compass.ino

/*
  ChronoLCD Color - An example sketch for the Color LCD Shield Library
  by: Jim Lindblom
  license: CC-BY SA 3.0 - Creative commons share-alike 3.0
  use this code however you'd like, just keep this license and
  attribute. Let me know if you make hugely, awesome, great changes.

  This sketch draws an analog and digital clock on the Color LCD
  Shield. You can also use the on-board buttons to set the hours
  and minutes.

  Use the defines at the top of the code to set the initial time.
  You can also adjust the size and color of the clock.

  To set the time, first hit S3. Then use S1 and S2 to adjust the
  hours and minutes respsectively. Hit S3 to start the clock
  back up.

  This example code should give you a good idea of how to use
  the setCircle, setLine, and setStr functions of the Color LCD
  Shield Library.
*/
#include <ColorLCDShield.h>
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_LSM303_U.h>

#define CIRCLE_RADIUS 50  // radius of clock face
#define CIRCLE_CENTER 55  // If you adjust the radius, you'll probably want to adjust this
#define S_LENGTH  48  // length of compass hand
#define Q_LENGTH  40  // length of arrow hand

#define BACKGROUND  BLACK  // room for growth, adjust the background color according to daylight
#define C_COLOR  RED  // This is the color of the circle
#define S_COLOR  YELLOW  // compass hand color
#define Q_COLOR  GREEN   // qibla hand color
#define T_COLOR  RED     // text color;

LCDShield lcd;

Adafruit_LSM303_Mag_Unified mag = Adafruit_LSM303_Mag_Unified(12345);
bool magSetup = false;
void setup()
{
  pinMode(10, OUTPUT);
  analogWrite(10, 1023); //PWM control blacklight
  /* Initialize the LCD, set the contrast, clear the screen */
  lcd.init(PHILLIPS);
  lcd.contrast(40);
  lcd.clear(BACKGROUND);

  magSetup = mag.begin();


  drawCompass();  // Draw the compass face, this includes N, E, S, W
  drawCompassHands();  // Draw the compass hands
}

void loop()
{
  delay(250);
  /* Once each 250 milliseconds, we'll redraw the compass with new values */
  drawCompass();
  drawCompassHands();
}

/*
  drawCompass() simply draws the outer circle of the compass, and 'N',
  'E', 'S', and 'W'.
*/
void drawCompass()
{
  /* Draw the circle */
  lcd.setCircle(CIRCLE_CENTER, 66, CIRCLE_RADIUS, C_COLOR);

  /* Print 12, 3, 6, 9, a lot of arbitrary values are used here
     for the coordinates. Just used trial and error to get them
     into a nice position. */
  lcd.setStr("E", CIRCLE_CENTER - CIRCLE_RADIUS, 66-9, C_COLOR, BACKGROUND);
  lcd.setStr("S", CIRCLE_CENTER - 9, 66 + CIRCLE_RADIUS - 12, C_COLOR, BACKGROUND);
  lcd.setStr("W", CIRCLE_CENTER + CIRCLE_RADIUS - 18, 66-4, C_COLOR, BACKGROUND);
  lcd.setStr("N", CIRCLE_CENTER - 9, 66 - CIRCLE_RADIUS + 4, C_COLOR, BACKGROUND);
}

/*
  drawCompassHands() draws the compas and qibla hands in their proper
  position. Room for growth here, I'd like to make the compass hands
  arrow shaped, or at least thicker and more visible.
*/
void drawCompassHands()
{
  static int sx, sy,qx,qy;

  /* Delete old lines: */
  lcd.setLine(CIRCLE_CENTER, 66, CIRCLE_CENTER+sx, 66+sy, BACKGROUND);  // delete second hand
  lcd.setLine(CIRCLE_CENTER, 66, CIRCLE_CENTER+qx, 66+qy, BACKGROUND);  // delete qibla hand

  /* Get a new sensor event */
  sensors_event_t event;
  mag.getEvent(&event);

  float Pi = 3.14159;

  // Calculate the angle of the vector y,x
  float heading = -(atan2(event.magnetic.y,event.magnetic.x) * 180) / Pi - 180;

  float nth = (atan2(event.magnetic.y,event.magnetic.x) * 180) / Pi;

  // Normalize to 0-360
  if (heading < 0)
  {
    heading = 360 + heading;
  }

  if (nth < 0)
  {
    nth = nth + 360;
  }

  /* Calculate and draw new lines: */
  s = heading;  // map the 0-60, to "360 degrees"

  sx = S_LENGTH * sin(3.14 * ((double) s)/180);  // woo trig!
  sy = S_LENGTH * cos(3.14 * ((double) s)/180);  // woo trig!
  qx = Q_LENGTH * sin(3.14 * ((double) s + 225)/180);  // woo trig!
  qy = Q_LENGTH * cos(3.14 * ((double) s + 225)/180);  // woo trig!

  lcd.setLine(CIRCLE_CENTER, 66, CIRCLE_CENTER+sx, 66+sy, S_COLOR);  // print second hand
  lcd.setLine(CIRCLE_CENTER, 66, CIRCLE_CENTER+qx, 66+qy, M_COLOR);
  char angle[10];
  dtostrf(nth, 8, 1, angle);
  lcd.setStr(angle, CIRCLE_CENTER + CIRCLE_RADIUS + 4, 22, C_COLOR, BACKGROUND);
}