This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
NMEA to Analog Pulse Conversion
Hi all,
Just an idea I wanted to kick around. I was reading this blog concerning the issues around paddlewheel logs. This has a vague relation to OpenPlotter in that I suppose something like this might someday find its way into build.

Down the page he mentions a NMEA to pulse converter - basically something that fools your knotmeter into thinking it's getting pulses from a paddlewheel, when actually it is getting input from GPS. It reads the NMEA string, and generates the appropriate frequency of pulses to simulate speed, albeit SOG instead of STW.

Leaving aside for a moment the issues around sometimes actually *wanting* real speed through the water in order to detect currents, this seems like an interesting idea. In my case, my speed transducer doesn't have a valve, so pulling it to clean it usually means lots of water and subsequent cleanup.

Soooo, being a big fan of Arduino, it seems to me that creating such a converter would be relatively straightforward - you simply use the Tone library to generate the appropriate frequency of square wave, after reading $GPRMC NMEA strings. Of course, some sort of interface would then be needed to interface to the knotmeter.

Am I missing something?

Forum Jump:

Users browsing this thread: 1 Guest(s)