GY-85_Raspberry-Pi

Interfacing GY-85 (IMU module) with Raspberry Pi 3b+

Step 1: Updating python version

• Open terminal and write:

  $ sudo apt-get install python3-dev libffi-dev libssl-dev -y
  $ wget https://www.python.org/ftp/python/3.6.3/Python-3.6.3.tar.xz
  $ tar xJf Python-3.6.3.tar.xz
  $ cd Python-3.6.3
  $ ./configure
  $ make
  $ sudo make install
  $ sudo pip3 install --upgrade pip
  $ sudo nano ~/.bashrc
  $ alias python3=python3.6
  $ source ~/.bashrc
  

• To check if python has successfully upgraded, write the following lines in terminal:

  $ python3
  $ print("fhd-codes")
  

  (if the message is printed on the terminal, you have python3 installed now.)

• Close the terminal

Step 2: Enabling i2c on Raspberry Pi

• Goto the following directory: /etc/modules-load.d/

• Open "modules.conf" file and write i2c-dev in the end and save the file

• After that, open the following file: /etc/modprobe.d/raspi-blacklist.conf

• Comment the line (by adding # in the start) that says blacklist i2c-bcm2708 and save the file

  If the file is empty, leave it as it is

• Open terminal and enter these lines:

  $ sudo apt-get update && sudo apt-get install i2c-tools    
  $ sudo adduser USER i2c       
  

  (write username in place of USER which is 'pi' by default)

• Update the boot file by:

  $ sudo nano /boot/config.txt
  

  write the following lines in the end:

  dtparam=i2c_arm=on
  dtparam=i2c1=on
  

  Press Ctrl+X. Then press Y and hit Enter

Step 3: Installing quick2wire library

• Install git by writing following lines in terminal:

  $ sudo apt-get install git
  

• Download quick2wire API by:

  $ git clone https://github.com/quick2wire/quick2wire-python-api.git
  

• Now, we need to enable Python to access this APi. Open ~/.profile and add the following line in the end:

  export PYTHONPATH=$PYTHONPATH:$HOME/quick2wire-python-api

  replace $PYTHONPATH with the path where python is installed; and $HOME with the path where your downloaded API is stored.

  For example, in my case, it is: export PYTHONPATH=/home/pi/Python-3.6.3:/home/pi/quick2wire-python-api

  NOTE: ~/ is the slang for directory /home/pi/. The .profile file will be hidden, so make the hidden files visible first.

  Save and close the file

• Reboot your Raspberry Pi

  $ sudo reboot
  

Step 4: Connecting GY-85 and checking the connection

• Connect GY-85 with Raspberry Pi.

  Connect 3.3v, GND, SCL, SDA pins on GY-85 with the same pins on Raspberry Pi

• Open terminal and write:

  $ sudo i2cdetect -y 1
  

  where 1 is the port number for newer version of Raspberry Pi. If you're using older model of Raspberry Pi, write 0 instead.

  A table will appear which will show the address of connected devices. The sensors have following addresses:

  Accelerometer(ADXL): 53

  Gyroscope(ITG): 68

  Compass(HMC): 1e (if you see some other address for digital compass, note it down. It is explained in later section below)

Step 5: Downloading the code files

• Open the terminal and download the code files

  $ git clone https://github.com/fhd-codes/GY-85_Raspberry-Pi.git
  

Getting the values from Gyro, Acc, and Compass

• Run the following files to get the data:

  gyroTest.py

  accTest.py

  compassTest.py

  Note: If the output from compassTest.py is giving 0 values, it means that GY-85 module has QMC5883l instead of HMC5883l. And you might be getting 0d instead of 1e as address in Step 4. Special thanks to this source from where I figured out the right problem. If this this your case, download the following library:

  $ git clone https://github.com/RigacciOrg/py-qmc5883l.git
  

  Open the folder and run setup.py one time. Run qmcTest.py instead of compassTest.py, and you will start seeing the values.

  Kudos!! The data is being acquired form GY-85 module.

Main reference sources:

• Code is collected from these sources, and edited by me to make it compatible for Raspberry pi 3b+

  source1

  source2

  source3

  source4