Pi Zero W + USB wifi

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1

I have been testing the use of Pi zero W using a USB wifi adaptor and the CSI camera.
As it has been reported that this should solve the problem of excessive CPU usage by disabling the onboard wfi+bluetooth.

Setup:
Pi zero W
Pi camera connected via CSI
USB hub
USB wifi adaptor RTL8191SU chipset
Octopi (stretch)

With an active browser session, the webcam streaming, and a print from raspi SD card at 60mm/s I didn't see CPU usage above ~60% and usually sitting around 50%.

What are the concerns that I should be aware of that I would notice if the Pi zero was causing problems.
From what I have read people were seeing 80%+ CPU usage and freezing of the printer during a print resulting in poor prints or failed completely.

2

That won't cut it.
The pi zero is barely able to run octoprint and using a camera on with it makes it worse.

I suggest you update to at least a pi 3 (I would buy a 3+ - it got 5 GHz wifi)

You answered you own question :slight_smile:

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3

It is running well so far in my testing but they have only been 1hr test prints at 60mm/s. It shows about 30-35% CPU load without a camera stream running, octoprint task being the majority of that at around 20-25%. When streaming and viewing the stream, haproxy task adds 18-20%. The remainder tasks make up the difference. So I am usually showing peaks of like 55-60% total CPU usage printing and viewing the stream. Ill investigate further and try more situations i.e: loading a file while printing and viewing stream. So far no compromise in print quality from my baseline of a pi3b+.

4

Official stance: the 0w is not recommended, regardless. Single core CPU, slow AF. It just is a bad experience compared to a 3b.

If it works for you, be happy, don't come complaining if it doesn't :wink:

5

The Zero is good for off-loading a webcam to a dedicated server. It's perfect for that, actually.

It also works (okay) as a downstream rfc2217 receiver as streamed from a four-core Raspberry Pi 3B. And yet, a 3A+ downstream works even better in that role and has the correct connector size for the cable.

Gcode streaming directly from the Zero will end up costing you more failed parts over time. You've been lucky up to this point; the Zero has half the RAM and a single core. And jeez, you've got a webcam on that too. You'll eventually find some print job that will eat your face with plenty of short line segments.