Compass Using Indus Board

A compass is a device used for navigation and geographic orientation. It typically consists of a magnetized needle or another element, such as a compass card or compass rose, which can pivot to align itself with magnetic north.

In this project, we use Indus Board coin to make a compass. We program the board which uses accelerometer and magnetometer readings to calculate the heading of this compass.

Additionally, we use 4 LEDs which glows in the direction of compass, which are connected with four different pins of the Indus board.

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Components required

Schematic and Real Implementation

Arduino Code

 #include <Wire.h> 
#include <LSM303AGR_ACC_Sensor.h> 
#include <LSM303AGR_MAG_Sensor.h> 
#if defined(ARDUINO_SAM_DUE) 
#define DEV_I2C Wire1 //Define which I2C bus is used. Wire1 for the Arduino Due 
#define SerialPort Serial 
#else 
#define DEV_I2C Wire //Or Wire 
#define SerialPort Serial 
#endif 
// Components 
LSM303AGR_ACC_Sensor Acc(&DEV_I2C); 
LSM303AGR_MAG_Sensor Mag(&DEV_I2C); 
// Function prototypes 
float calculateHeading(int32_t magData[3], int32_t accData[3]); 
const int ledPin_n = 1; 
const int ledPin_e = 2; 
const int ledPin_s = 3; 
const int ledPin_w = 4; 
void setup() { 
// Initialize the LEDs 
pinMode(ledPin_n, OUTPUT); 
pinMode(ledPin_e, OUTPUT); 
pinMode(ledPin_s, OUTPUT); 
pinMode(ledPin_w, OUTPUT); 
// Initialize serial communication 
SerialPort.begin(115200); 
// Initialize I2C communication 
DEV_I2C.begin(); 
// Initialize the accelerometer and magnetometer 
if (Acc.begin() != 0) { 
SerialPort.println("Failed to initialize LSM303AGR accelerometer!"); 
while (1); 
} 
if (Mag.begin() != 0) { 
SerialPort.println("Failed to initialize LSM303AGR magnetometer!"); 
while (1); 
} 
// Enable the sensors 
Acc.Enable(); 
Acc.EnableTemperatureSensor(); 
Mag.Enable(); 
} 
void loop() { 
// Read accelerometer data 
int32_t accData[3]; 
Acc.GetAxes(accData); 
// Read temperature 
float temperature; 
Acc.GetTemperature(&temperature); 
// Read magnetometer data 
int32_t magData[3]; 
Mag.GetAxes(magData); 
// Calculate the heading 
float heading = calculateHeading(magData, accData); 
SerialPort.print("Heading: "); 
SerialPort.print(heading, 3); 
if((0<=heading and 20>=heading) or (340<=heading and 360>=heading)){ 
SerialPort.print(" NORTH"); 
digitalWrite(ledPin_n, HIGH); // pin 1 
digitalWrite(ledPin_w, LOW); // pin 4 
digitalWrite(ledPin_s, LOW); // pin 3 
digitalWrite(ledPin_e, LOW); // pin 2 
} 
else if(70<=heading and 110>=heading){ 
SerialPort.print(" WEST"); 
digitalWrite(ledPin_w, HIGH); // pin 4 
digitalWrite(ledPin_s, LOW); // pin 3 
digitalWrite(ledPin_e, LOW); // pin 2 
digitalWrite(ledPin_n, LOW); // pin 1 
} 
else if(160<=heading and 200>=heading){ 
SerialPort.print(" SOUTH"); 
digitalWrite(ledPin_s, HIGH); // pin 3 
digitalWrite(ledPin_e, LOW); // pin 2 
digitalWrite(ledPin_w, LOW); // pin 4 
digitalWrite(ledPin_n, LOW); // pin 1 
} 
else if(250<=heading and 290>=heading){ 
SerialPort.print(" EAST"); 
digitalWrite(ledPin_e, HIGH); // pin 2 
digitalWrite(ledPin_n, LOW); // pin 1 
digitalWrite(ledPin_w, LOW); // pin 4 
digitalWrite(ledPin_s, LOW); // pin 3 
} 
else if(20.01<=heading and 69.99>=heading){ 
SerialPort.print(" NORTH-WEST"); 
digitalWrite(ledPin_n, HIGH); // pin 1 
digitalWrite(ledPin_w, HIGH); // pin 4 
digitalWrite(ledPin_s, LOW); // pin 3 
digitalWrite(ledPin_e, LOW); // pin 2 
} 
else if(110.01<=heading and 159.99>=heading){ 
SerialPort.print(" SOUTH-WEST"); 
digitalWrite(ledPin_n, LOW); // pin 1 
digitalWrite(ledPin_w, HIGH); // pin 4 
digitalWrite(ledPin_s, HIGH); // pin 3 
digitalWrite(ledPin_e, LOW); // pin 2 
} 
else if(200.01<=heading and 249.99>=heading){ 
SerialPort.print(" SOUTH-EAST"); 
digitalWrite(ledPin_n, LOW); // pin 1 
digitalWrite(ledPin_w, LOW); // pin 4 
digitalWrite(ledPin_s, HIGH); // pin 3 
digitalWrite(ledPin_e, HIGH); // pin 2 
} 
else if(290.01<=heading and 339.99>=heading){ 
SerialPort.print(" NORTH-EAST"); 
digitalWrite(ledPin_n, HIGH); // pin 1 
digitalWrite(ledPin_w, LOW); // pin 4 
digitalWrite(ledPin_s, LOW); // pin 3 
digitalWrite(ledPin_e, HIGH); // pin 2 
} 
Serial.println(); 
// SerialPort.println(" degrees |"); 
delay(10); // Adjust delay as needed 
} 
float calculateHeading(int32_t magData[3], int32_t accData[3]) { 
// Calculate tilt compensation 
float pitch = atan2(accData[1], sqrt(sq(accData[0]) + sq(accData[2]))); 
float roll = atan2(-accData[0], accData[2]); 
// Tilt compensation 
float xh = magData[0] * cos(pitch) + magData[2] * sin(pitch); 
float yh = magData[0] * sin(roll) * sin(pitch) + magData[1] * cos(roll) - magData[2] * sin(roll) * cos(pitch); 
// Calculate heading in degrees 
float heading = atan2(yh, xh) * 180 / PI; 
// Normalize heading to 0-360 degrees 
if (heading < 0) { 
heading += 360; 
} 
return heading; 
} 

Author(s): Manjeet Vishwakarma,  Abhay Verma and Satywanti Kundu are B.Tech ECE students at GJUS&T HISAR