Raspi and Duet 2



  • Is there a way to utilize SPI for a faster connection to Duet 2 wifi boards from a Raspberry Pi, similar to what is being done by the ribbon cable that comes with the Duet 3 for Raspi? Im noticing that my Duet 2 wifi machines, while running pressure advance, hiccup ever so slightly when printing from octopi over USB vs uploading the file directly to the D2 SD card.



  • There is an overall plan to make the Duet 2 series able to do the same as the Duet 3 and work alongside a Pi over SPI. Afaik it should be possible to retrofit an existing Duet 2 once this happens, but it will require removing the Wifi or Ethernet module and connecting to the SPI bus, which might not be for everyone (and the exact details aren't known so it might mot be as straight forward as that either).

    However I'm not sure such a Duet 2 will work faster with respect to Octoprint that would likely still need to be run through USB or shorehorned into working through DSF which is not currently a priority by the developers or community afaik.



  • @bearer Soldering isn't a problem here as we have a background in electronics development. Our only gripe with the Wifi 2 is the painfully slow upload speeds. Most files we send to our printers are 12-hour+ prints 40mb or larger. And that is a 1min+ upload, no big deal for a single, but when you've got 24.. and you're back and forth to the printers getting them started.. The time adds up. Were getting 10x the speed with raspi 3s and 4s at less than 8 seconds on average. FYI my print room has a dedicated AP using its own gateway.



  • If you're sending the same file, or at the same time, could you not send it in parallell to all the boards?

    I'm sure some of the fairly clever people on here might come up with ways to improve the workflow if you elaborate a little on the use case.

    Anyways, the point I was making with respect to speed was that a Duet 2 with a SPI interface to a Raspberry Pi will most likely still have the same bottleneck between the Duet and Octoprint even if you can upload g-code to the Pi faster than to the Duet - unless Octoprint is made to run over the same SPI bus (unlikely to be a priority afaik)

    dc42 has previously said that a Duet2Ethernet most likely will not need soldering to make it work with a Raspberry Pi once the firmware support is in place, just unplug the Ethernet module and run a custom cable to the Pi GPIO port and you have an uncle named Bob. In which case the same Ethernet header is present under the Wifi modue when desoldered. (But things could theoretically change, so until we see what they do, ymmw)


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