Compass Magnetic Electronic 3-Axis Module GY-271 HMC5883L

Features

• 3-axis magnetic field sensing for accurate heading detection
• Compact size, suitable for space-constrained projects
• Digital I2C interface for easy microcontroller integration
• High sensitivity for low-field magnetic measurements
• Ideal for robotics, UAVs, and navigation applications

Specifications

Pinout

• VCC: Power supply (3V to 5V)
• GND: Ground
• SCL: I2C Clock
• SDA: I2C Data
• DRDY (Data Ready): Goes LOW for ~250µs when new data is available (internally pulled up)

How to Be Used:

• Connect the module to your microcontroller using the I2C interface.
• Supply power to the module through the VCC and GND pins (3V–5V supported).
• Connect SDA to the microcontroller’s I2C data pin and SCL to the I2C clock pin.
• Upload the example code to initialize the HMC5883L and read magnetic field data.
• Place the module away from strong magnetic sources (motors, speakers, metal frames) for accurate readings.
• Use the X and Y axis data to calculate heading (compass direction) in degrees.

Connections (Arduino Uno)

Library Requirement

• Install Adafruit HMC5883 Unified library from the Arduino Library Manager.
• Also ensure the Adafruit Unified Sensor library is installed.

Example Code (Arduino)

#include "Wire.h"
#include "Adafruit_Sensor.h"
#include "Adafruit_HMC5883_U.h"

Adafruit_HMC5883_Unified mag = Adafruit_HMC5883_Unified(12345);

void setup() {
  Serial.begin(9600);
  Wire.begin();

  if (!mag.begin()) {
    Serial.println("HMC5883L not detected!");
    while (1);
  }
}

void loop() {
  sensors_event_t event;
  mag.getEvent(&event);

  float heading = atan2(event.magnetic.y, event.magnetic.x);
  heading = heading * 180 / PI;

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

  Serial.print("Heading: ");
  Serial.print(heading);
  Serial.println(" degrees");

  delay(500);
}

Code Explanation

• Initializes I2C communication and the HMC5883L sensor.
• Reads magnetic field data from X and Y axes.
• Calculates compass heading using arctangent math.
• Converts the heading value into degrees (0°–360°).
• Outputs the heading to the Serial Monitor.

Applications

• Digital compass and navigation systems
• Robotics orientation and heading control
• UAV and drone stabilization
• Direction sensing in embedded systems