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Permalink Reply by Bot Thoughts on August 16, 2012 at 10:27pm

Would TinyGPS be of use here?

I wrote a split() routine that is similar to C strtok() and perl split so that I could read in parameters from a config file:

http://mbed.org/users/shimniok/code/AVC_2012/file/826c6171fc1b/util.c

Examples of using split() here: 

http://mbed.org/users/shimniok/code/AVC_2012/file/826c6171fc1b/Conf...

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Permalink Reply by Justin on August 16, 2012 at 10:34pm

ive been looking at the tinyGPS code, but it doesnt seem to work for my use in my project.

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Permalink Reply by Bot Thoughts on August 16, 2012 at 10:49pm

Um, ok, sure. How about the code snippets I posted? Will those work?

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Permalink Reply by Justin on August 16, 2012 at 10:57pm

I havent tested it, but from what i can see, it looks fairly clear and i might use some of it (the split code).

thanks, although, is there any other possible suggestions you can think of how to do it? because im not the most fluent in programming, and i might struggle to get it working correctly.

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Permalink Reply by Bot Thoughts on August 19, 2012 at 8:49am

Well... now's a good time to learn :)  I think you'll be fine getting it to work. Just post more questions here and I'll do what I can to help.

What's the ultimate goal here? What are you working on? What are you trying to accomplish with the lat/lon parsing?

I need a little context to be able to help you a little better.

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Permalink Reply by Justin on August 19, 2012 at 11:51pm

Im building essentially an ardurover, but im using an 'offtheshelf' purchased arduino mega2560.

It includes a gps and compass... so what im trying to do by finding these lat and long values is mathematically work out heading and steer until the rover faces exactly the desired heading then accelerate. -resulting in basic navigation between two points.

So yeh, essentially the maths coding needs the values only of the
lat and long of its current location, extracted from the nmea string, to give bearing from current location to desired location.

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Permalink Reply by Bot Thoughts on August 20, 2012 at 7:20am

Ok, gotcha.

If you are programming using Arduino environment one option is to use TinyGPS. It parses NMEA output and you can then query lat/lon and ignore the rest.

Otherwise, you have to work out how to get the string into memory to parse, then run the parsing code to split it up. What I posted assumed the string was in memory already (which is a separate problem).

It's best to take baby steps, working on a tiny chunk of the problem at a time. Set a variable equal to a test string, then work on the function to parse it and return back lat and lon.

There's a lot to talk through to roll your own when you have minimal programming experience. Not sure if this is the right place to have that chat. So if you want we can talk through email: http://www.bot-thoughts.com/2007/01/contact-me.html

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Permalink Reply by Justin on August 21, 2012 at 8:11am

hi, just letting you know i got it working, and i have the exact value printing out on my serial connection. thanks

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