AngusMcDoon
Well-known member
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.
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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