Octoprint is a server that runs on a RPi.  One can install Raspian (RPi OS) and then use it to install OctoPrint.  This has the advantage that you have a RPi desktop environment for various fiddling later on.  However, then you suck up a lot of space and processor cycles, and there is more to go wrong.  The simplest installation has a simple CLI and the OctoPrint system only.  That’s the approach I used.

Useful Links

https://manual.prusa3d.com/Guide/1.+Printer+disassembly/586?lang=en

Preparing the uSD card

• My initial starting point: http://diy3dtech.com/octopi-and-octoprint-project/

• A word of warning here… Don’t ever insert/remove the card when the RPi has power or you will be sorry.
• Plug an ethernet cable into the RPi
• Put the SD card in RPi and power it up.

Configuring WiFi

You should now be able to login remotely to the RPi.  It seems to take a few minutes before the system is setup and registers itself with the DNS as octopi.local.  If you get impatient then you’ll have to root around in your router to find out its IP address.

• Suggest you use putty to ssh to octopi.local   credentials: pi/raspberry
  
• when logged in, type the following commands:

cd /boot
ls
sudo nano octopi-wpa-supplicant.txt

•  Use the arrow keys to scroll down to the line that says “## WPA/WPA2 secured”
• Using your considerable experience using screen editors change the following lines to look like this:

# WPA/WPA2 securednetwork={
ssid=”put your SSID here”
psk=”put your WiFi password here”
}

• Control-O, followed by ‘<cr>’  to write out the changed file
• Control-X will exit nano 
  

  Editing the file using the RaspberryPi nano screen editor

N.B.

Configuring OctoPi 

• Go to http://octopi.local.  You should see the “setup wizard”.
• Follow the setup instructions
• I disabled access control, but I changed my password to something short ‘p’ 🙂
• I enabled anonymous usage reporting
• Enable connectivity check
• Enable plugin blacklist processing
• Skipped the Cura profile
• Set up the printer profile:  General and Build Volume

Here’s what I typed in in the order it was demanded

Prusa i3 (original)MK2.5rectangularlower leftyes250mm210mm200mmX: 0/250, Y: -4/210, Z: 0/200 6000 mm/min 6000 mm/min 200 mm/min 300 mm/min 0.4 mm1

• Finish and Reload interface
• Check in top left of Web Interface to see if any Updates are offered, and presumably accept them.
  

Setting up OctoLapse

https://github.com/FormerLurker/Octolapse/wiki/Installation
https://www.youtube.com/watch?v=CjOIxKxb3h8  GREAT VIDEO!

• This may not be required if video streamer working already
  sudo git clone https://github.com/FFmpeg/FFmpeg.git
• Open and sign into Octoprint.
• Click the settings icon (wrench icon)at the top of the page.
• Select the ‘Plugin Manager’ link on the left side of the settings popup.
• Click on the ‘Get More…’ button towards the bottom of the Plugin Manager page.
• Type ‘octolaps’ (without the ‘e) into the search box and click ‘Intall’ when the Octolapse plugin appears.
  

  

• After installation is complete, follow the prompts to restart Octoprint.
• After OctoPrint reloads clear your browser’s cache (instructions vary by browser, but typically pressing ctrl+f5 will work).
• OctoPrint Settings (spanner)/Octolapse/Main/Edit Main Settings  scroll down to “Snapshot time” and untick it.    Save, and get back to the OctoLapse Main Menu
• Select your printer from the printer dialog

Now the tedious bit

When Octolapse sees one of these commands go by it triggers the camera, so we have to tell OctoPrint to generate this sequence at the right time.  We do this in the SLic3r Printer Settings.  Note that we need to be in Expert mode to be able to change the Custom G-Codes.  We add G4P1 (no space) on the end of the “After layer change G-code”.

Now we have to set up the stabilization parameters in Octolapse.  There are a bunch of clever options, but “Extruder at Back Left” is simple and brings the model forward for the snapshot.

Next we setup the Snapshot thingummy to tell it to expect a signal using GCode.

Now we have to tell it the output speed of the video. I’m not sure if there is always one snapshot per frame in the output.  They suggest 40 fps, but 15fps seems a more sedate pace, and it can be speeded up with post processing if required.

Setting up the Camera

Still in Octolapse Settings…

The 8080 in the address is going to be the port of the camera service.   So if we type our server address with the port 8080 we will see the output of the camera.

Here’s what I see:

This is the place we focus on to get the camera set up for the run.

** Subroutine: Some more putty work **

Before doing anything else go back to the PuTTY remote shell connected to octopi.local.  Login and use cd to the /boot directory.
cd /boot
sudo nano octopi.txt

scroll down to the end of the file and make these changes.  There is a permission issue if you don’t do this before the next bit.

The most important parameter is the Snapshot Delay.   This delay allows the who rig to stop shaking around before the picture is taken.  Shorter durations may be OK.

Octolapse on the left and real-time video view on the right

You just have to fiddle with these to get them right.  Hit “Apply Now” to see how the video is affected.

JPEG to 100 is good.
Always turn autofocus OFF and adjust it in the box below

Here’s some parameters that worked for the image below:

Other Useful Plugins

Bed Visualizer

This one seems to impact other installations, so it is out of alphabetical order, and last!  These settings are required to make the window wider so that you can accommodate more tabs like this.  See settings below in gray panel.

Full width OctoPrint Window

Settings to set up above Octoprint window config