Prusa MK3 – Pi Zero W (NOT)

With my Prusa MK3 up and running I was ready to install the Pi-Zero W I had prepared. I didn’t want the Zero installed until I was sure the printer was working and it was nice to just follow their instructions, which are great, step-by-step.

Warning Will Robertson…

I should have stopped when the image for the PiZeroW was 404 on the Prusa site, and I almost did.  Then I read in the comments that it was being worked on and was expected in a few days.  I had already setup manually in preparation so I was aware it had been 404 for a couple of weeks that I was aware of it.  Based on the warnings about the Pi Zero and not having a ‘supported’ build I was a little concerned.

Tear it apart?

Ok, not such an easy upgrade. Take off the cover, remove the board, and push the extra long pins I had to order special for this task through, then reassemble.

Not too bad but not something I wanted to do again making it very concerning that the Zero was so inaccessible.

No Communication…

I had already configured the Zero but in place it wasn’t communicating.  I found the setting to enable the rPi port and then found a posting on how to configure the communications port on the Zero as well as configure OctoPrint.  Whew, that did it!

Working, or maybe not?

Everything seemed to be working but my first six hour print job just stopped mid-job, nozzle frozen in the print. I thought the MK3 was supposed to be smart…

In working with small prints to learn about filament changing I noticed stutters and broken print.  I wasn’t sure what to think of it but printing from SD card I had seen nothing but perfect prints so I suspected the Zero.  There as also overall strange behavior where despite only have one filament change command in the code the printer stopped several times to change filaments.

It was when a job just quit while I was watching and I heard the fans startup like they do after a reset.  I’ve observed the same behavior when OctoPrint first connect with the USB.  This made me suspect the Zero reset it’s communication link or something.  The Zero was connected to the communication pin no matter what I did. When trouble shooting something sporadic it is best to remove what you can to eliminate as much as possible from the formula.

Rip it out!

OK, cover off, board out, rPiZero removed, everything put back together and in place.

I liked the idea of a built in WiFi solution for operating the printer and OctoPrint is what I use.  However, the PiZero is a single core unit and seems to be more of an issue than a solution.

Problems I see with the embedded PiZero

  • Not really supported.  Looking at the supported OctoPrint image there was question on the PiZero, especially related to streaming video.
  • No Video.  Since there is no access to the unit it would be difficult to run a video cable even if video was supported.
  • Incorrect shutdown.  Every time the MK3 is powered off the Pi is powered off regardless of what it might be doing at the time.  This is concerning to me especially since files have failed to load after a crash so I’ve witnessed file corruptions.
  • To access the Zero you must partially disassemble the printer.  There is no way to remove it when troubleshooting. Also, it is always on even if you disable the port via settings.  You could ssh into it and shut it down but a complete removal eliminates all potential conflicts.


I am loving my MK3 and have absolutely no idea of what you could do to upgrade it.  I strongly discourage installing a Pi Zero W.

You get a much nicer printer when you pay for an Original Prusa. It is the printer I wanted and the only ‘pre-order’ I’ve ever placed.   I picked up an ANet A8 while I was waiting to gain some experience. In that, the A8 worked out well, I learned a lot about printing and what can go wrong.  If you buy a cheap printer expect to spend your time printing upgrades for your printer.

I’ve found my ANet to be a very needy device, demanding my attention on a regular basis just to keep it running smoothly.  It is a great ‘hobby’ printer for a DIY person.  It requires someone who likes tinkering and isn’t concerned about being productive because of all the time spent doing upgrades.  For me it has worked out well while I have waited and makes me really appreciate what Joseph Prusa is doing.

I am look forward to just printing with my new printer instead of upgrading.  I’ve already started working through filament changing and can see that I will have a lot to talk about in designing for multiple materials.  I am really looking forward to the Multi-Material kit which will automate the filament changes.  Hopefully in May based on the last announcement.

Author: Marc

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