Cerealbot/Software

Webcam

To list available formats:

v4l2-ctl --list-formats

or

v4l2-ctl -d /dev/video0 --list-formats-ext

Octoprint

To use an http stream with octoprint, the URL has to be formatted correctly.

At first glance, I tried: cerealbox.256.makerslocal.org:8081, which didn't work.

Turns out Octoprint blindly appends a GET variable to the URL, which turns the above into: cerealbox.256.makerslocal.org:8081?2354jk345 which isn't a valid URL anymore.

So, you have to set up the webcam URL like: http://cerealbox.256.makerslocal.org:8081/

Here the trailing slash lands the GET variable. It took Hunter Fuller to figure all that out.

mjpg-streamer

mjpg-streamer is by far the best solution for webcam streaming from the RPi. A recent update brought immense relief for CPU overhead.

Base command to run:

mjpg_streamer -b -i "./input_uvc.so -d /dev/video0 -n -f 5 -r 1280x720" -o "./output_http.so -p 8080 -w ./www"

Previously I've used the -y flag for compatibility, which totally crushed the little CPU, but the most recent build of mjpg-streamer appears to work quite well with my Logitech webcam using the default MJPG codec.

Slic3r Config

I'm still working on a Slic3r config, its on github.

Octoprint Server - RPi

Authbind

tl;dr: haproxy bad, authbind good.

In '/etc/default/octoprint' Set port to 80 and uncommand the extra arguments.

In '/etc/init.d/octoprint' Add 'AUTHBIND=/usr/bin/authbind' to the variable declaration section and then find the invocation of $DAEMON and add $AUTHBIND directly in front of it (with a space). When you restart the service, it should come up on port 80.

Archlinux

To run octoprint from port 80 as user 'octoprint', I adjusted the systemd unit file to launch with authbind.

[Unit]
Description=Octoprint 3d Printing Web Server
After=network.target

[Service]
User=octoprint
Group=octoprint
Type=simple
ExecStart=/usr/bin/authbind --deep /usr/bin/octoprint --port 80
Restart=on-failure

[Install]
WantedBy=multi-user.target

Right now I'm streaming the webcam from v4l-mjpg-streamer, total pain, will look for something better.

Protips

BYOBU

• F1 allows you to set "log into byobu" to save some time while logging in.

• 'C-a a' will send C-a to screen, so that you can use screen within byobu to debug the printer's serial connection.