Working on a Raspberry Pi shield for DLP 3d printers

You can discuss various control electronics here. RAMPs, Arduinos, Motor Controller boards & etc...
ciclopez
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Joined: Thu Aug 07, 2014 4:03 pm

Re: Working on a Raspberry Pi shield for DLP 3d printers

Postby ciclopez » Tue May 19, 2015 4:15 pm

Nice to see other people working on similar projects, it looks very promising :)

Sorry, I don't know any chip that integrates multiple stepper drivers + controller all in one.
If you are looking for a motion controller alone to use with your Pololu stepper driver modules, I started my project using the TMC429-LI, it sends step/dir pulses for up to 3 stepper drivers, uses SPI as interface and handles the end-stop switches, maybe it works for you. I finally preferred to use multiple TMC5130 because the motion controller is integrated and simplifies the PCB, it can use SPI or UART as interface.

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PacManFan
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Re: Working on a Raspberry Pi shield for DLP 3d printers

Postby PacManFan » Tue May 19, 2015 11:46 pm

danielm wrote:Nice job! Let us know how it is performing.

I am working on something similar, however for galvo-based SLA/SLS systems. I am currently building first prototype - galvo control part is working, stepper and end-stop part is completely missing :) It is running on my own cloud-based software.

This is a short video of galvo setup scanning perimeter of object layer at approx. 4kpps: https://drive.google.com/file/d/0B2mvAu ... sp=sharing

I was not aware that stepper drivers with integrated controllers as TMC5130 are available. I will definitely consider it for my board. My intention was to equip the board with 2-3 positions for Pololu stepper driver modules. I did not test it yet, however I was expecting unsatisfactory performance without additional MCU. Is there something like TMC5130 but designed for multiple steppers controlled by single interface (SPI, UART)?


I'd like to state again that I've already added galvo support for a the LaserShark and partial support for the e1701 controller. I'd like to add support for your galvo controller as well.
-PacManFan

danielm
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Joined: Tue Jul 08, 2014 7:39 am

Re: Working on a Raspberry Pi shield for DLP 3d printers

Postby danielm » Wed May 20, 2015 4:10 am

ciclopez:
Thanks for the info regarding TMC429. It seems that this chip is what I was looking for. Already ordered 1pcs in SOP24 package for prototyping and 2pcs in QFN32 package. I would probably prefer QFN32 for production as only this version offers 2 switch inputs per all 3 steppers. Do you have any experience with hand soldering of QFN32?

Btw how do you perform chip-select for 3 SPI slaves from RPi? Do you use external multiplexer? Or combination of SPI and UART?

Good luck with testing :)

PacManFan:
My current SW stack consists of three components: Cloud server which does the slicing, Printer client which renders sliced data and Web-based GUI. I think in current state it would be hard to integrate. However, in the production phase I would like to provide small Python library which in my opinion could be used for integration into CW.

ciclopez
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Joined: Thu Aug 07, 2014 4:03 pm

Re: Working on a Raspberry Pi shield for DLP 3d printers

Postby ciclopez » Thu Aug 27, 2015 9:18 am

danielm wrote:ciclopez:
Thanks for the info regarding TMC429. It seems that this chip is what I was looking for. Already ordered 1pcs in SOP24 package for prototyping and 2pcs in QFN32 package. I would probably prefer QFN32 for production as only this version offers 2 switch inputs per all 3 steppers. Do you have any experience with hand soldering of QFN32?

Btw how do you perform chip-select for 3 SPI slaves from RPi? Do you use external multiplexer? Or combination of SPI and UART?

Good luck with testing :)


I solder almost everything using a toaster oven as a reflow oven and an external reflow controller, with solderpaste and an stencil, QFN32 is very difficult to solder instead. For the chip-select with 3 SPI, I use only one chip-select line and I daisy-chain the chips, this way I can send perfectly synced orders to the three steppers.