skypi
Posts: 111
Joined: Sat Aug 09, 2014 11:48 pm

octoprint and old atmega based 3d printers?

Fri Feb 08, 2019 6:11 pm

OK I did a rant a while back, and I reckon after rebuild after rebuild I think I was right all along it is octoprint that is adding to the problem.

In a certain set of conditions, ATMEGA is 250k baud rate max, whereas later boards with real USB are megabit data transfer and have faster CPU's so maybe not a problem.

basically it is a complex print with lots of retracts and travels to small detail circular mounts and small circles require a lot of data throughput to do lots of small moves/prints

1. watching the print in octoprint on firefox on a not-massively-fast machine on local net but that has many many firefox windows and tabs up browsing ebay/stackexchange/assorted web sites and youtube to watch videos.

because I think network acces can be blocking and maybe the timeouts and all the extra code to cater for timeouts may cause millisecond type delays this can interrupt the data flow to 3d print board at the rate it needs to print

BASICALLY IF YOU HAVE PRINTS THAT FAIL STRANGELY TRY JUST LOADING THE PRINT USING OCTOPRINT AND STARTING IT AND THEN SHUTTING DOWN THE OCTOPRINT BROWSER WINDOW AND DON'T WATCH IT IN BROWSER

A WATCHED POT NEVER BOILS LOL

ANYWAY SEEMS TO HAVE WORKED FOR ME!

I KNOW THERE ARE FEED PROBLEMS ON MY PRINTER AS WELL DUE TO UPGRADE TO e3d and old 3mm filament being larger than 3mm and being a bit sticky in the feed chamber and bit of damage to hobbed bolt. Ordered a replacement hobbed bolt and they sent me a blunt one that would not grip anything!

edit: now I think about it, maybe I can go all the way back to openscad and lower the detail of circles that will then further up the chain need less gcode to print a mount....

funny how making a post/comment makes a further self-answer to the question appear...

maybe it is in the codification of the problem for a post that pops up some logical possible solutions for yourself?

skypi
Posts: 111
Joined: Sat Aug 09, 2014 11:48 pm

Re: octoprint and old atmega based 3d printers?

Sun Feb 10, 2019 6:43 pm

seems this practitioner has id'd the problem

so, cutting out the marlin SD/LCD support improves the usb print, unfortunately seems velleman have woven their sd support into the code so it is not easily commented out.... i.e. not just a #define in configuration.h

http://lokspace.eu/bad-print-quality-wi ... n-is-here/

(oh yeah, and reducing openscad circle accuracy cut the gcode from 1mb to 500k just for four small mounts)

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scruss
Posts: 2479
Joined: Sat Jun 09, 2012 12:25 pm
Location: Toronto, ON
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Re: octoprint and old atmega based 3d printers?

Sun Feb 10, 2019 8:38 pm

Are you using a Raspberry Pi Zero? I've seen people have glitches with those, especially if you're streaming the webcam at the same time. Something to do with the lack of a dedicated USB controller. If your ATMega-based print controller has an unmodified Arduino at its core, remember they will reset if they lose a serial connection. This is something that OctoPrint does not like at all.

GCode streaming isn't very onerous. The print job that's oozing out of my Ender 3 (ATMega128) right now is estimated to take 41 minutes for a 2.4 MB GCode file. That averages out at around 1000 bytes / second, or a little over 9600 baud. The physical travel time of your printer means there's lots of waiting for OctoPrint to do.

I've had flawless results with ATMega printers and OctoPrint.There might be something else wrong with your workflow.
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