Any help you can provide would be great!!

Thank you
Dave Pina

Now the only issue is that my robot zigs and zags threw a parking lot, but never heads towards the target, infact over all I would say it heads away from it.

What steps did you take to over come this? I have gone so far as to try my code on a pre 1.0 version of the Arduino IDE. I had heard that Arduino 15 used hardware for servo, but getting it to work has proven to be pain.

-Jim

#include
#include
#undef abs
#undef round
int wpt = 0;
float dest_latitude;
float dest_longitude;
NMEA gps(GPRMC); // GPS data connection to GPRMC sentence type

/* BEGIN EDITABLE CONSTANTS SECTION */

//These define the positions for your steering servo
#define CENTER_SERVO 95
#define MAX_LEFT_SERVO 85
#define MAX_RIGHT_SERVO 108

//Speed Controller
#define STOP_SPEED 90
#define FORWARD_SPEED 120
#define REVERSE_SPEED 70
#define TURN_SPEED 100

//When the car is within this range (meters), move to the next waypoint
#define WPT_IN_RANGE_M 12

/* DEFINE GPS WPTS HERE – Create more cases as needed */
void trackWpts() {
switch(wpt) {
case 0:
dest_latitude = 32.298927;
dest_longitude = -90.212195;
break;
case 1:
dest_latitude = 32.298977;
dest_longitude = -90.213118;
break;
case 2:
dest_latitude = 32.299848;
dest_longitude = 90.213407;
default:
dest_latitude = 0;
dest_longitude = 0;
break;
}
if (gps.gprmc_distance_to(dest_latitude,dest_longitude,MTR) 0 ) {
char c = Serial.read();

if (gps.decode(c)) {

// check if GPS positioning was active
if (gps.gprmc_status() == ‘A’) {
// calculate relative direction to destination
dir = gps.gprmc_course_to(dest_latitude, dest_longitude) – gps.gprmc_course();

if (dir 180)
dir -= 360;

if (dir 75)
hardRight();
else
driveToTarget();

}
else //No GPS Fix…Wait for signal
stop();

}
}
}
else
stop();
}

void driveStraight() {
steering.write(CENTER_SERVO);
speeed.write(FORWARD_SPEED);
Serial.println(“Driving straight…”);
}

void driveToTarget() {
servo_pos = map(dir, -75, 75, MAX_LEFT_SERVO, MAX_RIGHT_SERVO);
steering.write(servo_pos);
speeed.write(FORWARD_SPEED);
Serial.print(“Driving at “);
Serial.print(dir);
Serial.print(“. – “);
Serial.print(gps.gprmc_distance_to(dest_latitude,dest_longitude,MTR));
Serial.print(“m to go”);
Serial.print(“\n”);
}

void hardLeft() {
steering.write(MAX_LEFT_SERVO);
speeed.write(TURN_SPEED);
Serial.print(“Driving hard left. – “);
Serial.print(gps.gprmc_distance_to(dest_latitude,dest_longitude,MTR));
Serial.print(“m to go”);
Serial.print(“\n”);
}

void hardRight() {
steering.write(MAX_RIGHT_SERVO);
speeed.write(TURN_SPEED);
Serial.print(“Driving hard right. – “);
Serial.print(gps.gprmc_distance_to(dest_latitude,dest_longitude,MTR));
Serial.print(“m to go”);
Serial.print(“\n”);
}

void stop() {
steering.write(CENTER_SERVO);
speeed.write(STOP_SPEED);
Serial.print(“Stopped.”);
Serial.print(“\n”);
}

In that case you can just connect the signal line from the speed controller to another digital pin and create another Servo instance on that pin (very similar to how the steering Servo is setup). The Servo library allows you to send a value between 0-180 degrees. For a speed controller, 90 would typically be neutral, 0 full reverse, and 180 full forward.

Good luck!