Making Things Talk

282 MAKING THINGS TALK

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void getRMC(String[] data) {

// move the items from the string into the variables:

int time = int(data[1]);

// first two digits of the time are hours:

hrs = time/10000;

// second two digits of the time are minutes:

mins = (time%10000)/100;

// last two digits of the time are seconds:

secs = (time%100);

The serialEvent() method gets any

incoming data as usual, and passes it

off to a method called parseString().

That method splits the incoming string

into all the parts of the GPS sentence.

If it’s a GPRMC sentence, it passes it to

a method, getRMC() to handle it. If you

were writing a more universal parser,

you’d write similar methods for each

type of sentence.

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The getRMC() method converts

the latitude, longitude, and other

numerical parts of the sentence into

numbers.

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The draw() method prints the

readings in the window, and calls

another method, drawArrow() to draw

the arrow and circle.

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void draw() {

background(0);

// make the text white:

fill(255);

// print the date and time from the GPS sentence:

text(thisMonth+ "/"+ thisDay+ "/"+ thisYear , 50, 30);

text(hrs+ ":"+ mins+ ":"+ secs + " GMT ", 50, 50);

// print the position from the GPS sentence:

text(latitude + " " + northSouth + ", " +longitude +" "+ eastWest,

50, 70);

text("heading " + heading + " degrees", 50,90);

// draw an arrow using the heading:

drawArrow(heading);

}

void