A demo showing the pose of the GY-85 9DoF IMU sensor in 3D using esp-idf.

GY-85 consists of the following three chips.

• ADXL345 Accelermter
• ITG3205 Gyroscope
• QMC5883L Electronic Compass

You can use the Kalman filter to estimate the Euler angle.
Euler angles are roll, pitch and yaw.
It's very intuitive and easy to understand.

First, calibrate the compass and find the offset value for each axis.
As you can see, the X, Y and Z axes are quite off-center.

Then use the sensor values to find the Euler angles.

I used this library.

ESP-IDF V4.4/V5.x.
ESP-IDF V5.0 is required when using ESP32-C2.
ESP-IDF V5.1 is required when using ESP32-C6.

GY-85 9DoF IMU Sensors.

(*1)You can change it to any pin using menuconfig.

git clone https://github.com/nopnop2002/esp-idf-gy85
cd esp-idf-gy85/calibrate
idf.py set-target {esp32/esp32s2/esp32s3/esp32c2/esp32c3/esp32c6}
idf.py menuconfig
idf.py flash

To find the offset value, set the compass offset to 0.

ESP32 acts as a web server.
I used this component.
This component can communicate directly with the browser.
It's a great job.
Enter the following in the address bar of your web browser.

http:://{IP of ESP32}/
or
http://esp32.local/

As you rotate the IMU it plots the X, Y and Z values.
X, Y, Z offset are displayed.

If you set the offset you got from the calibration and run it again, the circle position will change.

git clone https://github.com/nopnop2002/esp-idf-gy85
cd esp-idf-gy85/euler
idf.py set-target {esp32/esp32s2/esp32s3/esp32c2/esp32c3}
idf.py menuconfig
idf.py flash

Sets the compass offset obtained by calibration.

ESP32 acts as a web server.
I used this component.
This component can communicate directly with the browser.
It's a great job.
Enter the following in the address bar of your web browser.

http:://{IP of ESP32}/
or
http://esp32.local/

WEB pages are stored in the html folder.
I used this for gauge display.
I used this for 3D display.
You can change it as you like.

You can view Euler angles using this tool.
It works as a UDP display server.
This is a great application.

+-------------+     +-------------+     +-------------+
|     IMU     | i2c |    ESP32    | UDP | pyteapot.py |
|             |---->|             |---->|             |
|             |     |             |     |             |
+-------------+     +-------------+     +-------------+

$ sudo apt install python3-pip python3-setuptools
$ python3 -m pip install -U pip
$ python3 -m pip install pygame
$ python3 -m pip install PyOpenGL PyOpenGL_accelerate
$ git clone https://github.com/thecountoftuscany/PyTeapot-Quaternion-Euler-cube-rotation
$ cd PyTeapot-Quaternion-Euler-cube-rotation
$ python3 pyteapot.py

The posture of your sensor is displayed.