GY-87 10DOF Module MPU6050 HMC5883L BMP180 Sensor

GY-87 Module          →    Arduino Uno
─────────────────────────────────────────
VCC_IN (5V)           →    5V
GND                   →    GND
SCL                   →    A5 (SCL)
SDA                   →    A4 (SDA)

/*
  GY-87 10DOF Module – Complete Sensor Initialization with I2C Bypass
*/

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_MPU6050.h>
#include <Adafruit_HMC5883_U.h>
#include <Adafruit_BMP085.h>

// Create sensor objects
Adafruit_MPU6050 mpu;
Adafruit_HMC5883_Unified mag = Adafruit_HMC5883_Unified(12345);
Adafruit_BMP085 bmp;

void setup() {
  Serial.begin(115200);
  Wire.begin();
  
  // Initialize MPU6050 and enable I2C bypass mode
  if (!mpu.begin()) {
    Serial.println("Failed to find MPU6050 chip");
    while (1);
  }
  Serial.println("MPU6050 Found!");
  
  // CRITICAL: Enable I2C bypass mode to access HMC5883L
  // This allows the magnetometer on the auxiliary bus to be accessed directly
  mpu.setI2CBypassEnabled(true);
  
  // Now initialize the magnetometer (HMC5883L)
  if (!mag.begin()) {
    Serial.println("HMC5883L not found! Check I2C bypass configuration.");
    while (1);
  }
  Serial.println("HMC5883L Found!");
  
  // Initialize BMP180 barometer
  if (!bmp.begin()) {
    Serial.println("BMP180 not found!");
    while (1);
  }
  Serial.println("BMP180 Found!");
  
  Serial.println("GY-87 All Sensors Ready");
  Serial.println("-----------------------------");
}

void loop() {
  // Read MPU6050 (gyroscope + accelerometer)
  sensors_event_t a, g, temp;
  mpu.getEvent(&a, &g, &temp);
  
  // Read HMC5883L (magnetometer)
  sensors_event_t magEvent;
  mag.getEvent(&magEvent);
  
  // Calculate heading in degrees (0° = North)
  float heading = atan2(magEvent.magnetic.y, magEvent.magnetic.x);
  if (heading < 0) heading += 2 * PI;
  heading = heading * 180 / PI;
  
  // Read BMP180 (pressure and temperature)
  float temperature = bmp.readTemperature();
  float pressure = bmp.readPressure() / 100.0;  // Convert to hPa
  float altitude = bmp.readAltitude();
  
  // Display results
  Serial.print("Accel (m/s²): ");
  Serial.print(a.acceleration.x); Serial.print(", ");
  Serial.print(a.acceleration.y); Serial.print(", ");
  Serial.println(a.acceleration.z);
  
  Serial.print("Gyro (°/s): ");
  Serial.print(g.gyro.x); Serial.print(", ");
  Serial.print(g.gyro.y); Serial.print(", ");
  Serial.println(g.gyro.z);
  
  Serial.print("Heading: ");
  Serial.println(heading);
  
  Serial.print("Pressure: ");
  Serial.print(pressure);
  Serial.println(" hPa");
  
  Serial.print("Altitude: ");
  Serial.print(altitude);
  Serial.println(" m");
  
  Serial.println("-----------------------------");
  
  delay(500);
}

#include <Wire.h>
#include "I2Cdev.h"
#include "MPU6050.h"
#include "HMC5883L.h"

MPU6050 mpu;
HMC5883L mag;

void setup() {
  Wire.begin();
  Serial.begin(115200);
  
  // Initialize MPU6050
  mpu.initialize();
  
  // CRITICAL: Enable I2C bypass mode
  mpu.setI2CMasterModeEnabled(false);
  mpu.setI2CBypassEnabled(true);
  mpu.setSleepEnabled(false);
  
  // Now initialize magnetometer
  mag.initialize();
  
  Serial.println(mag.testConnection() ? "HMC5883L OK" : "HMC5883L ERROR");
}

mpu.setI2CMasterModeEnabled(false);
mpu.setI2CBypassEnabled(true);
mpu.setSleepEnabled(false);