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OctoPrint

This page describes steps for configuring OctoPrint on the Pi and using mjpg-streamer to stream video from a webcam to OctoPrint for the purposes of remote monitoring and recording timelapse videos of print jobs.

Install mjpg-streamer

The mjpg-streamer utility is an efficient way to stream video from various input devices (e.g., Raspberry Pi camera module or USB webcam) to various output devices (e.g., web browser). General operating system dependencies differ between Rasberry Pi OS and Ubuntu OS. See the note “If you’re planning to use OctoPrint for 3D printing…” in these pages for dependencies. Install the rest of mjpeg-streamer as follows:

git clone https://github.com/jacksonliam/mjpg-streamer.git
cd mjpg-streamer/mjpg-streamer-experimental/
export LD_LIBRARY_PATH=.
make

List connected video devices:

v4l2-ctl --list-devices

mmal service 16.1 (platform:bcm2835-v4l2):
	/dev/video2

WEB CAM: WEB CAM (usb-0000:01:00.0-1.1):
	/dev/video0
	/dev/video1
	/dev/media0

The first (connected to /dev/video2) is a Raspberry Pi camera module. The second (connected to /dev/video0) is a USB webcam.

To stream the Raspberry Pi camera module:

./mjpg_streamer -i "input_uvc.so -d /dev/video2 -fps 15" -o "output_http.so -p 8081 -w ./www"

Alternatively, to stream the USB webcam:

./mjpg_streamer -i "input_uvc.so -d /dev/video0 -fps 15" -o "./output_http.so -p 8081 -w ./www"

In both of the above:

Once the streamer is up and running, navigate to http://xxxx:8081/ for an overview or http://xxxx:8081/?action=stream for a dedicated stream (where xxxx is the IP address of the Raspberry Pi).

It can happen that a process is holding a /dev/video* device, which prevents your camera from connecting. List video devices:

sudo fuser /dev/video*
/dev/video0:          1418m

Dig a bit more:

ps aux | grep 1418
root        1418  0.0  0.8 304784 65344 ?        Sl   20:36   0:02 ...

Then kill the process if you wish:

sudo kill 1418

Install OctoPrint

  1. Install OctoPrint manually and start the server: 
    cd ~
python3 -m venv OctoPrint
. OctoPrint/bin/activate
pip install -U pip
pip install OctoPrint
octoprint serve
  2. To start OctoPrint on boot: crontab -e and add @reboot /path/to/OctoPrint/run.sh. Then create the run.sh file as follows: 
    #!/bin/sh
cd /path/to/OctoPrint
. ./bin/activate
/usr/bin/nohup octoprint serve --port 5001 &

    I use port 5001 above (different from the OctoPrint default of 5000) because the Flask REST server that is part of the present raspberry-py package uses port 5000. In the above, be sure to replace /path/to/ as appropriate.

  3. The following script, which you can save as webcam.sh, will toggle the mjpeg-streamer on and off: 
    #!/bin/sh
cd /path/to/mjpg-streamer/mjpg-streamer-experimental
if test -f streamer.pid; then
    kill `cat streamer.pid`
    rm streamer.pid
else
    nohup ./mjpg_streamer -i "input_uvc.so -fps 30 -r 1280x720 -q 100" -o "./output_http.so -p 8081 -w ./www" &
    echo "$!" > streamer.pid
fi

    In the above, be sure to replace /path/to/ as appropriate. I use port 8081 above because the Apache server used as part of the present raspberry-py package uses port 8080. Once the stream begins, you should be able to use the following values within OctoPrint’s webcam setup:

    • Stream URL: http://XXXX:8081/?action=stream
    • Snapshot URL: http://XXXX:8081/?action=snapshot

    In the above, XXXX is the IP address of the Pi system. For greater convenience, add the CMD exec plugin to OctoPrint and use the full path to the shell script as the command. This will allow you to toggle the webcam from the OctoPrint web interface.

References