Duet3 - powering a RaspPi4 without the full SBC interface?



  • I managed to kill my duet wifi this morning, and I don't think replacing it with another Duet Wifi is the best choice.

    However, the printer isn't in a location where wired ethernet is available, so I was thinking of using a Raspberry Pi as a wireless bridge to the duet3. (I don't want to lose PanelDue functionality, so I'm not really interested in using the raspberry pi with all the DSF stuff.)

    Is it possible to power a raspberry pi via the duet3 without the full DSF/server stuff running on the Pi? What pins would have to be connected?

    Also, if anyone else has converted from a duet wifi to a duet 3, I'd appreciate any suggestions on lessening the pain of converting...



  • 5V and Gnd and you are in business. But... if I understand it correctly, you do NOT need to disconnect any pins in the provided cable. Do two things:

    1. Put an SD in the D3, with a full /sys, /sys/www, and so forth. If the D3 sees a /sys/config.g, it will never even try to talk to the Pi.
    2. Don't install DuetSoftwareFramework (DSF) on the Pi. Either use your own preferred Raspbian image, or remove DSF from the Duet provided image.

    Really (1) is all that is absolutely required.

    Curious, will the Pi be WiFi to Ether and that Ether cable goes to the D3? So the Pi is configured as a mini bridge and/or router?

    And, just a pitch for the full Pi... a 45 dollar screen, and the correct "scale=nn" setting (I believe you've been in those threads), and I'm liking it much better than I ever liked my PanelDue.



  • @Danal said in Duet3 - powering a RaspPi4 without the full SBC interface?:

    Curious, will the Pi be WiFi to Ether and that Ether cable goes to the D3? So the Pi is configured as a mini bridge and/or router?

    Yes. I believe I can get a Pi to act as a transparent wifi bridge, so the Duet3 thinks it's actually wired into my network switch, but it's really plugged into the Pi (and the Pi is fowarding IP traffic over wifi.)

    I remember that wifi/ethernet bridges used to be fairly common for older "wired ethernet only" devices to be able to connect to wifi (such as older game consoles, printers, etc), but they're probably more expensive than a raspberry pi is, and if I can power the Pi from the duet3 board, that also saves the expense of a power adapter for the Pi... (In addition, those bridges can't cannot to EAP wifi, while a Pi can - which I'd really like the option for.)

    As for using the full ribbon, I'd like to avoid that for the sake of simplicity. If I can just run two 300mm jumper wires from the duet to the Pi, I'll have much more freedom in where I can put the Pi.

    And, just a pitch for the full Pi... a 45 dollar screen, and the correct "scale=nn" setting (I believe you've been in those threads), and I'm liking it much better than I ever liked my PanelDue.

    Perhaps, but I'm already having an unexpected expense of 230 USD for the duet3, so it'd be really hard to justify (to my wife) anything more. As well, I have to be honest in saying that I haven't researched the whole duet3/DSF thing enough to full trust it. It seems that it'd be an additional point of failure.

    (While having a Pi as a network bridge is also a second point of failure, the printer is still fully usable with only the duet3 and paneldue functioning.)



  • @garyd9 said in Duet3 - powering a RaspPi4 without the full SBC interface?:

    Yes. I believe I can get a Pi to act as a transparent wifi bridge, so the Duet3 thinks it's actually wired into my network switch, but it's really plugged into the Pi (and the Pi is fowarding IP traffic over wifi.)

    There is a thread on here somewhere that goes over the details of that, I rested it with the the now passé Raspbian Stretch at least. TL;DR yes it works.



  • @garyd9 said in Duet3 - powering a RaspPi4 without the full SBC interface?:

    If I can just run two 300mm jumper wires from the duet to the Pi, I'll have much more freedom in where I can put the Pi.

    Yah, that will absolutely work just fine. And possibly even dandy.

    Wire gauge for those jumpers: With no camera, no USB, they draw about .8 amp or 1 amp peak. With lots-o-peripherals, they can draw 2.5 or 3.



  • @Danal said in Duet3 - powering a RaspPi4 without the full SBC interface?:

    Wire gauge for those jumpers: With no camera, no USB, they draw about .8 amp or 1 amp peak. With lots-o-peripherals, they can draw 2.5 or 3.

    PiCam, Ethernet, a hobby servo and Wifi... hmm..

    Assuming 3amps, my chart tells me AWG of 17. However, there's no way that the 3.5 Amp USB-C wall wart that comes with the RaspPi4 kit (canakit) is even close to 17AWG. Being you brought it up, what do you think a suitable AWG would be for 5V/3A? Distance of no more than 300mm. (I could probably do 2x stranded 24guage for GND and +5VDC - for a total for 4 wires...)



  • you might find it tricky to find crimp terminals for anything thicker than 22 AWG, i think thats what i used,. two for 5v, 2 for ground and another ground together with the spi connection so i could plug and unplug them independently.


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