The electronics that take the impulses from the computer and make the motors turn.
So I was planning on using an Arduino Due (more specificly an UDOO with an LVDS touchscreen) to control the Electronics.
I found the pinout here: ... structions
but it doesn't say anything about the logic levels? (signaling seems pretty straight forward though)
Do I need to keep all these pins within -15V to -3V for logic 0 and +3V to +15V for logic 1 (including the endstops) What are the tolerances for the electronics?
Also, how many steps can I send per second before skipping might occur?
Sounds too long :-(
Can I please be a beta tester and hopefully speed up the process for me and you? :-) If you provide me with a payment option and send me:
a) the schematics + part list or
b) the unsoldered board, the schematics and the part list or
c) the unsoldered board, the schematics and the components or
d) the finished untested board
I can assist in any testing / fixing / suggestions you want.

PS: I'm also going to add support for it in my new slicer:
I'll let you know.

The boards might ship on Monday, so we'd have them by the end of the week.

After I verify that they are ok, I will be happy to send you a kit for around $20.

The files are already online here:

But as they are untested, it is try at your own risk. I'd much rather lose money on a bad design then have you lose money.
Awesome, you rock :-D

I fully understand the risks involved, if anything brakes I'll just patch up the broken parts and try again. Money isn't lost if they are invested in fun! ;-)

I was quite surprised to see the Aruino D2-D7 being connected directly to the RS-232 (DB-25) ports 3,5,7,9,11 and 13. The reason I questioned this was because the DB-25 standard has -15V to -3V for logic 0 and +3V to +15V for logic 1. Will logic 0 work since you can not be driving a negative voltage on those pins? It sounds to me like it can be unreliable... or has your CNC controller other voltage levels for logic 0? Logic 1 should work with 3.3V on my Arduino Due, but it's not very high above the +3V threshold (unless your CNC controller have a lower threshold).

Looking forward to test your kit :-)
Actually. You're thinking of RS-232. That's serial.

Parallel communication is commonly IEEE1284. The data signals are 0 to 5v.. and sometimes 0 to 3.3v.

I noticed that the Due board is the 32bit board with the 0 to 3.3 logic levels. You might run into a problem, using it. The DIY board we have pulls up the signals to 5V. You might end up damaging the Due.

The controller itself can operate on 3.3v input signals as far as I'm aware... but this board is specifically for the Uno and those category of Arduinos running Grbl.

I might look into doing a Mega / Due version. I really want something that has an LCD and SD card and can run directly from the SD card as a "headless" configuration. It is still kind of the holy grail for low cost DIY CNC stuff. The 3d printer guys have had it for a few years now.
Oh, I was reading the wrong wiki page, just saw an image of the DB-25 connector and didn't know it was used differently in the different standards. :oops:

Thanks, that makes it a lot more easier, I guess I don't need a shield and can connect the pins directly. After all it's the Arduino which is driving all those pins, so there is no danger of getting 5V into the Arduino. Is this a valid assumption to make? That the controller board won't ever set the voltage on those pins? If so I'll just mash together something from what I have now. I'll make sure to connect the pins in the same way as you have so the software will be compatible.

(or I might just order a logic level converter like this, it's surprisingly cheap: ... cgodUHUAiA#.)
Hopefully that is true.

The controller is only listening on those pins. Though feedback and problems can happen (murphy's law). You could opto isolate the controller if you are worried though.

One of the reasons why I would recommend starting with the Uno is the fact that the DIP chip is only a few dollars and can be easily replaced if it is damaged.

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