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getting nmea0183 from a NASAMarine Duet
#1
I believe the NASAMarine Duet is the cheapest combined log/depth sounder around but when I ordered it, I quickly found out that it has a major disadvantage: it does not share it's data with other systems, there is no nmea output.
Not content with that, I hacked into the system and added just that, by dropping a tiny Atmega 32U4 board into the case, connecting it to the signal pins for chirp/echo and speed and putting together a quick sketch to wrap it all into valid nmea sentences.


If someone is interested, I can show a bit more of the build

here's the code with very basic documentation: https://github.com/pljakobs/NASAMarineDuetDriver
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#2
thanks for sharing!
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#3
This is very interesting, thank you. Do you think the NASA Depth Gauge works the same way (obvs without the log!)?

I've been trying to build an NMEA output using the secondary gauge connection as described here but the code is much more complicated (not helped by there being no code repository and the code in the atricle being affected by formatting and html escapes. I've built the module and yet to get it to work successfully, not helped by having limited access to the boat due to Covid lockdowns.
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#4
(2021-01-13, 09:22 PM)Phil_Shotton Wrote: This is very interesting, thank you. Do you think the NASA Depth Gauge works the same way (obvs without the log!)?

I've been trying to build an NMEA output using the secondary gauge connection as described here but the code is much more complicated (not helped by there being no code repository and the code in the atricle being affected by formatting and html escapes. I've built the module and yet to get it to work successfully, not helped by having limited access to the boat due to Covid lockdowns.

I have used the sketch off the page you linked. I had to copy it to a plaintext editor and then into arduinoIDE and check all the formatting to get it to work, but here's the sketch I'm successfully running on an Arduino Nano to interface my OpenPlotter build to by NASA Clipper Depth. To get it working on OpenPlotter I also had to enable the depth sentences in the Signal K to NMEA 0183 plugin. My guess is Signal K must have been misinterpreting or dumping the sentences in the conversion to SK before the data got to OpenCPN, now it doesn't touch them and just forwards the NMEA data.
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#5
(2021-01-01, 09:30 PM)pjakobs Wrote: I believe the NASAMarine Duet is the cheapest combined log/depth sounder around but when I ordered it, I quickly found out that it has a major disadvantage: it does not share it's data with other systems, there is no nmea output.
Not content with that, I hacked into the system and added just that, by dropping a tiny Atmega 32U4 board into the case, connecting it to the signal pins for chirp/echo and speed and putting together a quick sketch to wrap it all into valid nmea sentences.


If someone is interested, I can show a bit more of the build

here's the code with very basic documentation: https://github.com/pljakobs/NASAMarineDuetDriver

Thanks for sharing this, cool project.
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#6
This is fantastic. Can you let us know how you connected the arduino to the clipper duet. Did you connect it to the instrument directly or intercept the transducer signals

Thanks
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#7
Hi, is this thread for those Duets having a connection for a second display?
I realised this weekend, that my Duet doesn´t have a DIN-socket for another display and now I am wondering if I have to open it and solder it or if I have to forget the idea to get NMEA from it?
If it should be possible with that device, could I have a bit more support, on how to do it?

Thanks
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