Welcome to gadgetPool.de!
gadgetPool
Homepage
Projekt veröffentlichen
Artikel schreiben
Projekte lesen
Artikel lesen
Forum
Diskussionen Ideen Vorschläge
Downloads
Treiber Dateien Datenblätter
Anmeldung
Passwort Mail Einstellungen

     Menue
WebShop
Hier gibt's die gadgets

     Languages
Sprache für das Interface auswählen

English German

     Login
Benutzername

Passwort

Kostenlos registrieren!. Gestalten Sie Ihr eigenes Erscheinungsbild. Passen Sie das Seitenlayout Ihren Wünschen an

gadgetPool.de: Forum

gadgetPool.de :: View topic - Can I receive True Wind Dir?
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log inLog in 

Can I receive True Wind Dir?

 
Post new topic   Reply to topic    gadgetPool.de Forum Index -> Seatalk NMEA Bridge
View previous topic :: View next topic  
Author Message
jsoler
Newbie
Newbie


Joined: Feb 03, 2009
Posts: 3

PostPosted: Wed May 20, 2009 2:32 pm    Post subject: Can I receive True Wind Dir? Reply with quote

Hi,
I have a Seatalk NMEA Bridge, can I receive TWD instead Apparente Wind Angle?

Thanks.
Back to top
View user's profile Send private message
FWallenwein
Site Admin
Site Admin


Joined: Mar 26, 2006
Posts: 419
Location: Mannheim / Germany

PostPosted: Thu May 21, 2009 9:46 am    Post subject: Reply with quote

Hi jsoler,

no, you can't. I don't know of any SeaTalk datagramm, that contains true wind direction. As far as I know, the Instruments don't send this type of data.

You can receive apparent wind direction and speed. With that your PC Progamm might be able to calcualte true wind speed - if there is any chart plotter software that does it.

Regards
Frank
Back to top
View user's profile Send private message Visit poster's website
tkoning
Newbie
Newbie


Joined: Mar 28, 2012
Posts: 2

PostPosted: Thu Apr 19, 2012 7:23 pm    Post subject: true wind Reply with quote

hi

is it possible to adapt the software to calculate True wind in the nmea_setalk bridge , if you have apparant wind and sog available ?

thx
dick koning
Back to top
View user's profile Send private message
FWallenwein
Site Admin
Site Admin


Joined: Mar 26, 2006
Posts: 419
Location: Mannheim / Germany

PostPosted: Thu Apr 19, 2012 8:05 pm    Post subject: Reply with quote

Well - I think `Yes`.
If someone really needs it, I could check if I can make it.
Takes some trigonometry, and there are no floating point calculations in the bridge
right now. I'm afraid it could consume too much memory. There is not much memory left in the bridge. But - it might be worth it to try and see how it goes.
The question is - do we need it ? Do you have a real application that needs true wind ? The bridge would build a true-wind-nmea sentence.......



Regards Frank
Back to top
View user's profile Send private message Visit poster's website
tkoning
Newbie
Newbie


Joined: Mar 28, 2012
Posts: 2

PostPosted: Thu Apr 19, 2012 8:30 pm    Post subject: Reply with quote

FWallenwein wrote:
Well - I think `Yes`.
If someone really needs it, I could check if I can make it.
Takes some trigonometry, and there are no floating point calculations in the bridge
right now. I'm afraid it could consume too much memory. There is not much memory left in the bridge. But - it might be worth it to try and see how it goes.
The question is - do we need it ? Do you have a real application that needs true wind ? The bridge would build a true-wind-nmea sentence.......



Regards Frank

hi

i am not sure
i use the bridge to merge infomation from my st60 wind and tridata instruments with garmin gps information
The merged data is send to my PC running waypointgps (www.waypointgps.nl) plotting software
The software shows a true wind arrow but the direction is al wrong
(other seatalk data like depth and windspeed is correct)

i will do some more experimenting and will let you know
do you have suggestions of things to try ?

dick koning
Back to top
View user's profile Send private message
jferguson
Master
Master


Joined: May 20, 2011
Posts: 17
Location: US East Coast

PostPosted: Sun Apr 22, 2012 9:23 pm    Post subject: Reply with quote

Dick,
I'm building a device to show present position, true wind, heading, wind speed, depth, and distance and bearing to a fix. The device will feed an LCD display over my head in the berth and should help me in the event of serious wind and the possibility of anchor dragging. Idea is that if I'm awakened by high-wind alarm, I'll be able to look at distance an bearing to the fix i established when I retired and get a feeling for whether i am dragging. If I want, i can reset the fix from the buttons on the display and then see if I'm moving from that position.

Getting true wind direction on a stationary boat is easy - only need a compass signal and the signal from the seatalk wind transducer.

But a moving boat is harder. The RayMarine manual for our anemometer says that it only needs boatspeed to get true wind. I don't see how that could be enough. It seems to me that it also needs actual boat track and a compass signal. It could get the boat track from the GPS, and maybe the compass too. Do you have a SeaTalk compass?

john
Back to top
View user's profile Send private message
FWallenwein
Site Admin
Site Admin


Joined: Mar 26, 2006
Posts: 419
Location: Mannheim / Germany

PostPosted: Mon Apr 23, 2012 10:08 am    Post subject: Reply with quote

Hello jferguson,

"True-wind" and "apparent wind" are not related to a Magnetic or GPS direction direction of the wind.

True wind and apparent wind direction are both relative to the boat.

True wind is the wind speed and direction you would experiece if the boat would stand still. If the wind came right from the front, the wind instrument would show a direction of 0 deg. No matter what compass direction your boat has.
The wind direction is just realted to the boat.

Apparent wind is "the wind you feel" when standing on your boat while it is moving. It's a combination of "true wind" and boat speed.
But again - relative to the boat, not to a GPS or compass heading.


Regards
Frank
Back to top
View user's profile Send private message Visit poster's website
jferguson
Master
Master


Joined: May 20, 2011
Posts: 17
Location: US East Coast

PostPosted: Mon Apr 23, 2012 9:29 pm    Post subject: Reply with quote

I see. I had thought the term meant wind direction relative to north. so what i wrote earlier was based on that mistake. my system will show compass wind direction, but that is because i want to easily compare what is happening to the forecast.

sorry if i caused any confusion Sad
Back to top
View user's profile Send private message
FWallenwein
Site Admin
Site Admin


Joined: Mar 26, 2006
Posts: 419
Location: Mannheim / Germany

PostPosted: Mon Apr 23, 2012 9:58 pm    Post subject: Reply with quote

No worries.
I always thought it is kind of strange to call it "true wind",
and refere to wind relative to the boat.
Took me quite a while to find out, what Raymarine ment when they say 'true'.
I'm not sure if the term 'true wind direction' is used like this everywhere.
But anyway - my sailing teacher used it the same way, so I guess it's right Smile


Frank..
Back to top
View user's profile Send private message Visit poster's website
FWallenwein
Site Admin
Site Admin


Joined: Mar 26, 2006
Posts: 419
Location: Mannheim / Germany

PostPosted: Sun Dec 30, 2012 2:02 pm    Post subject: Reply with quote

Just an update.

Meanwhile I have moved the SeaTalk Nmea Bridge firmware to
a AtMega1284p processor.
It has 128kb memory - four times the memory in the Atmega32 chip normally used on the Bridge.

This AtMega1284p firmware also contains calcualtion for true wind.

CLICK HERE to see info more on the new chip
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    gadgetPool.de Forum Index -> Seatalk NMEA Bridge All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001-2003 phpBB Group
phpBB port v2.0.7 based on Tom Nitzschner's phpbb2.0.6 upgraded to phpBB 2.0.7 standalone was developed and tested by:
ChatServ, mikem,
and Paul Laudanski (aka Zhen-Xjell).

Version 2.0.7 by Nuke Cops © 2004 http://www.nukecops.com
Forums ©




All logos and trademarks in this site are property of their respective owner. The comments are property of their posters, all the rest © 2006-2015 by gadgetPool.


PHP-Nuke Copyright © 2005 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.
Erstellung der Seite: 0.05 Sekunden