YAPP: Homemade Seatalk stuff

AngusMcDoon

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Yet Another Pointless Project...

The weather is absolutely dire in Poofelly, so time to get the soldering iron out for some more Angustronics! Last time I did this I got shouted at for my electronic shortcomings by professional engineers, so I'm ready to be told off again :)

This time I've knocked up some stuff that listens in on the Seatalk bus for windspeed (no shortage today), wind direction, heading, COG and SOG from which with some sums it's possible to work out true wind speed and direction relative to the ground and not just the boat, i.e. taking into account boat movement and tide.

I average this stuff over 1 minute and 6 minutes and store it - an hour's sample for the former and a day's sample for the latter. Then I can plot it all again to give a log of what the true wind was doing over the last hour and day - wind direction at the top and speed at the bottom. Some photos attached. There are 3 views - 1 hour plot, 24 hour plot and data. Touching the screen changes between the views.

There's a bit of level changing stuff to get Seatalk signals inverted and down to 3.3V and opto-isolated (the little Veroboard at the side). Then it goes into a PIC18F26K22 processor buried in all the brown spaghetti. The display is QVGA touch 18 bit colour from a mobile phone. It needs 2 voltage levels which is a bit of a nuisance, hence the scattering of transistors on the side (all I had in my bits box to do it with). No OS on the processor, just a bare app and some drivers. It's powered from the programmer at the moment (the black lozenge) but I'll get it powered from the Seatalk bus when I've got some regliators.

At the moment the time axis is just labelled with fixed values for 1 hour or 1 day. I've noticed that time is available on Seatalk as well, so I'll update the labels to have real time values.

I've also got a atmospheric pressure sensor. I'll add that as well but I've run out of pins on the 18F26K22 so I'll get a 18F46K22 going sometime.

Cost of the bits was about £3, display £11. If anyone's interested in the source or schematic let me know. Thanks to Thomas Knauf for making Seatalk information available...

http://www.thomasknauf.de/seatalk.htm

Some picture explanation:
Apparent wind angle is read from Seatalk, it was just being updated when I took the photo of the data screen.
Pink graph is windspeed on the bottom half in knots over 24 hours, direction in degrees true at top.
Blue graph is the same but over the last hour.
 
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trapezeartist

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A Pointless Project indeed. If you have data coming from Seatalk, I assume you have a Raymarine plotter. Which means you just have to display "Ground Wind" on your plotter, which is Raymarine-speak for true "true wind".
 

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Fantastic!!! A thing of great beauty, must have been exciting seeing it working for the first time.

Where did you get the screen from?
 

FullCircle

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I love stuff like this. Brilliant.
I cant do it myself, but I spent all yesterday afternoon sorting my NMEA network. It was bad enough doing it with proprietary boxes and a heap of wiring manuals.
My hat is off to you Mr McDoon!!:)
 

AngusMcDoon

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A Pointless Project indeed. If you have data coming from Seatalk, I assume you have a Raymarine plotter. Which means you just have to display "Ground Wind" on your plotter, which is Raymarine-speak for true "true wind".

I have a Raymarine plotter, but there's no such thing as Ground Wind on mine. Is it a new thing as mine is quite old? My ST60 display shows true wind, but that's relative to the water, not ground. Will the display show a 24 hour history?

There's no requirement to have a Raymarine plotter to have wind and GPS data on the Seatalk bus. It's generated at the instruments, not the plotter.
 
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AngusMcDoon

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aluijten

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Nothing pointless about it. If you now put the lot in a nice enclosure you've saved yourself an expensive instrument from Rayarine and gained a lot of understanding on how this stuff works. Good show!
If you put some additional efforts into the software you could build your own polar graph generator. It would build up the statistics for different wind angles, speed, course, etc. and plot a polar graph for your boat.
 

AngusMcDoon

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If you put some additional efforts into the software you could build your own polar graph generator. It would build up the statistics for different wind angles, speed, course, etc. and plot a polar graph for your boat.


That was YAPP number 1 years ago!

I'm sure I posted about it on here but I can't find it now. It was running on a Symbian phone with NMEA data coming in the phone's serial port having been converted from Seatalk by a Seatalk/NMEA bridge by Frank Wallenwein.

The data could then be downloaded to a PC for analysis and plotting. All I've got left are some pictures and all the source code (if anyone wants it). It ran on a Sony Ericsson P900/P910 UIQ phone. UIQ is long dead so it's not much use any more.
 

AngusMcDoon

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Version 2 today - now reading the time from Seatalk and plotting the time grid as real time rather than relative time. Seatalk time is GMT only though. Date is available too, but how do you figure out when BST starts and ends from the date - anyone know?
 

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From here...

http://iteadstudio.com/store/index.php?main_page=product_info&cPath=3&products_id=55

although I see that the price has gone up a bit now to £14. They provide driver source code for an Arduino which I ported to the 18F PIC. Also their touch driver is slightly incorrect. If anyone wants the PIC driver source code, let me know.

Thanks for the link, looks like an interesting site. i got an arduino recently, lots to learn. Shame there isn't a cheap specific gravity sensor, being able to constantly watch the SG of each cell of your batts would be so cool.
 

AngusMcDoon

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If you turn it into a kit I will buy it!

You can have all the source code and schematic if you like and make it up on Veroboard. I can flash a processor with the software if you don't have the kit to do it. I need to draw out the schematic though, and finish off the power supply bit. It's a bit fiddly wiring up the display - 40 connections.
 

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Slightly related question - have you found a way of displaying serial data on laptop beyond a scrolling terminal emulator? Never played with a pic so don't even know if they do that but the arduino can output data to a comm port. I tried getting excel to do it but couldn't get mscomm to work in visual basic. Anyone found a way? Only screen i have at the mo is the laptop.
ta
 

nimbusgb

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How would you display it apart from a scrolling display?

I did once write a GPS NMEA analyser that watched for certain sentences and ticked a box every time it saw one you wanted and then timed out after a preset period ( 5 s )

Anything beyond that is an instrument display :)
 

Conachair

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How would you display it apart from a scrolling display?

I did once write a GPS NMEA analyser that watched for certain sentences and ticked a box every time it saw one you wanted and then timed out after a preset period ( 5 s )

Anything beyond that is an instrument display :)

If i could get excel to read the serial port then either average the numbers out a bit in the arduino or excel and display in a cell or textbox, rather than have a thousand numbers falling off the bottom of the screen. Forgotten the original reason for this but now it's REALLY important to get it working :confused::confused:
 

AngusMcDoon

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Slightly related question - have you found a way of displaying serial data on laptop beyond a scrolling terminal emulator?
I tried getting excel to do it but couldn't get mscomm to work in visual basic.

I've got VB6 kicking around somewhere and years ago did some apps that used the mscomm object successfully. AFAIR you just drop one on your form, set your parameters, open it, and read away. You can easily compare bytes 4-6 of an NMEA message if that is what you are receiving and when you get a match display the message somewhere on the form.

Come to think of it, I got it to work in the free version of C# as well.

Never played with a pic so don't even know if they do that...

If an Arduino does it, there will be a PIC that does it - at a quarter of the price and 4 times the bother :)

but the arduino can output data to a comm port

The PIC18F26K22 has 2 UARTs on chip - geekspeak for comm port. More can be simulated if required.

I've never used serial stuff in XL, so don't know if it can do it.

If i could get excel to read the serial port then either average the numbers out a bit in the arduino or excel and display in a cell or textbox

That's exactly what my windy app here is doing, except the source data comes from Seatalk instead of RS232 serial.
 

Conachair

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AFAIR you just drop one on your form, set your parameters, open it, and read away.

Apparently there was an update which messed everything up, I get an error message "the object is not trusted.... " so can't get it to drop on the form. Several hundred google links later still can't get it to work. One shall continue... :rolleyes:
All good fun though.
 
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