with all the paraphernalia, including the notebook with the above dongle, the external GPS puck and 12/19 volt power adaptor etc. So I have installed Open CPN on a powerful Lenovo tablet and V5.8.4 works splendidly with the inbuilt GPS and my charts.

In order to try to have the tablet navigate the boat, I have purchased a bluetooth to RS232 adaptor that has at its core the Bolutek BC04-B module. The adaptor receives and sends serial data through its DB9 connector (tested) and the Built-In Bluetooth 'Connection' within Open CPN Android scans and finds the adaptor and the debug window shows it is sending data. But it does so for only 4 or five seconds before Open CPN crashes, so I have been unable to test it with the tiller pilot.

I know there are other solutions, like sending the data over wi-fi or by way of the tablet's USB port, or pairing the tablet with the notebook, but I am hoping to avoid having the tablet tied to a USB cable and trying to keep it as simple as possible.

Is there a possible solution to my dilemma?

Thanks again to the wonderful developers and the huge family of Open CPN devotees.

Greg

[Greg M]

An update on my previous post.

I think I have cracked it. I was trying to get Open CPN to talk to the Bluetooth/RS232 adaptor by way of the Bluetooth connection within Open CPN 'Connections'. On a whim I decided to try to connect to the adaptor by way of the 'Serial' connection, even though Android doesn't provide for Com ports.
Voilà! it worked. Open CPN immediately found it and, as I had already changed the adaptor's baud rate to 4800, it automatically filled in all the fields for communication and the debug window didn't miss a beat.

I will try it with the Tiller Pilot when I am next on the boat and post the results here (in case anyone in the future finds this to be a useful workaround).

Regards to all.

Greg

[CapsizedVeteran]

Great work! Please do report back and let us know if it works out as intended!

[Greg M]

Originally Posted by CapsizedVeteran

Great work! Please do report back and let us know if it works out as intended!

Will do, either way.

[rgleason]

Originally Posted by Greg M

An update on my previous post.

I think I have cracked it. I was trying to get Open CPN to talk to the Bluetooth/RS232 adaptor by way of the Bluetooth connection within Open CPN 'Connections'. On a whim I decided to try to connect to the adaptor by way of the 'Serial' connection, even though Android doesn't provide for Com ports. Voilà! it worked. Open CPN immediately found it and, as I had already changed the adaptor's baud rate to 4800, it automatically filled in all the fields for communication and the debug window didn't miss a beat.

I will try it with the Tiller Pilot when I am next on the boat and post the results here (in case anyone in the future finds this to be a useful workaround).
Greg

Greg we are interested in your discovery and success.



Would you mind writing this up in detail for other users? We will find a place for it in the documentation.

[Greg M]

Originally Posted by rgleason

Greg we are interested in your discovery and success.
Would you mind writing this up in detail for other users? We will find a place for it in the documentation.

Thanks for your interest Rick
I will be onboard and able to test this late next week. If it works, I will post full details on the process. If it doesn't work, I will try to identify the reason/s why,.

Regards,

Greg

[Greg M]

Update: At this stage, I can report mixed results. Whilst the NMEA data stream from the Bluetooth/RS232 adaptor appears to be okay, apart from a strange "$ G N A C C U R A C Y" entry (see below) and as I was able to get ST1000 to go into tracking mode properly ONCE, all subsequent attempts failed. When switching to tracking mode on the ST1000 it does not seem to be able to find the distance in nautical miles to the waypoint and so tracking mode can not be confirmed. In any case, I will continue trying to find the problem and report back if I have any success.

Greg

G R E E N > ( ) $ G N A C C U R A C Y , 2 . 0 , 2 4 . 0 , 1 . 0 , 1 6 . 8 * 1 E < 0 x 0 D > < 0 x 0 A >
< B L U E > - - > ( 9 8 : D 3 : 3 1 : F 7 : 5 3 : 2 E ) $ G N A C C U R A C Y , 2 . 0 , 2 4 . 0 , 1 . 0 , 1 6 . 8 * 1 E < 0 x 0 D > < 0 x 0 A >
< G R E E N > ( ) $ P M T K A G C , 0 1 0 6 0 7 . 0 0 0 , 5 3 7 4 , 5 2 9 5 , 5 9 9 7 , 5 9 4 1 , 0 , 0 , 0 , 6 , 1 2 8 , 0 * 7 D < 0 x 0 D > < 0 x 0 A >
< B L U E > - - > ( 9 8 : D 3 : 3 1 : F 7 : 5 3 : 2 E ) $ P M T K A G C , 0 1 0 6 0 7 . 0 0 0 , 5 3 7 4 , 5 2 9 5 , 5 9 9 7 , 5 9 4 1 , 0 , 0 , 0 , 6 , 1 2 8 , 0 * 7 D < 0 x 0 D > < 0 x 0 A >
< G R E E N > ( ) $ P M T K A G C , 0 1 0 6 0 7 . 0 0 0 , 5 3 7 4 , 5 2 9 5 , 5 9 9 7 , 5 9 4 1 , 0 , 0 , 0 , 6 , 1 2 8 , 0 * 7 D < 0 x 0 D > < 0 x 0 A >
< B L U E > - - > ( 9 8 : D 3 : 3 1 : F 7 : 5 3 : 2 E ) $ P M T K A G C , 0 1 0 6 0 7 . 0 0 0 , 5 3 7 4 , 5 2 9 5 , 5 9 9 7 , 5 9 4 1 , 0 , 0 , 0 , 6 , 1 2 8 , 0 * 7 D < 0 x 0 D > < 0 x 0 A >
< G R E E N > ( ) $ P M T K T S X 1 , 1 1 5 8 2 4 , - 5 3 3 2 1 . 3 1 4 , 4 5 . 4 6 8 , 4 4 . 0 9 1 , 4 d 5 c 0 0 0 0 , - 5 . 3 2 4 6 7 8 , - 5 . 3 3 2 1 3 1 , - 0 . 4 5 2 8 6 3 , - 0 . 1 9 9 3 3 7 , 1 . 4 9 5 6 9 7 , - 5 . 3 3 2 , 1 . 0 * 5 0 < 0 x 0 D > < 0 x 0 A >
< B L U E > - - > ( 9 8 : D 3 : 3 1 : F 7 : 5 3 : 2 E ) $ P M T K T S X 1 , 1 1 5 8 2 4 , - 5 3 3 2 1 . 3 1 4 , 4 5 . 4 6 8 , 4 4 . 0 9 1 , 4 d 5 c 0 0 0 0 , - 5 . 3 2 4 6 7 8 , - 5 . 3 3 2 1 3 1 , - 0 . 4 5 2 8 6 3 , - 0 . 1 9 9 3 3 7 , 1 . 4 9 5 6 9 7 , - 5 . 3 3 2 , 1 . 0 * 5 0 < 0 x 0 D > < 0 x 0 A >
< G R E E N > ( ) $ P M T K T S X 1 , 1 1 5 8 2 4 , - 5 3 3 2 1 . 3 1 4 , 4 5 . 4 6 8 , 4 4 . 0 9 1 , 4 d 5 c 0 0 0 0 , - 5 . 3 2 4 6 7 8 , - 5 . 3 3 2 1 3 1 , - 0 . 4 5 2 8 6 3 , - 0 . 1 9 9 3 3 7 , 1 . 4 9 5 6 9 7 , - 5 . 3 3 2 , 1 . 0 * 5 0 < 0 x 0 D > < 0 x 0 A >
< B L U E > - - > ( 9 8 : D 3 : 3 1 : F 7 : 5 3 : 2 E ) $ P M T K T S X 1 , 1 1 5 8 2 4 , - 5 3 3 2 1 . 3 1 4 , 4 5 . 4 6 8 , 4 4 . 0 9 1 , 4 d 5 c 0 0 0 0 , - 5 . 3 2 4 6 7 8 , - 5 . 3 3 2 1 3 1 , - 0 . 4 5 2 8 6 3 , - 0 . 1 9 9 3 3 7 , 1 . 4 9 5 6 9 7 , - 5 . 3 3 2 , 1 . 0 * 5 0 < 0 x 0 D > < 0 x 0 A >
< G R E E N > ( ) $ P M T K E R T , 8 6 9 2 6 0 5 3 , 1 1 5 8 2 4 , 8 6 9 2 5 9 6 2 , 0 0 0 0 * 4 2 < 0 x 0 D > < 0 x 0 A >
< B L U E > - - > ( 9 8 : D 3 : 3 1 : F 7 : 5 3 : 2 E ) $ P M T K E R T , 8 6 9 2 6 0 5 3 , 1 1 5 8 2 4 , 8 6 9 2 5 9 6 2 , 0 0 0 0 * 4 2 < 0 x 0 D > < 0 x 0 A >
< G R E E N > ( ) $ P M T K E R T , 8 6 9 2 6 0 5 3 , 1 1 5 8 2 4 , 8 6 9 2 5 9 6 2 , 0 0 0 0 * 4 2 < 0 x 0 D > < 0 x 0 A >
< B L U E > - - > ( 9 8 : D 3 : 3 1 : F 7 : 5 3 : 2 E ) $ P M T K E R T , 8 6 9 2 6 0 5 3 , 1 1 5 8 2 4 , 8 6 9 2 5 9 6 2 , 0 0 0 0 * 4 2 < 0 x 0 D > < 0 x 0 A >

[Hakan]

Gerg M..
The NMEA Debug copy above are not NMEA 0183 sentences. Reading the manual for a ST1000 there are two data stream connections on the cable. One pair for SeaTalk and one pair for NME0183. Did you use the correct pair, NMEA+ NMEA-, to your RS232 adapter?


Also it seems your serial connection in OCPN use the output connection to send all received data. The blue (out) is the same as green (in).
To transfer route data to a AP you need to use a filter. See more here

[stevead]

It is NMEA 0183, just that it's proprietary Raymarine sentences. (Eg. $PMTKAGC)

If it was Seatalk, it would be unreadable binary.

And the (98: D3: 31: F7: 53: 2E) looks very much like the bluetooth (RFCOMM) hw address.

I see two problems, one as Hakan alludes to, is that you need to set up a filter. At present you are merely echoing the received data.
Filter out the proprietary sentences PMTKAGC, PMTKTSX1, PMTKERT and GNACCURACY

Secondly, there are no useful NMEA 0183 sentences being sent (or for that matter received). According to the manual the ST1000 requires at least the following:
Navigating to a waypoint, APB, RMB, XTE
Wind mode VWR (which I think is deprecated in most modern instruments with MWV)

From OpenCPN have you activated a route or waypoint ? That needs to be done in order for APB, RMB and XTE sentences to be generated.

Also begs the question, is your tablet configured to receive NMEA 0183 data from other sources?

[Greg M]

Many thanks Håkan. Yes, I am connected to NMEA+ NMEA-. It works flawlessly with OpenCPN and ST1000 on my notebook computer. My main problem is lack of knowledge, sorry.
The debug window on my notebook also shows the output connection sends all received data unchanged, so I presumed that was normal and I'm not aware of any filters in use.
I will study the information you have provided in the link to see if I can better understand what needs to be done.
Thanks again.
Greg

[Greg M]

Thanks stevead, In answer to your last two questions, when I captured that debug data, I was on the water and was on a route, swapping between my notebook and the tablet. The notebook worked, the tablet didn't. I am using the tablet's internal GPS, so perhaps that is not putting out the required data stream. Perhaps I should connect my external Globalsat BU-353N5 GPS puck to the tablet??
Yes, the "98: D3: 31: F7: 53: 2E" is the BT/RS232 that is based on the Bolutek BC04-B module.
Thanks to the advice from you and and Håkan I will investigate how to go about applying the necessary filters.

Greg