Raspberry Pi Zero, 3, accessories  

Raspberry Pi Zero, 3, accessories

Thanks to Scott's original instructions in https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/rpi-zero-octopi-working--t12432.html I have a working 'internal' OctoPi installation based on OctoPi 0.14, and a Raspberry pi zero W. I'm still running firmware b138, and have had a few oddities (a technical part that ended up with a 'blob trail' going off at an angle, and a frog with spaghetti for eyes) but have had some fair success including an almost perfect Nefertiti (just a few supports fell over early leaving her with some whiskers). Anyway, it's definitely functional.

A couple observations on the Raspberry Pi Zero W: first, I found that a OTG USB and Ethernet hub available from Adafruit fits perfectly, plugging in to the Pi's OTG port and hanging down the back of the board, and easily feeding down through the bottom of the case. Highly recommended, especially if you use a USB webcam and/or prefer to use a wired network: https://www.adafruit.com/product/2992 (similar devices likely available from other sellers, just make sure to get one with an OTG cable end, instead of the normal USB A connector.) We just need a black one to fit the color scheme.

Secondly, it's a bit slow; I'm used to the Raspberry Pi 3 running my MK2, and the OctoPi interface is noticeably slower. While the fully internal nature of the Zero is lovely (and all credit to the designers for getting the spacing and through-board header connector set up), I'd like something beefier.

I hope someone comes up with a nice reworked EINSY case that includes the space and port cutouts for a raspberry pi 3.

That brings me to PowerPanic; if folks get it working with the Zero, and if it also relies on residual power-supply capacity to shut down cleanly, all of the things I've mentioned (USB hubs, webcams, Raspberry Pi 3) are going to draw more current and make that more difficult. Something I've been using for other projects is an interesting battery-backup board for the full-sized Raspbery Pi family, called 'MoPower': http://www.allspectrum.com/mopower (it's a bit buried in the page, but there are a couple of links to where you can purchase the boards, either as a kit or assembled.)

The MoPower acts as a UPS for a Raspberry Pi, and it can fairly easily be configured to immediately start a clean shutdown when external power is removed, using just a 9V NiMH battery for power storage, which doesn't run it for long, but more than enough for a clean shutdown.

Unfortunately, it's not going to work directly, it needs a modification (minor, removing a TVS diode) to run off of the 24VDC, and more importantly also uses the RPi TX/RX lines for communication, so that's not going to work with the EISNY header at all; there are apparently some RPi UART HATs out there, but this is starting to sound very complicated... anyway, I wanted to mention that it existed, so folks can think about integrating it.

Thanks for all the hard work, it's been a fun Christmas; have a happy new year!