YAPP proposal for Seatalk to NMEA0183

Keith-i

Keith-i

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I'm an avid fan of homebrew solutions to technical problems and am really impressed with Angus' altruistic support to our communication woes. What I'd really like though is an economic and simple converter to get basic data off an original Seatalk network and onto NMEA0183. I realise there are commercial options out there, but they are rather a lot of money for a 'nice to have' item and I really don't need the guaranteed reliability and product support that they will come with.

I'm wondering whether there are enough other interested bods, that we might be able to persuade Angus to make a simple converter box. My requirements would be for heading, and depth to be converted one way but I'm sure once the electronics are in place it will just be down to programming for any additional data fields. In my particular case I have a Raymaire autopilot and depth sounder sitting alongside a Garmin plotter setup. The A/P has a NMEA output but it only parses heading data and few other less relevant bits of info. I'd like to get the depth onto my Garmin if I could.

Make a post if you're interested please!
 
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I've never done it as I don't have anything that produces or uses NMEA0183 on my boat apart from my BR-355 GPS mouse and my DSC VHF. I'm happy to do it if...

1) There's enough interest
2) People let me know what messages they are interested in
3) Somone can test it on their boat
 
Hi. I'm sure that Angus is a little tongue in cheek about Frank being a competitor. Frank (and Angus) has been very helpful and friendly to me but he does produce similar devices (I don't think it is his core business though as he appears to have an engineering firm). PM me if I'm wrong.

Re the possible SeaTalk to NMEA YAPP, I'm happy to help if it is of any use, although all my coding is in BASIC and is completely amateurish - but I might be able to test stuff. (I now have PIC programming capabilities and am happy to buy any bits I'd need this end (eg PIC, header etc).

I claim to, sort-of, understand NMEA (0183) and SeaTalk and can send and read both from a PC (but not a PIC).

It is not hard to compose and send NMEA (0183) messages, including checksum, from one serial port and to do the SeaTalk stuff (in C if you must) on another serial/USB port (or for Angus, on a PIC).

I do have my chartplotter and my instruments on my workbench but lack any transducers (ie no wind, depth, temp or compass - I can feed in a GPS). I get around this by sending NMEA sentences from the PC to the Chartplotter (Raymarine SL631) which then sends to the SeaTalk network. I'm now able to send NMEA, recieve SeaTalk and plot all that I need on a PC or via WiFi to an iPhone/iPad - but not on a PIC as you will want.
Let me know if you'd like my input. Regards,

Andrew
 
Just to sort of close this thread, from the lack of responses it doesn't look like I can muster any interest in such a convertor. I suppose foolishly I may have narrowed the field a bit too much by proposing a NMEA0183 conversion, whereas N2K would be just as dandy, if not better - I had assumed that 183 would be easier to achieve.
 
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> Andrew wrote :
> I'm sure that Angus is a little tongue in cheek about Frank being a competitor.

I hope so too ;-)


> Keith-i wrote :
> But not British

Well - too bad. Sorry about that. ;-)
But there is not very much I can do about it. :-)

> Nigel wrote :
> here are details of one at the site below, but I know nothing about this type of microcontroller.

The older bridges have/had an AtMega32 processor. An ATMEL chip with 32 kB main memory and not too much RAM.
The newer bridges have an AtMega1284P or AtMega128. Needed more space for new functions
( Autopilot remote control, calculation of true wind heading/speed, better Display etc. )

Software is written in pure C.

To AngusMcDoon and Keith-I : just let me know if I can help in any way ?
I guess you know, the sources are still available if you like .....


btw. I've started to play with SeaTalk <-> N2K.
Really just started. I can read and write can messages,
I can read things like depth, position, speed from N2K -
but sending and properly announcing my device on the N2K bus is not working.

btw. I just bought an NMEA Windspeed and direction masthead unit. British product, purchased in Britain :-)
Looks interesting .... http://www.gadgetpool.de/nuke/modules.php?name=News&file=article&sid=44
 
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G'day Frank. I wasn't aware you were looking on - just as well I havn't said anything too negative . . .
Thanks to your (and Angus') help my project has progressed so that I can send and recieve SeaTalk (TM Raymarine) and show it on a PC, iPad or iPhone as a list of numbers (eg beside OpenCPN), as graphs (eg depth or temperature over time) and operate as a remote autopilot - with pretty much full AP control - all via WiFi. It also determines where the hotest and coolest water temperature occured and gives the time, Lat & Lon - important when dealing with the EAC of up to 4kts of southbound hot water. It saves data in CSV and GPX format so it can be plotted in OpenCPN etc, showing all temperatures allong your track. I'm pretty happy with it.

Keep up the good work, Andrew.
 
Hi Nigel,

well - in the past I sent my sources only on request.
I just thought it's nice to be in e-mail contact with the other users of the sources.


The schematics of the bridge are available as "eagle" files.
But I have to admit, it's not obvious where to find them.

Well - I guess I just move the sources and schematics to some place, where they are easier to find.

Frank
 
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