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Other potential components
Other potential components
* Compass Module HM55B http://www.hobbyengineering.com/specs/PX-29123.pdf
* SCF5740 Siemens (OSRAM) 4 digit display http://catalog.osram-os.com/media/_en/Graphics/00034126_0.pdf
* SCF5740 Siemens (OSRAM) 4 digit display http://catalog.osram-os.com/media/_en/Graphics/00034126_0.pdf
* 0.96" OLED Display https://www.adafruit.com/products/684
* 0.96" OLED Display https://www.adafruit.com/products/684
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== Schematic ==
== Schematic ==
[[File:CompassSchematic.jpg|600px]]
[[File:CompassSchematic.jpg|600px]]
''Indicates wiring for [[RGBpixel]] LEDs, as opposed to [[ShiftBrite]]''


== Code ==
== Code ==
The following will give a compass heading via serial monitor with the CMPS03
The following will give a compass heading via serial monitor


<pre>
<pre>
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}
}
</pre>
</pre>
This code will provide x/y magnetic strength and computed angle with the HM55B
<pre>
/*
/////////////////////////////////
Htachi HM55B Compass
parallax (#)
AUTHOR:  kiilo kiilo@kiilo.org
License:  http://creativecommons.org/licenses/by-nc-sa/2.5/ch/
http://parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/txtSearch/hm55b/List/1/ProductID/98/Default.aspx?SortField=ProductName%2cProductName
http://sage.medienkunst.ch/tiki-index.php?page=HowTo_Arduino_Parallax_HM55B_Kompass
http://playground.arduino.cc/HM55B
/////////////////////////////////
*/
#include <math.h> // (no semicolon)
//// VARS
byte CLK_pin = 8;
byte EN_pin = 9;
byte DIO_pin = 10;
int X_Data = 0;
int Y_Data = 0;
int angle;
//// FUNCTIONS
void ShiftOut(int Value, int BitsCount) {
  for(int i = BitsCount; i >= 0; i--) {
    digitalWrite(CLK_pin, LOW);
    if ((Value & 1 << i) == ( 1 << i)) {
      digitalWrite(DIO_pin, HIGH);
      //Serial.print("1");
    }
    else {
      digitalWrite(DIO_pin, LOW);
      //Serial.print("0");
    }
    digitalWrite(CLK_pin, HIGH);
    delayMicroseconds(1);
  }
//Serial.print(" ");
}
int ShiftIn(int BitsCount) {
  int ShiftIn_result;
    ShiftIn_result = 0;
    pinMode(DIO_pin, INPUT);
    for(int i = BitsCount; i >= 0; i--) {
      digitalWrite(CLK_pin, HIGH);
      delayMicroseconds(1);
      if (digitalRead(DIO_pin) == HIGH) {
        ShiftIn_result = (ShiftIn_result << 1) + 1;
        //Serial.print("x");
      }
      else {
        ShiftIn_result = (ShiftIn_result << 1) + 0;
        //Serial.print("_");
      }
      digitalWrite(CLK_pin, LOW);
      delayMicroseconds(1);
    }
  //Serial.print(":");
// below is difficult to understand:
// if bit 11 is Set the value is negative
// the representation of negative values you
// have to add B11111000 in the upper Byte of
// the integer.
// see: http://en.wikipedia.org/wiki/Two%27s_complement
  if ((ShiftIn_result & 1 << 11) == 1 << 11) {
    ShiftIn_result = (B11111000 << 8) | ShiftIn_result;
  }
  return ShiftIn_result;
}
void HM55B_Reset() {
  pinMode(DIO_pin, OUTPUT);
  digitalWrite(EN_pin, LOW);
  ShiftOut(B0000, 3);
  digitalWrite(EN_pin, HIGH);
}
void HM55B_StartMeasurementCommand() {
  pinMode(DIO_pin, OUTPUT);
  digitalWrite(EN_pin, LOW);
  ShiftOut(B1000, 3);
  digitalWrite(EN_pin, HIGH);
}
int HM55B_ReadCommand() {
  int result = 0;
  pinMode(DIO_pin, OUTPUT);
  digitalWrite(EN_pin, LOW);
  ShiftOut(B1100, 3);
  result = ShiftIn(3);
  return result;
}
void setup() {
  Serial.begin(9600);
  pinMode(EN_pin, OUTPUT);
  pinMode(CLK_pin, OUTPUT);
  pinMode(DIO_pin, INPUT);
  HM55B_Reset();
}
void loop() {
  HM55B_StartMeasurementCommand(); // necessary!!
  delay(40); // the data is 40ms later ready
  Serial.print(HM55B_ReadCommand()); // read data and print Status
  Serial.print(" "); 
  X_Data = ShiftIn(11); // Field strength in X
  Y_Data = ShiftIn(11); // and Y direction
  Serial.print(X_Data); // print X strength
  Serial.print(" ");
  Serial.print(Y_Data); // print Y strength
  Serial.print(" ");
  digitalWrite(EN_pin, HIGH); // ok deselect chip
  angle = 180 * (atan2(-1 * Y_Data , X_Data) / M_PI); // angle is atan( -y/x) !!!
  Serial.print(angle); // print angle
  Serial.println("");
}
</pre>
See also: [[Compass_Vibro_Anklet]]
[[Category:Fort]]
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