Distance calculation using BR355 GPS & NOKIA 6100 Color Display

Page last updated 18 Oct 2013, by Brandon Lico. 0 replies

Introduction

This project has the mbed use a BR-355 GPS and a Nokia 6100 LCD to record and display distance moved. A device such as this is very practical in airplanes, automobiles and could even be used for bikers/runners.

Description

  • Once the project is started up a menu gives two options, button 1 (s1) for coordinates and button 2 (s2) for distance.
  • If button 1 is pressed, the GPS coordinates are updated and displayed on the LCD every second.
  • If button 2 is pressed, a second menu is displayed, giving two options: button 1 for Start/Stop and button 2 to reset recording.
    • Once recording of distance starts, the updated distance is displayed on the LCD every 5 seconds.
    • Button 1 can be held down while distance is being calculated to pause distance calculation.
    • Button 2 can be pressed to reset the distance calculation.
  • The third push-button (the one not on the LCD) can be pressed at any time to return to the first menu.
  • If the GPS can not find coordinates the LCD will display "No Lock"

Hardware

  1. mbed
  2. BR-355 GPS Module
  3. Sparkfun Nokia 6100 Color LCD Breakout Board
  4. RS-232 Breakout Board
  5. PS/2 Breakout Board
  6. push button

Connections

/media/uploads/brandonlico/imag0210.png

Nokia 6100 LCDMbed
VBATTVV = 5V
3.3VVout (3.3.V)
GndGnd
Resetp12
DIOp5
SCKp7
CSp11
S2p27
S1p28

Note

The LCD's on board push-buttons (S1 and S2) are used, but any standard push-button's could be used.

PS/2Mbed
VccVV=5V
GndGnd
RS-232Mbed
VccVV = 5V
GndGnd
TXp10
RXp9

Information

You might need to use a mini gender changer and NULL modem with Sparkfun RS-232 breakout. Also, depending on the RS-232 model, wiring RX may or may not be required, even if you aren't using it.

Code

The following API's were used with this code:

Distance Calculation Info:

main.cpp

#include "mbed.h"
#include "GPS.h"
#include "NokiaLCD.h"
#include <math.h>
#define PI 3.14159265

NokiaLCD lcd(p5, p7, p11, p12, NokiaLCD::LCD6610); // mosi, sclk, cs, rst, type
GPS gps(p9, p10);
DigitalIn pb1(p28);
DigitalIn pb2(p27);
DigitalIn pbReset(p26);



void setup();

void coordinates()
{

    while(1) {
        //if reset pressed return to menu
        if (!pbReset) {
            setup();
        }
        lcd.cls();
        lcd.locate(0,3);
        //display coordinates every 1 second
        if(gps.sample()) {
            lcd.printf("Location at %f, %f", gps.longitude, gps.latitude);

        } else {
            lcd.printf("No Lock");
        }
        wait(1);
    }

}

void distance()
{
    float dist = 0;
    float lat2 = 0;
    float lon2 = 0;
    float lat1 = 0;
    float lon1 = 0;
    float dLat = 0;
    float dLon = 0;
    float c = 0;
    float a = 0;
    float d = 0;
    lcd.cls();
    lcd.locate(0,3);
    lcd.printf("1 : Start/Stop");
    lcd.locate(0,5);
    lcd.printf("2 : Reset Recording");
    wait(1);
    //Wait for buttons to be pressed
    while( pb2 && pb1 && pbReset) {
    }
    wait(.001);
    if (!pbReset) {
        setup();
    }
    if (!pb2) {
        distance();
    }
    if (!pb1) {
        //Sample First Value
        if (gps.sample()) {
            lat1 = gps.latitude;
            lon1 = gps.longitude;
            lcd.cls();
            lcd.locate(0,3);
            lcd.printf("Signal Locked");
            wait(5);
            // Begin Calculating Distance
            while(1) {
                // Return to menu if reset pushed
                if (!pbReset) {
                    setup();
                }
                // Reset Distance Calculation if pb2 pushed
                if (!pb2) {
                    distance();
                }
                // Stop Recording while pb1 is pushed
                while(!pb1) {
                    lcd.locate(0,3);
                    lcd.printf("Stopped");
                    wait(.3);
                }


                //Sample Second Value
                if (gps.sample()) {
                    lat2 = gps.latitude;
                    lon2 = gps.longitude;
                }

                //Calculate Distance
                dLat = (lat2-lat1)*(PI/180);
                dLon = (lon2-lon1)*(PI/180);
                a = sin(dLat/2) * sin(dLat/2) +
                    sin(dLon/2) * sin(dLon/2) * cos(lat1*(PI/180)) * cos(lat2*(PI/180));
                c = 2 * atan2(sqrt(a), sqrt(1-a));
                d = 6371000 * c;

                //GPS is only precise to 5 meters, so throw out bad data
                if ( d <= 5) {
                    d = 0;
                }
                dist = dist + d;
                lcd.cls();
                lcd.locate(0,3);
                lcd.printf("Distance Moved: %f", dist);
                lat1 = lat2;
                lon1 = lon2;

                //Sample Every 5 Seconds
                wait(5);
            }
        } else {
            lcd.cls();
            lcd.locate(0,3);
            lcd.printf("No lock");
            wait(3);
            distance();
        }

    }
}

void setup()
{
    //Main Menu
    lcd.background(0x0000FF);
    lcd.cls();
    lcd.locate(0,3);
    lcd.printf("1 : Coordinates");
    lcd.locate(0,5);
    lcd.printf("2 : Distance");
    lcd.locate(0,7);
    lcd.printf("Reset for menu");
    while( pb2 && pb1) {
    }
    wait(.001);
    if (!pb1) {
        coordinates();

    }
    if (!pb2) {
        distance();
    }
    lcd.cls();
}

int main()
{
    pb2.mode(PullUp);
    pb1.mode(PullUp);
    pbReset.mode(PullUp);
    setup();
}

Video

Troubleshooting!

The BR-355 may not work inside buildings, and get's best reception in open areas. Also, the GPS is only accurate to about 5 meters, therefore if you are moving slower than 1 meter per second, your movement may not be added to the displayed distance.

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