Digital Compass Display with Arduino: A Beginner’s Guide to Navigation Systems

Objective
The objective of this Digital Compass Display with Arduino project is to help beginners create a digital compass using a magnetometer sensor and Arduino. This project introduces navigation, Arduino programming, and sensor integration.

Project Goal for Digital Compass Display with Arduino

• Learn to interface a magnetometer sensor (e.g., HMC5883L) with Arduino.
• Understand how to measure magnetic fields and determine directions.
• Build a basic digital compass that displays directional headings on an LCD.

Requirement Components for Digital Compass Display with Arduino

Here is the list of components needed to build the Digital Compass Display with Arduino:

1. Arduino Uno — Buy on Amazon
2. HMC5883L Magnetometer Sensor — Buy on Amazon
3. 16x2 LCD Display with I2C Module — Buy on Amazon
4. Breadboard — Buy on Amazon
5. Jumper Wires — Buy on Amazon
6. USB Cable — Buy on Amazon

Sensor Basics for Digital Compass Display with Arduino

What is an HMC5883L Magnetometer Sensor?
The HMC5883L magnetometer is a sensor that measures the strength and direction of magnetic fields. It is widely used for navigation and orientation in electronic compasses, robotic systems, and smartphones.

How Does the HMC5883L Work?

• The HMC5883L detects magnetic field components in the X, Y, and Z axes.
• It communicates with Arduino using the I2C protocol, providing directional data that can be converted to a compass heading.

Pinout of HMC5883L Magnetometer Sensor

• The HMC5883L has four main pins:
• VCC: Connects to the 3.3V or 5V pin on Arduino.
• GND: Connects to the GND pin on Arduino.
• SDA: Connects to the SDA pin on Arduino (A4 on Uno).
• SCL: Connects to the SCL pin on Arduino (A5 on Uno).

Sensor Real-Life Applications

• Navigation Systems: Provides directional data for GPS and navigation devices.
• Robotics: Helps robots determine orientation for pathfinding.
• Smartphones: Used in built-in compasses for outdoor activities.
• Aerospace Systems: Assists in directional control and orientation of aircraft.

Circuit Connection for Digital Compass Display with Arduino

1. Connect the Arduino Uno: Use the USB cable to connect the Arduino Uno to your computer.
2. Connect the HMC5883L Magnetometer Sensor:

• Connect the VCC pin of the HMC5883L to the 3.3V or 5V pin on Arduino.
• Connect the GND pin of the HMC5883L to the GND pin on Arduino.
• Connect the SDA pin of the HMC5883L to the A4 (SDA) pin on Arduino.
• Connect the SCL pin of the HMC5883L to the A5 (SCL) pin on Arduino.

1. Connect the 16x2 LCD with I2C Module:

• Connect the VCC of the LCD to the 5V pin on Arduino.
• Connect the GND of the LCD to the GND pin on Arduino.
• Connect the SDA pin of the LCD to the A4 (SDA) pin on Arduino.
• Connect the SCL pin of the LCD to the A5 (SCL) pin on Arduino.

Circuit Connection Analysis: How the Digital Compass Works

• The HMC5883L magnetometer measures the Earth’s magnetic field and provides raw X, Y, and Z-axis data to the Arduino.
• The Arduino processes this data to calculate the heading angle in degrees.
• The 16x2 LCD displays the calculated heading, indicating the compass direction (e.g., North, East, South, West).

Safety Tips for Digital Compass Display with Arduino

• Avoid placing the magnetometer near strong magnetic fields or electronic devices to maintain accuracy.
• Handle the sensor carefully to prevent damage to its sensitive components.
• Disconnect the power supply when making or modifying circuit connections.

Arduino Programming Section for Digital Compass Display with Arduino

Arduino Syntax

• Wire.begin(); — Starts the I2C communication.
• lcd.print(text); — Displays text on the LCD.
• heading = atan2(y, x); — Calculates the heading angle using X and Y magnetic field components.
• if (condition) { } — Executes code if the condition is true.

Arduino Code for Digital Compass Display with Arduino

Before using this code, install the HMC5883L and LiquidCrystal_I2C libraries in the Arduino IDE by going to ‘Sketch’ > ‘Include Library’ > ‘Manage Libraries’, then search for “HMC5883L” and “LiquidCrystal_I2C” and install them.

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <HMC5883L.h>

HMC5883L compass; // Create HMC5883L object
LiquidCrystal_I2C lcd(0x27, 16, 2); // Set LCD address to 0x27 for a 16x2 display

void setup() {
  Wire.begin(); // Start I2C communication
  lcd.begin(); // Initialize the LCD
  lcd.backlight(); // Turn on the LCD backlight
  lcd.setCursor(0, 0);
  lcd.print("Digital Compass");
  delay(2000); // Wait for 2 seconds
  lcd.clear();

  compass = HMC5883L(); // Initialize the magnetometer

  if (!compass.begin()) {
    lcd.print("Error init");
    while (1); // Stop if the magnetometer is not connected
  }

  compass.setRange(HMC5883L_RANGE_1_3GA); // Set sensor range
}

void loop() {
  Vector mag = compass.readRaw(); // Read raw magnetic field data
  float heading = atan2(mag.YAxis, mag.XAxis); // Calculate heading angle

  // Convert heading from radians to degrees
  float headingDegrees = heading * 180.0 / M_PI;
  if (headingDegrees < 0) {
    headingDegrees += 360.0; // Adjust for negative angles
  }

  // Display heading on LCD
  lcd.setCursor(0, 0);
  lcd.print("Heading:");
  lcd.setCursor(0, 1);
  lcd.print(headingDegrees);
  lcd.print(" deg");

  delay(1000); // Update every second
}

Steps to Upload Code for Digital Compass Display with Arduino

1. Open the Arduino IDE on your computer.
2. Connect the Arduino Uno using the USB cable.
3. Install the HMC5883L and LiquidCrystal_I2C Libraries: Go to ‘Sketch’ > ‘Include Library’ > ‘Manage Libraries’, search for “HMC5883L” and “LiquidCrystal_I2C”, and install them.
4. Select the Board: Go to ‘Tools’ > ‘Board’ > ‘Arduino Uno’.
5. Select the Port: Go to ‘Tools’ > ‘Port’ and select the correct port.
6. Upload the Code: Copy the code above, paste it into the IDE, and click ‘Upload’.

Check Output of Digital Compass Display with Arduino

After uploading the code, the 16x2 LCD will display the compass heading in degrees. Rotate the sensor slowly and observe the changing heading values, which should correspond to the compass directions.

Code Explanation for Digital Compass Display with Arduino

• compass.readRaw();: Reads the raw magnetic field data from the HMC5883L sensor.
• atan2(mag.YAxis, mag.XAxis);: Calculates the heading angle using X and Y-axis values.
• if (headingDegrees < 0): Adjusts for negative angles by adding 360 degrees.
• lcd.print(headingDegrees);: Displays the calculated heading in degrees on the LCD.

Troubleshooting Tips for Digital Compass Display with Arduino

• No response from the HMC5883L sensor? Check the sensor connections and ensure it is correctly connected to the Arduino.
• Incorrect heading values? Make sure the sensor is not near magnetic or metallic objects.
• No display on LCD? Verify the I2C address and connections.
• Code not uploading? Confirm the correct board and port settings in the Arduino IDE.

Suggestion for Beginners

Book Recommendation

For a comprehensive guide on Arduino programming, I recommend Arduino Programming for Absolute Beginners. This book covers projects like the Digital Compass Display, offering clear instructions and practical examples.