Powering 2 pi 3B+ sbc's from Duet 3



  • I'm using a second pi 3B+ to operate a monitoring camera. I looked on the duet 3 hardware overview page and did not find data that would lead me to believe one way or the other weather it would be ok to power a second pi from the Duet 3. If it's even a little iffy I'll wire a buck converter.



  • @luckyflyer

    I believe the Duet 3 can only supply up to 3A on the 5V supply. Running 2 Pi would probably need more than that.



  • @luckyflyer said in Powering 2 pi 3B+ sbc's from Duet 3:

    If it's even a little iffy I'll wire a buck converter.

    It's a LOT iffy. 🙂 The total power budget for the onboard Vin->5v converter is only 4A. You'd be better off with a separate 5V PSU that can provide at least 6A and wire direct from the PSU to the 3 devices. If you have USB stuff hanging off the RPis, consider even more power output.



  • The Pi HAT spec say only 2A external power is needed, not sure if they've updated it to reflect newer boards though, but still say 2A. (Forgot to add the above are both correct, the part is spec'ed for 4A but Duet said to only use 3A).

    Also, why not try to move the cam to the first Pi?



  • I wasn't aware that I could put the cam on the duet pi . Can motion eyes coexist with with the duet software, or is there some other cam program to use?



  • Not familiar with the software in question, but DuetPi is just a raspbian image; and the only potential conflict would be the use of port 80 for webserver - could probably be configured around or apply IP aliasing.



  • @luckyflyer Not really. MotionEyes is an operating system itself so it doesn't play well with others. There are many camera streamers out there. The ones that come to mind are mpeg-streamer and ustreamer. The DuetPi image is based on Raspbian so pretty much any streamer software that will run on a stock Pi will work.

    @bearer Exactly what time is it where you are? Aren't you GMT + a few timezones? 🙂



  • @gtj0 I'm usually GMT+1 (or +2 for DST), but as you say + a few time zones for, uhm , reasons.



  • And the pi 3B+ has enough headroom to not bottleneck and cause problems for duet?



  • Afaik others are running cameras with OpenCV on their Pis.



  • @bearer said in Powering 2 pi 3B+ sbc's from Duet 3:

    Afaik others are running cameras with OpenCV on their Pis.

    I run timelapse during prints, with both USB and Pi cameras on the Pi that is running the Duet.

    I also do OpenCV machine vision to align multiple tools on toolchangers. That's somewhat easier on the movement system... but monitoring shows TONS of free CPU and memory on a Pi4B. I don't believe you'd have any problems; I don't believe two Pis are necessary (or desirable).

    And, as others have said: No way, no how, to power both from the Duet. I get power notifications in the log with one Pi4B, no cameras.


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