Rapberry pi and Gertbot

I already have a Raspberry pi 2 but I don't use it for 3d printing. I run a version of Linux on it.
There is however an even faster Raspberry pi 3 out now that I have just ordered. Some talk about being able to run Windows 10 on it in the future. I also notice there is an interface for it called a Gertbot that has four motor channels.

[www.gertbot.com]

I seems this would be suitable as a 3d printer controller.

Anybody had any experience of using the pi on the controller side?

... " It has four channels each capable of driving 30 Volts and 2.5A" -- this sounds for me like only two stepper motors can be run

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Viktor
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I have just read through the specs again. Yes you are right, 2 stepper motors per board.
But they are cascadable up to 4 boards in total, so 2 Gertbot boards would be needed to control 4 stepper motors.

Edited 1 time(s). Last edit at 02/29/2016 10:14AM by dave3d.

I believe the main problem with using a RPi directly as a printer controller is the OS -- Linux is not a real-time OS, so can't guarantee to deliver the pulses to the steppers at the right time. Some pulses may be delayed, whereas others aren't, so the speed may vary, perhaps so much that the motors might skip steps. How much a problem this is in reality, I don't know. There is a Linux variant called LinuxCNC which addresses this issue and which I think can be run on the RPi. I don't know how good that is.

But, given that the GertBot board has its own micro to control timing, this may not be a problem.

OTOH, at 40GBP per GertBoard, this is an expensive way to control a printer. An Arduino+RAMPS is less than US$20... add appropriate software on the Arduino (e.g. cut-down Marlin) and a high-speed data path between Arduino & RPi (assuming that 115K serial isn't fast enough) and you're done.

Here is a link with more details of the board:

[www.rs-online.com]

Motor control is taken away from the rpi and done by the onboard chip.
It looked suitable when I first read 4 channels but that equates to just 2 stepper motors, so unfortunately 2 boards are required totaling 80 GBP.

I presently have an Arduino/Ramps and I am looking round for something better.

BeagleBone is better suited for this type of control since it has the onboard PRUs to handle real-time tasks.

MachineKit and BeagleBone are standardizing on a kernel with real time extensions.

... I'm mostly using RADDS boards for my developments, but have some UDOO's too - quad-cores which I'm starting with linux or android ... and with an 'integrated' ArduinoDue on board.

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]