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    Idea: "barebones" Duet3D mainboard, maybe as Pi hat

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    • CNCModellerundefined
      CNCModeller
      last edited by

      @sonderzug

      I've been thinking this for a while. Especially relevant now I'm looking into conversion of my CNC mill and lathe. The plan was to use can for everything if possible.

      Devs, is there a generic board that we could tie a can module to, or would that require a specific branch of the duet code? Or could we just run the code on something with the right processor and can already integrated?

      Any thoughts would be great.

      Many thanks
      Barry M

      Polar Duet3 Mini + 1HCL
      https://youtube.com/playlist?list=PLWjZVEdMv1BY82izahK45qKh-hp3NFkix
      Wanhao D4S: Duet2
      https://forum.duet3d.com/post/296755
      K40 Laser, Duet2
      https://forum.duet3d.com/post/312082
      Wanhao D5S
      https://www.youtube.com/CNCModellerUK

      jumpedwithbothfeetundefined 1 Reply Last reply Reply Quote 0
      • zaptaundefined
        zapta @sonderzug
        last edited by zapta

        @sonderzug said in Idea: "barebones" Duet3D mainboard, maybe as Pi hat:

        So wouldn't it be feasible to have a "hat" for the Pi

        Bigtreetech took a different approach, fitting the PI on the controller, but I see you point about reducing size by delegating I/O to CAN bus slaves. BTW, they also have their own version of the compute module.

        68d194cc-a8b3-4734-84ab-48e9e10a0574-image.png

        o_lampeundefined 1 Reply Last reply Reply Quote 0
        • jumpedwithbothfeetundefined
          jumpedwithbothfeet @CNCModeller
          last edited by

          @cncmodeller like this?

          https://www.sg-electronic-systems.com/can-bus-fd-shield-for-raspberry-pi/

          It would be a game changer just running expansion boards off something like this.

          6HC Voron Trident based, 6XD CNC, Mini 5 polar printer

          o_lampeundefined 1 Reply Last reply Reply Quote 0
          • o_lampeundefined
            o_lampe @zapta
            last edited by

            @zapta Do these Pi-compute modules have a camera connector?
            I don't use SBC for now, but I think an integrated camera would be on my wishlist then.

            1 Reply Last reply Reply Quote 0
            • o_lampeundefined
              o_lampe @jumpedwithbothfeet
              last edited by

              @jumpedwithbothfeet I wonder if a PI with CAN-FD equals an RTOS microcontroller board?

              jumpedwithbothfeetundefined 1 Reply Last reply Reply Quote 0
              • jumpedwithbothfeetundefined
                jumpedwithbothfeet @o_lampe
                last edited by

                @o_lampe that is electrickery beyond my knowledge!, I don't know how many of the functions are unloaded to the Pi from the mainboard in SBC mode, does the mainboard just control the steppers and provide sensor/io/power to the connected components? if that's the case why wouldn`t it work?... either way I now have many questions to try and find answers to ๐Ÿ™‚

                6HC Voron Trident based, 6XD CNC, Mini 5 polar printer

                o_lampeundefined 1 Reply Last reply Reply Quote 0
                • o_lampeundefined
                  o_lampe @jumpedwithbothfeet
                  last edited by

                  @jumpedwithbothfeet AFAIK the Pi can't do AD-conversion, which we'd need for temp-reading and PID-based PWM, but if all that would happen on the toolboards....

                  jumpedwithbothfeetundefined 1 Reply Last reply Reply Quote 0
                  • jumpedwithbothfeetundefined
                    jumpedwithbothfeet @o_lampe
                    last edited by

                    @o_lampe well they have their own processors and transmit their io via canbus so....maybe?, would you be able to update/upgrade the expansion boards without a mainboard as such, in reality these are @dc42 or @chrishamm questions! maybe they can put this to bed?

                    6HC Voron Trident based, 6XD CNC, Mini 5 polar printer

                    1 Reply Last reply Reply Quote 0
                    • gloomyandyundefined
                      gloomyandy
                      last edited by

                      It might help folks to understand how the major functions are split between the SBC, RRF main board and the CAN board in a setup like this:

                      SBC:
                      Handles the web interface (wifi, networking etc.), file I/O, gcode parsing, Optionally it can handle a camera etc.

                      RRF Main board:
                      Takes a pre-parsed gcode stream, executes the gcode instructions, performs motion planning (including homing/probing moves and input shaping), handles PID control for local heaters, generates steps for local motor drivers (including pressure advance), generates CAN commands for CAN boards, generates PWM signals for local fans, handles probes, endstops and accelerometers that are attached directly.

                      CAN boards
                      Takes commands via CAN, generates steps for drivers (including pressure advance), handles PID control for local heaters, generates PWM signals for fans, handles attached probes, endstops and accelerometers.

                      o_lampeundefined 1 Reply Last reply Reply Quote 2
                      • o_lampeundefined
                        o_lampe @gloomyandy
                        last edited by o_lampe

                        @gloomyandy said in Idea: "barebones" Duet3D mainboard, maybe as Pi hat:

                        RRF Main board:
                        Takes a pre-parsed gcode stream, executes the gcode instructions, performs motion planning (including homing/probing moves and input shaping), handles PID control for local heaters, generates steps for local motor drivers (including pressure advance), generates CAN commands for CAN boards, generates PWM signals for local fans, handles probes, endstops and accelerometers that are attached directly.

                        A few of these tasks wouldn't happen on the mainboard/PI Hat , if it only has CAN connectivity. That would safe some board space and connectors and a lot of extra copper, making it cheaper and smaller.

                        Simple Fan-PWM signals could be provided by the RasPi, if they're not too time critical?

                        jumpedwithbothfeetundefined gloomyandyundefined 2 Replies Last reply Reply Quote 0
                        • jumpedwithbothfeetundefined
                          jumpedwithbothfeet @o_lampe
                          last edited by

                          @o_lampe the pwm commands would be controlled by the expansion boards via can bus I think the biggest problem would be the motion planning and issuing the can commands surely?

                          6HC Voron Trident based, 6XD CNC, Mini 5 polar printer

                          1 Reply Last reply Reply Quote 0
                          • gloomyandyundefined
                            gloomyandy @o_lampe
                            last edited by

                            @o_lampe Just to be clear, my post described how things are done in the current version of the firmware.

                            Clearly you can move things around (though I'm not sure that moving things like fan control to the rpi makes sense if motion planning remains on the RRF board as this needs to be synchronized with motion. This is particularly true with CNC or laser control).

                            If you move most of the control logic to the rPi you are effectively describing Klipper...

                            o_lampeundefined 1 Reply Last reply Reply Quote 0
                            • o_lampeundefined
                              o_lampe @gloomyandy
                              last edited by

                              @gloomyandy
                              I understood. That's why I only mentioned Fan control. Part-cooling fan, Spindle and Laser control could be done by the toolboards.
                              I don't want to push RRF towards Klipper, but if it safes us money, I'm in. (I never tried Klipper, so there might be some drawbacks with their setting, too)

                              1 Reply Last reply Reply Quote 0
                              • jumpedwithbothfeetundefined
                                jumpedwithbothfeet
                                last edited by

                                I for one, wouldn't want to go the klipper route either, and to get this thread back on its original track I think a stripped down Duet board either with or without an SBC would be a great idea, especially as the maestro/duet 2 is realistically no longer available or a viable choice - just my opinion mind ๐Ÿ™‚

                                6HC Voron Trident based, 6XD CNC, Mini 5 polar printer

                                jay_s_ukundefined 2 Replies Last reply Reply Quote 0
                                • jay_s_ukundefined
                                  jay_s_uk @jumpedwithbothfeet
                                  last edited by

                                  @jumpedwithbothfeet what's wrong with the duet 3 mini?

                                  Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is

                                  jumpedwithbothfeetundefined 1 Reply Last reply Reply Quote 0
                                  • jay_s_ukundefined
                                    jay_s_uk @jumpedwithbothfeet
                                    last edited by

                                    @jumpedwithbothfeet you could always get an SKR3. That's just as powerful as a duet 3 6HC but with a smaller footprint

                                    Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is

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                                    • jumpedwithbothfeetundefined
                                      jumpedwithbothfeet @jay_s_uk
                                      last edited by jumpedwithbothfeet

                                      @jay_s_uk nothing wrong with the mini I would happily buy one, what I`m getting at is the range of boards is effectively limited too just two boards and their variants, and both have limiting factors in use and price, I just believe there is a case for a *stripped down universal duet board that can be tailored/built up to serve either CNC/FDM or any other project by the use of expansion boards by the user, basically a modular system.

                                      I have previously looked at other boards like the SKR but various things like the drivers have always put me off, besides that my 6HC has never let me down despite some of the stupid mistakes I've made, I`d have one in every machine I make, if I could afford it ๐Ÿ™‚

                                      *edited - added stripped down

                                      6HC Voron Trident based, 6XD CNC, Mini 5 polar printer

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                                      • sonderzugundefined
                                        sonderzug
                                        last edited by sonderzug

                                        Hi all, thank you for the lively discussion, nice to see that this idea sparks some interest.

                                        My idea was inspired for once by all of the already available expansion boards, as well as the uprising of more unconventional machines that are built, be it for the purpose of 3D printing or not. For example, as far as I can tell, people are now also working on implementing robot motion.

                                        I'd think that a robotic arm with 3D printing effector would greatly benefit, in terms of simplified wiring, by having the respective driver boards for each joint very close to the motor, daisy chained, with the effector (1LC toolboard) at the end. An interesting field since people are implementing "true" 3D printing path generation.

                                        In respect to the hardware requirements of this barebone mainboard, as has been discussed above, there has to be a ยตC on the board but I can imagine it to be a less potent one that the one found on the 6HC or even the mini 5+.

                                        @o_lampe said in Idea: "barebones" Duet3D mainboard, maybe as Pi hat:

                                        @gloomyandy said in Idea: "barebones" Duet3D mainboard, maybe as Pi hat:

                                        RRF Main board:
                                        Takes a pre-parsed gcode stream, executes the gcode instructions, performs motion planning (including homing/probing moves and input shaping), handles PID control for local heaters, generates steps for local motor drivers (including pressure advance), generates CAN commands for CAN boards, generates PWM signals for local fans, handles probes, endstops and accelerometers that are attached directly.

                                        A few of these tasks wouldn't happen on the mainboard/PI Hat , if it only has CAN connectivity. That would safe some board space and connectors and a lot of extra copper, making it cheaper and smaller.

                                        Simple Fan-PWM signals could be provided by the RasPi, if they're not too time critical?

                                        o_lampeundefined 1 Reply Last reply Reply Quote 0
                                        • o_lampeundefined
                                          o_lampe @sonderzug
                                          last edited by

                                          @sonderzug said in Idea: "barebones" Duet3D mainboard, maybe as Pi hat:

                                          here has to be a ยตC on the board but I can imagine it to be a less potent one that the one found on the 6HC or even the mini 5+.

                                          There are often smaller versions of the same MCU available, with less IO pins. As long as it has the same amount of RAM it would be ideal.
                                          The barebone would also need less copper, since there are no drivers onboard.
                                          It probably could be fed from the Raspberry and wouldn't need all the voltage converters?

                                          1 Reply Last reply Reply Quote 0
                                          • T3P3Tonyundefined
                                            T3P3Tony administrators @sonderzug
                                            last edited by

                                            @sonderzug et al

                                            We have been considering a SAME70 CAN-FD control board designed to use CAN-FD expansion for most functions for a long time now, but need to consider the total stock of these processors available to use before adding another product that uses them.

                                            If we did it Pi hat is one form factor that could be used but may not be optimal.

                                            www.duet3d.com

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