Multi-Sensor Fusion Using Gyroscope and Accelerometer

Difficulty Level: Intermediate

This tutorial demonstrates how to perform sensor fusion using a gyroscope and an accelerometer with an ESP32. The aim is to calculate the orientation of the device more accurately by combining data from both sensors.

Required Components with eBay Links

• ESP32 Wroom32
• MPU6050 Gyro + Accelerometer
• Jumper Cables
• Breadboard
• USB-C Cable Red

Wiring the MPU6050

Connect the MPU6050 to the ESP32 as follows:

• MPU6050 VCC to ESP32 3.3V
• MPU6050 GND to ESP32 GND
• MPU6050 SDA to ESP32 GPIO 21
• MPU6050 SCL to ESP32 GPIO 22

Code Explanation

The following code reads data from the MPU6050 and combines the accelerometer and gyroscope data to compute the orientation of the device using complementary filtering.

Key Functions

• Wire.begin(): Initializes the I2C communication.
• mpu.initialize(): Initializes the MPU6050 sensor.
• mpu.getMotion6(): Reads the accelerometer and gyroscope data.
• atan2(): Computes the angle based on the accelerometer data.
• filter(): Applies complementary filtering to fuse the accelerometer and gyroscope data.

Arduino Code

Here’s the Arduino code for the multi-sensor fusion:

#include 
#include 

MPU6050 mpu;

float ax, ay, az; // Accelerometer readings
float gx, gy, gz; // Gyroscope readings
float angleX = 0, angleY = 0; // Angles
const float alpha = 0.98; // Complementary filter constant

void setup() {
  Serial.begin(115200);
  Wire.begin();
  mpu.initialize();
}

void loop() {
  mpu.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);

  // Convert accelerometer readings to angles
  float accelAngleX = atan2(ay, az) * 180 / PI;
  float accelAngleY = atan2(ax, az) * 180 / PI;

  // Complementary filter
  angleX = alpha * (angleX + gx * 0.01) + (1 - alpha) * accelAngleX;
  angleY = alpha * (angleY + gy * 0.01) + (1 - alpha) * accelAngleY;

  // Print the angles
  Serial.print("Angle X: "); Serial.print(angleX);
  Serial.print(" | Angle Y: "); Serial.println(angleY);
  
  delay(10);
}
            

Upload and Test

1. Connect your ESP32 to your computer using the USB cable.
2. Open the Arduino IDE and copy the code above into the editor.
3. Select your ESP32 board and the correct port in the IDE.
4. Click the upload button to send the code to the ESP32.
5. Open the Serial Monitor to view the calculated angles.

Conclusion

In this tutorial, you learned how to use a gyroscope and accelerometer to calculate the orientation of a device using sensor fusion techniques. The complementary filter combines the strengths of both sensors for accurate angle measurements.