Replicape Revision A2 ready for review

Replicape_2DThere it is, the new revision of Replicape. This revision is more compatible with the new BeagleBone Black that has a built in eMMC. There are a lot of other changes as well on this revision. The most important is the moving of the stepper motor  connectors to the outside of the receptacles so removing is no longer necessary. Furthermore there is no need for a separate 12V and 5V power supply. You can now power the whole board with a single 12 to 24V PSU. Other things to mention is a major upgrade to the tracks and connectors for the heater cartridges and heated build platform, the addition of a fuse and finally a new color so that there will be no doubt which BeagleBone this belongs to : )

I’ve gotten a lot of help from Dirk Eichel on this revision, especially on the fat power tracks, the addition of a freewheeling diode¬†across the MOSFETs to suppress voltage spikes and grips to reduce noise on the ADC lines.

Although there are a lot of nice changes, there has also been a lot of work put into keeping the cost down. The total cost of the board is the the same (BOM is ~$90).

I’ll give it a couple of days to get input from the community both on bugs in the layout/schematic and feature requests. Have a look at the RevA2 tag of the repository.

41 thoughts on “Replicape Revision A2 ready for review

    • GP, I’m going to look over the BOM and board now and hopefully I can send it today! I’m using Seeedstudio for the prototypes, so the boards will be back in a couple of weeks I think. I need some time to solder at least one and get it running and if everything is OK, I can send you one! Do you want a finished board or just a PCB? Finished board including shipping is $179, PCB is $20.

  1. Pingback: Replicape – a 3D printer cape for BeagleBone | Hipstercircuits

  2. Hi Elias,

    If there is a remaining finished board for that Beaglebone Black revision, I would love to try it out.

    Let me know.


    • Mathieu, most of the boards have been promised away, but according to my list there are still two boards left. I can make one for you if you want! What are your specific plans for the board?

  3. Elias,

    That would be awesome.

    I have built a MendelMax and I wanted to upgrade it to a dual extruder system. To that optic I built a controller board based on a LPCXpresso board. This is working ok but I wanted my board to be entirely controllable within a web interface. That’s why I am really interested in the beaglebone and in your project in order to develop such interface. I can definitely give you a hand on the firmware and software side if needed.

    Let me know how you want to proceed for the board.

    Thanks a lot,


    • Mathieu, that sounds great! There is definitely room for improvement on both software and firmware and also there needs to be a good system for defining options for each printer in terms of steps pr mm, microstepping, transformations (H-belt, SCARA) etc. I’m thinking this could be done via M-codes and be set on start-up, but I am open to ideas. Dirk (the guy that helped out) has also got a MendelMax, so it’s good if you guys can talk.

      BTW, I set up a wiki today, so if you learn anything write it up there!

      I’ll contact you once I have at least one board soldered and made sure it works as it should.

  4. Pingback: Replicape Revision A2 Updates for BeagleBone Black #3dthursday « adafruit industries blog

  5. Hi, I would like to get one of the bare boards if possible. I have been working on a cape with GPS, 3 axis accelerometer and gyro and outputs to drive up to 8 RC servos from the PRU. I have a few of the first run proto boards left, if you would be interested in trading. The GPS and gyro/accelerometer are tested and operating on the first run boards. I have not done the software work for the servo outputs yet, so that is untested right now.


    • Bob, can I ask what your intended use is? I only have one board left, so I would like it put to good use:) What is the application for your board? Octapod?

      • I want to design and build a 3D printer with a larger workspace than what I am seeing on the market.

        The board I designed is sort of a building block. One of the first applications is using the GPS receiver as the reference for a time server for my home network. The MEMS gyro/accelerometers have interested me for a long time, and this seemed like a good chance to mess with them for navigation. The GPS would be used to provide a “truth” position for the experimentation. Eventually, the GPS and gyro/accelerometer could be used for an auto-pilot or auto-stabilizer for an RC model airplane or maybe a quadcopter. The servo interface is to support the autopilot possibilites.

        I want to build the larger 3D printer to try printing small RC planes.


        • Bob, it sounds like a very cool project, but it’s not something I have time for right now, so I’m not sure about a trade. I did an implentation of the AHRS algorithm for 9 DOF on the beaglebone a while back, let me know if you are interested in that and I can make it public (it is now in a private repository). If you want to buy a board, I can send you one and you can populate it yourself: )

          • Hi Elias,
            I have been thinking about my 3D printer project and my schedule right now. It will be at least this fall before I start getting serious about the printer. I am in the process of designing a 2 channel closed loop motor drive cape that I need to finish for a project that I already have the mechanical parts done. It would make the most sense for me to finish what I have started and wait until this fall to start another project. I will wait until Circuitco has your boards.
            Thanks for the offer of the AHRS code, but part of the reason that I want to do this stuff is to learn about the guts and issues of it.


          • Ok, I totally understand your reason for not wanting the code. I’m the same way : ) If you manage to get something working, it would be interesting to see it though!

  6. Do you intend to make more boards available at some stage? I’d like to try one for my Shapeoko (want to try to make it do PnP).

    • Hugo, the boards will be made by CircuitCo, the makers of BeagleBone. Hopefully they will push them out to major distributors like some of the other boards they make, but this has not been discussed yet. I’ll probably make one more iteration of the boards before they are ready for mass production (get all components on one side). If you want you can get in on that.

  7. Are you planning to sell 3d printer kits where you just add your own BBB? How much would these cost? Thanks

    • Mark, the first step is to get Replicape going and I’m interested in having it work on as many printers as possible. I’m also in the process of making a 4.3″ touch display to go with it. Further down the line there will also be a complete printer. The idea is to have it ready by Maker Fair Rome in October. You’ll find some photos of a very early prototype on this site.

  8. Hi,

    Looking at your Schematic’s I can see that you’ve got each DRV8825PWP’s configuration pins hooked up to a SPI Logic Shift. Can I ask why you didn’t do the same for the Step and DIR? So that you could shift out a step for the entire X-Y-Z-A-B in one cycle and not have to worry about manipulating GPIO pins?

    • Stephen, that is a good question. The reason I chose to have the step an dir pins separate was to let them be controlled by the prus. With a maximum speed on the spi of 16MHz, the maximum update speed for a pin would be 16000000/(8*5) = 400kHz which is more than the maximum of 250k that the drivers can handle, but it would complicate the loading of data if each update would require 5 bytes.. Still if the pins are there, why not use them?

      • I’ve been playing around with my BBB (Getting SPI and CAN working on it (Again a lot of help from you, thanks)) and from trawling the net and looking at examples etc, I see a lot of people saying that there is switching or loading delay issues with having to connect to the file system at /dev/gpio and issuing a write etc, for example and that for time critical operations, or that the way Linux time slices it’s multitasking could (not saying that it does, as it’s pure conjecture here as I haven’t tried this on a 3d printer….yet).
        So I’m wondering if you will get juddering or Spacial deformities in the 3d print because the GPIO pins are not in sync (hope I haven’t confused you).

      • I think I may have answered my own question looking through your setup. So this PRU module seems to be able to give precise pulses and timings. This seems to be something that is lacking on other devices like the Cubie Board or pcDuino.

  9. Hi Elias,
    I was looking at your replicape schematic, and perhaps I’m being a bit of a cheap-0 here, but since the Vref_x values are generally not going to be changing after setup, and CircuitCo can use those tiny resistors and capacitors, couldn’t you just get rid of the DAC088s chip and have the PCA9685 generate a PWM that gets RC filtered for the Vrefs? There seem to be plenty of PWM outputs still available. I guess though, one of the big advantages of the DAC chip is that it might be smaller in actual board space outline than all of the Rs and Cs for the filters. Anyway, just a thought, as I am planing on basing a stand alone board on the replicape design. A simple cape will be used with only buffers for the STEP/DIR and SPI port (and a fault signal) all sent through an IDC26 ribbon cable to the main drive board. The SPI will go to a dsPIC uC to handle Analog inputs, Limits switches, and software PWM generation (for both Vref and mosfet outputs). I’m planning on using the Allegro A9848 instead of the TI part, as I’m more familiar with it.


    • Jeff, that is an interesting idea and perhaps worth looking into. It does require some research, though and I am more eager to get the boards ready for production.
      If you are looking to cut costs, the Allegros are a good choice. Also, what drives the costs on the Replicape is the connectors. These are high quality and thus expensive, but in my opinion worth the extra $s :) I’ve been contemplating making a cheaper 4-stepper, single extruder version as well, but I haven’t gotten around to it. Let me know if you have any luck with the PWM-controlled ADC. Found this TI note on the subject :

      • Hi Elias,
        I totally understand wanting to get to production. What you have works, so go! I just thought I’d pass the idea along, since I plan on using it on my design. Since your design is very space conscious you might want to stick with the DAC

        Yes, I do want the cheaper drive. The Allegros perhaps are not as robust as the TI parts, but the price difference adds up quick on 5, and they should be adequate for a simple reprap type system.

        Since my main board isn’t so bound to the cape format, I have extra room and I plan on using 3.5mm screw terminals for motor connections.

        Anyway, I’m still playing with the design. When I get further along, I’ll let you know how it goes.


    • William, you are not the first to ask for support for Repetier, so there is obviously interest in getting that. I’ve looked a little bit at it, but it seems to be written in .net, which is not my favorite language.. The feature I was missing was the Ethernet support. If you can live without Ethernet or fix it, i see no reason to not support it. The changes in the “firmware” should be minimal compared with printrun/pronterface. So i guess the answer would be yes, there are plans for supporting Repetier and any other host software for that matter. If you want it done fast, I suggest you have a look at it yourself, shouldn’t take more than an afternoon implementing it : )

    • Chad, I got an e-mail from CircuitCo yesterday saying that they have finally gotten a stable 3.8-kernel and are ready to get going with the capes. Unfortunately it’s not up to me, or things would go a lot faster : ) (at least that is what I imagine)

      • Hi Elias,
        Patiently waiting for my replicapes! Any idea when I could get my hands on a couple? Or when they will be ready for the public? Thanks, Chad

        • Chad, the last I heard was that production was due to start in 2-3 weeks and that was one and a half week ago. I’m sorry for the delays, I can tell you, I’m as eager as you to get the capes out on the shelves! :)

  10. Elias, is it possible to modify your Replicape such that one could stack a second modified cape on your Replicape? We are working on a 3d printer monster that calls for 6 print heads and 3 heated build platforms. In total 11 steppers and 9 heating elements (6 for the hot ends and 3 for the build platforms). I am wondering if this is possible with one Beagle Bone. Any suggestions are welcome.

    • Chris, that should be possible, yes, but you will almost certainly have to sacrifice either the eMMC or the LCD/HMDI interface or both to get enough pins for the extra steppers. I think the easiest would be to make a new cape that stacks on top with the additional stuff you need. 6 more steppers requires either 12 or 18 pins, the PWM is adressable, so that can go on the same bus (I2C), just change the address for the second one. For the other DAC, you need an extra pin for the SS and you have to rewrite the SPI driver to handle GPIO SS or you could use trim-pots if it is the top-cape. You also need a way to connect the MISO from the last serial to parallel chip to the MISO on the second cape. Right now it is just floating, but I’ve thought about adding a pin for it, but haven’t seen the need before.. A monster indeed : )

  11. Elias, I’m designing a BeagleBone cape and I was looking over your schematic to see how/if you handled these design guidelines:

    - Do not drive any external signals into the I/O pins until after the SYS_RESETn signal is HI (3.3V).
    - Do not apply any voltages that are generated from external sources until SYS_RESETn signal is HI.
    - If voltages are generated from the VDD_5V signal, those supplies must not become active until after the SYS_RESETn signal is HI.

    It looks like you are running off of the VDD_5V and you are applying voltages to pins which will be high before the SYS_RESETn pin goes high. Have you experienced any issues with previous versions of your board that might result from violating this requirement? I’m guessing it might not be as critical as the design guidelines imply (hopefully) as buffering all my signals or powering off of the system 5v isn’t very convenient!

    By the way, you might want to increase the width of your thermals on X2 pins 3 and 4, they look a bit skinny. You may want to disable thermals entirely (although soldering will be harder!) but that would more closely match the current-handling capability of your thick traces on the top layer.

    • Ethan, thanks for the tips on the thermals, I’ll look into that!
      I have not experienced any issues during start-up so far. It might be the case that this is all handled by the PMIC on the Bone. I’ve not looked at the timings for the PMIC lately, but as far as I remember the +3.3V is on a separate DCDC output, so this might already be handled if the 3.3V line on the header is used. Just an idea, but maybe worth looking into..

  12. My company would like to help out — if you buy the parts for 22 units, we’ll purchase the PCBs and assemble 20 units of your next version (or this version) for free.

  13. Hi, I need informations about Replicate.
    I have a BeagleBone and I would like to build a RepRap with your module, but can not figure out if the project is working or if you are still in progress.
    I have not found videos and sites that sell your card. Can I have information about it?
    A curiosity: can you drive the stepper motors in ramp?

    • Davide, the project is indeed still in progress! I have just received a test-batch of 20 Replicapes that are awaiting testing and shipment. Unfortunately, they have all been sold, so if you are looking to buy a Replicape, you will have to wait until the next batch is ready. I’m having a meeting today to discuss the terms with the manufacturer and also with a distributor. Hopefully the production will start in 4-6 weeks time. In the mean time, you can sign up for notification of when the boards are available for sale on

  14. I would love to try one out! Using MendelMax Pro w/ ramps. Would like to try my BBB with Linux cnc. How can I get one to beta test. Or purchase a kit/pcb?

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