Difference between revisions of "Cerealbot/rpi"

Revision as of 15:54, 10 August 2015

I'm using an RPi 2 model B for this project. Here are my notes.

Pi <-> RPi <-> Raspberry Pi

Cerealbot Code

API

Curl is great for testing around with both Octoprint and RedQueen's api, but I've switched the shell scripts to use resty for ease of maintenance.

Curl Examples
To RedQueen:
curl --data "{\"message\":\"${MSG}\", \"channel\":\"##rqtest\", \"isaction\":false, \"key\":\"${APIKEY}\"}" https://crump.space/rq/relay -H "Content-Type:application/json"
To Octoprint:
curl -H "X-Api-Key:$OCTO_API_KEY" http://bns-daedalus.256.makerslocal.org/api/printer -o /tmp/printr_status.json

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

Reference thread

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

This is the current go-to tool for webcam streaming with octoprint. If you have a webcam set up, then you can totes ignore this section. It's also worth browsing around to see if you find a process you like better than mine.

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

Git the project:

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

If you have troubles, make sure to sudo update-rc.d mjpg-streamer remove and then reboot each time while working on it manually.

I've modified the init scripts while facerolling to try and get this junk working.

/etc/init.d/mjpg-streamer:

#!/bin/sh

### BEGIN INIT INFO
# Provides:          mjpg-streamer
# Required-Start:    $local_fs networking
# Required-Stop:
# Should-Start:
# Should-Stop:
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: mjpg-streamer daemon
# Description:       Starts the mjpg-streamer daemon with the user specified in
#                    /etc/default/mjpg-streamer.
### END INIT INFO
 
# Author: Sami Olmari
 
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DESC="mjpg-streamer Daemon"
NAME="mjpg-streamer"
DAEMON=mjpg-streamer
PIDFILE=/var/run/$NAME.pid
PKGNAME=mjpg-streamer
SCRIPTNAME=/etc/init.d/$PKGNAME
 
# Read configuration variable file if it is present
[ -r /etc/default/$PKGNAME ] && . /etc/default/$PKGNAME
 
# Exit if the mjpg-streamer is not installed
[ -x "$DAEMON_HOME/$DAEMON" ] || exit 0
 
# Load the VERBOSE setting and other rcS variables
[ -f /etc/default/rcS ] && . /etc/default/rcS
 
# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions
 
if [ -z "$RUN_AT_STARTUP" -o "$RUN_AT_STARTUP" != "YES" ]
then
   log_warning_msg "Not starting $PKGNAME, edit /etc/default/$PKGNAME to start it."
   exit 0
fi
 
if [ -z "$MJPG_STREAMER_USER" ]
then
    log_warning_msg "Not starting $PKGNAME, MJPG_STREAMER_USER not set in /etc/default/$PKGNAME."
    exit 0
fi
 
#
# Function to verify if a pid is alive
#
is_alive()
{
   pid=`cat $1` > /dev/null 2>&1
   kill -0 $pid > /dev/null 2>&1
   return $?
}
 
#
# Function that starts the daemon/service
#
do_start()
{
   # Return
   #   0 if daemon has been started
   #   1 if daemon was already running
   #   2 if daemon could not be started
 
   is_alive $PIDFILE
   RETVAL="$?"
 
   if [ $RETVAL != 0 ]; then
       start-stop-daemon --start --pidfile $PIDFILE --make-pidfile --chuid $MJPG_STREAMER_USER --user $MJPG_STREAMER_USER --umask $UMASK \
--exec $DAEMON_HOME/$DAEMON
       RETVAL="$?"
	echo "\nRetval: $RETVAL"
   fi
}
 
#
# Function that stops the daemon/service
#
do_stop()
{
   # Return
   #   0 if daemon has been stopped
   #   1 if daemon was already stopped
   #   2 if daemon could not be stopped
   #   other if a failure occurred
 
   start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --user $MJPG_STREAMER_USER --pidfile $PIDFILE
   RETVAL="$?"
   [ "$RETVAL" = "2" ] && return 2
 
   rm -f $PIDFILE
 
   [ "$RETVAL" = "0"  ] && return 0 || return 1
}
 
case "$1" in
  start)
   [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
   do_start
   case "$?" in
      0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
      2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
   esac
   ;;
  stop)
   [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
   do_stop
   case "$?" in
      0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
      2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
   esac
   ;;
  restart)
   log_daemon_msg "Restarting $DESC" "$NAME"
   do_stop
   case "$?" in
     0|1)
      do_start
      case "$?" in
         0) log_end_msg 0 ;;
         1) log_end_msg 1 ;; # Old process is still running
         *) log_end_msg 1 ;; # Failed to start
      esac
      ;;
     *)
        # Failed to stop
      log_end_msg 1
      ;;
   esac
   ;;
  *)
   echo "Usage: $SCRIPTNAME {start|stop|restart}" >&2
   exit 3
   ;;
esac
:

/etc/default/mjpg-streamer:

# Configuration for /etc/init.d/mjpg-streamer
 
# The init.d script will only run if this variable non-empty.
MJPG_STREAMER_USER="pi"
 
# Where mjpg-streamer is installed, this is important!
DAEMON_HOME=/home/pi/mjpg-streamer/mjpg-streamer-experimental
DAEMON=start.sh
 
# What arguments to pass to mjpg-streamer, here is few examples; You can change them by commenting one and
# uncommenting another:
 
export LD_LIBRARY_PATH=$DAEMON_HOME

#DAEMON_ARGS='-i "$DAEMON_HOME/input_uvc.so -r SXGA -f 15" -o "$DAEMON_HOME/output_http.so"'   # UVC-mode
#DAEMON_ARGS='-i "$DAEMON_HOME/input_uvc.so -y" -o "$DAEMON_HOME/output_http.so"'              # YUV-mode

# Umask of files mjpg-streamer generates, Change this to 000 if running mjpg-streamer as its own, separate user
UMASK=022
 
# Should we run at startup?
RUN_AT_STARTUP="YES"

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.

Node JS

Installing

http://elinux.org/Node.js_on_RPi - EEwiki page on downloading / building from source.

https://nodejs.org/dist/latest/ - Latest source release.

Building:

wget https://nodejs.org/dist/latest/node-v0.12.7.tar.gz
tar xzf node*.tar.gz
cd node-v0.12.7/
./configure
make -j 3
sudo make install
<pre>

== UV4L ==

uv4l is a promising tool to replace mjpg-streamer with faster performance on the RPi 2. Right now it just crashes my pi though.

[http://raspberrypi.stackexchange.com/questions/7446/how-can-i-stream-h-264-video-from-the-raspberry-pi-camera-module-via-a-web-serve http://raspberrypi.stackexchange.com/questions/7446/how-can-i-stream-h-264-video-from-the-raspberry-pi-camera-module-via-a-web-serve]

[http://www.linux-projects.org/modules/sections/index.php?op=viewarticle&artid=14 http://www.linux-projects.org/modules/sections/index.php?op=viewarticle&artid=14]