{"id":2052,"date":"2021-08-04T10:43:36","date_gmt":"2021-08-04T08:43:36","guid":{"rendered":"https:\/\/dross.net\/aviation\/?page_id=2052"},"modified":"2023-06-17T08:33:50","modified_gmt":"2023-06-17T06:33:50","slug":"how-to-add-a-safe-shutdown-button-to-stratux","status":"publish","type":"page","link":"https:\/\/dross.net\/aviation\/how-to-and-where-to-start-with-stratux\/how-to-add-a-safe-shutdown-button-to-stratux\/","title":{"rendered":"How to add a safe shutdown button to Stratux (or Raspberry Pi)?"},"content":{"rendered":"

Overview<\/h2>\n
\n\t

Component List<\/a>
\nSet up Instructions<\/a>
\nInstall Firmware<\/a>
\nInstall FlightMap<\/a>
\nAdd shutdown button<\/a>
\nFlash a T-Beam<\/a>
\nFlash a T-Motion<\/a>
\nAltitude Sensor to T-Beam<\/a>
\nAltitude Sensor to T-Motion<\/a>
\nAdd AHRS Sensor<\/a>
\nUpgrade Stratux<\/a>
\nSubmit to OGN<\/a>
\nSupport needed?<\/a><\/p>\n<\/div>\n<\/div><\/div><\/div><\/div>

\n
\n\t

By default a Raspberry Pi and therefore a Stratux Flarm<\/a> does not have a physical switch to shut down the operating system. Just cutting the power of a Raspberry (or any computer) will result in RAM issues in the long term. Therefore, this section explains how we use a button which triggers the command to shut down a Raspberry Pi\/ Stratux safely.<\/p>\n

Since Python becomes more popular, we will use this programming language.<\/p>\n

\"Stratux
Enable Stratux firmware to support shutdown switch<\/figcaption><\/figure>\n

Buy your ready 2 fly Stratux Firmware SD card instead.<\/a><\/p>\n

\n

Pre-work to be done when using firmware version 026 or newer<\/h2>\n
    \n
  1. Since the firmware version 026<\/a> or newer does no longer allow to write logs to micro SD card, a quick change in the Stratux web interface (open your browser and type-in http:\/\/192.168.10.1\/<\/a>) > Settings > Diagnostics<\/a> is needed.<\/li>\n
  2. Go to Diagnostics and set \"persistent logging\" to enabled. this will allow us to modify the firmware.\n
    \"Stratux
    Stratux persistent logging: write logs to micro SD card instead of RAM<\/figcaption><\/figure>\n<\/li>\n
  3. follow steps below. Once the modifications to support a physical safe shutdown switch has been completed, change the persistent logging back to \"disabled\"<\/li>\n<\/ol>\n

    Use PUTTY to enable SSH connection to your Stratux\/ Raspberry Pi<\/h2>\n
      \n
    1. The operating system has already been flashed on a SD card<\/a>.<\/li>\n
    2. Download and install the latest version of PUTTY<\/a>, a client to enable SSH connection<\/li>\n
    3. Boot up your Stratux<\/li>\n
    4. Stratux' Wifi should appear in your Laptop's network section.<\/li>\n
    5. Execute PUTTY and use Stratux' default IP address as the Host Name: 192.168.10.1\n
      \"PUTTY
      PUTTY - enable SSH connection to Raspberry PI and Stratux (OGN) Flarm<\/figcaption><\/figure>\n<\/li>\n
    6. Use the Raspberry PI's standard username \"pi\" and password \"raspberry\"
      \nthe screen should look like the following:<\/p>\n
      \"PUTTY
      PUTTY SSH welcome page<\/figcaption><\/figure>\n
      \n

      highlight the source code below, go to PUTTY and right click to paste the code<\/strong><\/p>\n

      \n<\/li>\n<\/ol>\n

      Creating the shut down button support<\/h2>\n
        \n
      1. We create a folder which we name \"Scripts\".<\/li>\n
      2. Then a blank file named \"shutdown_pi.py\" gets created<\/li>\n
      3. we edit the file and fill-in content into it.
        \n(mark the code, click right in PUTTY console to paste the code, then press Enter)<\/p>\n
        mkdir Scripts  \ncd Scripts  \ntouch shutdown_pi.py\nnano shutdown_pi.py<\/pre>\n<\/li>\n
      4. Then fill-in the below code into the file:\n
        #!\/bin\/python  \n# Simple script for shutting down the raspberry Pi at the press of a button.  \n# by Inderpreet Singh, modified by Alexander Dross - Dross:Aviation \n\u00a0\nimport RPi.GPIO as GPIO  \nimport time  \nimport os  \n\u00a0\n# Use the Broadcom SOC Pin numbers  \n# Setup the Pin with Internal pullups enabled and PIN in reading mode.  \nGPIO.setmode(GPIO.BCM)  \nGPIO.setup(21, GPIO.IN, pull_up_down = GPIO.PUD_UP)  \n\u00a0\n# Our function on what to do when the button is pressed  \ndef Shutdown(channel):  \n    os.system(\"sudo shutdown -h now\")  \n\u00a0\n# Add our function to execute when the button pressed event happens  \nGPIO.add_event_detect(21, GPIO.FALLING, callback = Shutdown, bouncetime = 2000)  \n\u00a0\n# Now wait!  \nwhile 1:  \n    time.sleep(1)<\/pre>\n<\/li>\n
      5. Save the file by pressing CTRL+X then press y to confirm to overwrite and Enter<\/li>\n
      6. The Python script now tries to access GPIO Pin \u00a0GPIO pin 39 (Ground) and 40 (GPIO 21 \u2013 PCM_DOUT)<\/a><\/li>\n
      7. To test if the script works, please simply enter the following lines into PUTTY (again, mark the code, and do a right click in the console to paste)\n
        sudo python shutdown_pi.py<\/pre>\n<\/li>\n
      8. If the script works, you must close and re-open PUTTY again, by following steps 4. and 5.<\/li>\n
      9. Now we have to enable that the script runs automatically every time the Raspberry Pi\/ Stratux starts. Therefore we execute the following command:\n
        sudo nano \/etc\/rc.local<\/pre>\n<\/li>\n
      10. We need to add our python command before the last line which closes the if loop. Therefore, add the following line before the #fi at the end of the file:\n
        \"add
        add the following line before the #fi at the end of the file<\/figcaption><\/figure>\n
        sudo python \/home\/pi\/Scripts\/shutdown_pi.py &<\/pre>\n<\/li>\n
      11. Save the file by pressing CTRL+X and then y, Enter<\/li>\n
      12. go back to bullet point 2. -> Go to Diagnostics and set \"persistent logging\"<\/a> to disabled.<\/li>\n
      13. Connect the switch to GPIO pin 39 (Ground) and 40 (GPIO 21 \u2013 PCM_DOUT) and press it. The Stratux should now shutdown within 2 seconds.\n
        \"Connect
        Connect Shutdown Switch to Raspberry PI3B GPIO Pins<\/figcaption><\/figure>\n<\/li>\n<\/ol>\n
        \n