Cerealbot/rpi
I'm using an RPi 2 model B for this project. Here are my notes.
Contents
[hide]OS
Install
I'm just using Rasbian from the foundation's download page. I find Debian derivatives to be comfortable for projects such as this. You're welcome to use whatever distro you like.
I strongly recommend you follow some official guide for installing the OS if you're at all uncertain. The notes here are sparse and meant to make it faster for me to recover from a broken system.
Get the archive, extract the file. Should be along the lines of '2015-05-05-rasbian-wheezy.img'.
Flash it to the SD card: 'sudo dd if=2015...img of=/dev/sdX bs=4M'.
Configure things with the raspi tool that loads on first boot, then install your favorite packages. Mine are:
htop vim emacs byobu tmux build-essential bash-completion haproxy authbind
Set the time/zone
http://aryo.lecture.ub.ac.id/configure-timezone-settings-on-raspberry-pi-raspbian-wheezy/
By default, Rasbian has an ntp daemon running, but you may still need to select a timezone. Use tzselect to set the timezone, then echo the returned line into .profile.
for me, this means:
echo "TZ='America/Chicago'; export TZ" >> ~/.profile
Setup SSH
I really recommend setting up SSH keys. There are many good guides for this elsewhere.
Setup Git
There's really no need to do this, but I like having git handle passwords for me.
https://help.github.com/articles/caching-your-github-password-in-git/
git config --global credential.helper 'cache --timeout=3600'
Setup Byobu
- F1 allows you to set "log into byobu" to save some time while logging in.
- 'C-a a' will send C-a to /usr/bin/screen, so you can use screen within byobu to debug serial connections.
Recover SD Filesystem
Hypothetically, in a strictly theoretical sense, with no basis whatsoever to the real world and real people:
Say someone at your hackerspace is horsing around and trips the breaker that your Pi is powered from. Well if you're lucky, then you just walk over and reboot the sucker. Sometimes that doesn't work though, and the computer's little SD card has become corrupt. Rather than break out the backup that you totally have, let's try a quick recovery first.
First, remove the SD card and insert it into your computer. Make sure it is unmounted.
Test recovery:
sudo dd if=/dev/sdX2 of=pi_bkup.img cp pi_bkup.img pi_bkup_recv.img sudo e2fsck -fy pi_bkup_recv.img
You may have to run that last command twice, idk why. If the program successfully recovers the test image, you have two options:
- Flash this cured image file back to the partition it came from
- Try to directly recover the SD card, since you know it has a chance of working.
The second option is faster:
sudo e2fsck -ft /dev/sdX2
Good luck!
Octoprint
Install
There are good guides elsewhere for installing Octoprint. I really don't see a need for repeating the instructions.
- Install Octoprint
- Have it start on boot
- Configure your account
- Generate an API key
Authbind to Port 80
If your network supports it, go ahead and use HAProxy. Ours didn't work initially, so I gave up and instead used Authbind.
https://mutelight.org/authbind
sudo apt-get install authbind sudo touch /etc/authbind/byport/80 sudo chown pi /etc/authbind/byport/80 sudo chmod 500 /etc/authbind/byport/80
Adjust a few lines in /etc/default/octoprint to match:
... PORT=80 ... DAEMON_ARGS="--port=$PORT" ...
In /etc/init.d/octoprint you need to add a line for authbind in the variable declaration area:
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin DESC="Octoprint Daemon" NAME="Octoprint" DAEMON=/usr/local/bin/octoprint AUTHBIND=/usr/bin/authbind ...
In the same file, you then need to find the line which starts octoprint and insert authbind:
start-stop-daemon --start --background --quiet --pidfile $PIDFILE --make-pidfile \
--exec $DAEMON --chuid $OCTOPRINT_USER --user $OCTOPRINT_USER --umask $UMASK -- $DAEMON_ARGS
To:
start-stop-daemon --start --background --quiet --pidfile $PIDFILE --make-pidfile \
--exec $AUTHBIND $DAEMON --chuid $OCTOPRINT_USER --user $OCTOPRINT_USER --umask $UMASK -- $DAEMON_ARGS
MJPG-Streamer
First, you may want to collect some information on your webcam:
To list available formats:
v4l2-ctl --list-formats
or
v4l2-ctl -d /dev/videoX --list-formats-ext | less
Install
There are general instructions for installing mjpg-streamer on octoprint's wiki. I've detailed some changes to incorporate a different version and setup a daemon.
mjpg-streamer is by far my favorite solution for webcam streaming from the RPi. A recent update brought immense relief for CPU overhead.
Install some dependancies:
sudo apt-get install libjpeg62-dev cmake subversion imagemagick libav-tools <pre> Git the project: <pre> git clone https://github.com/jacksonliam/mjpg-streamer.git cd mjpg-streamer/mjpg-streamer-experimental/ make clean make all
The base command to run mjpg-streamer. Don't worry about this, its handled by an init.d script.
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-experimental appears to work quite well with my Logitech webcam using the default MJPG codec.
Setup Init Script
Go to foosel's mjpg init page and copy-pasta the two files into /etc/init.d/mjpg-streamer and /etc/default/mjpg-streamer respectively.
Don't forget to edit /etc/default/mjpg-streamer to your liking, and make /etc/init.d/mjpg-streamer executable!
sudo chmod +x /etc/init.d/mjpg-streamer sudo update-rc.d mjpg-streamer defaults
Octoprint Protip
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.
