Hi all,

I'm working on a 3D printed pen plotter but I'm struggling to decide on which controller and firmware to use.
A while back I picked up an Uno, CNC shield and some tmc2208 drivers.

Most DIY pen plotters I've seen are running standard GRBL (CNC Mill) or LaserGRBL firmware.
Is there a GRBL based firmware that is specifically for pen plotters with a servo Z-axis?

I would really like it if the plotter could be run independently of a pc either via SD card or Wi-Fi, and had some sort of interface screen.
Is there a way I can do this with the Uno and CNC shield? Or do I need a more modern 32bit controller?

I noticed the Makerbase MKS DLC32, Could this be configured to have a servo z-axis?

Or am I better off forgetting about GRBL and going down the marlin and ramps route?

Sorry for so many questions! I find the CNC/laser controllers fairly confusing coming from the marlin world.

... it's some (tens) years now, when I was last busy with controlling pen-plotters or similar -- last used Marlin4Due+Pronterface and RADDS (similar to RAMPS, but for the ArduinoDue)

---

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

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

Hi VDX,
Sorry for the slow reply, I've been doing a bit of research into some of the options available.
I found one of the MKS DLC32 v2.1 boards on aliexpress for £7.50 with free shipping, I had to give it a try at that price!

The DLC32 has some really nice modern features:-
Wi-Fi and Bluetooth (can use phone or tablet for control)
A few different touchscreen options
3x Standard stepstick sockets (dip switches rather than jumpers)
32bit processor
Can run GRBL & LaserGRBL
SD card socket & Blade fuse for the PSU

I also ordered a nema8 stepper (20x20x34mm) for the Z-axis, hopefully it will be strong enough to actuate the pen.
Originally I was planning on using a servo to keep weight down but I think it would have been more trouble than its worth and a bit slow.

The design I'm working on slings the paper back and forth on the Y-axis just like a traditional drawing room pen plotter.
I need to find a way of sensing the leading or trailing edge of an A4 sheet of paper to be the Y-axis limit switch.
Do you know if those common optical end-stop's with a red PCB would trigger from a single sheet of paper?
Like this one:-
[ooznest.co.uk]

I fear the UV may pass straight through a single sheet but not too sure.
Can you think of a good way to sense the edge of an A4 sheet?

P.S. Should I use GRBL or laserGRBL for a pen plotter?

... AFAIK the LED's, used in this type of optical switches are IR, not UV ... but should be sensitive enough to get activated by a paper sheet.

Another methode, used for detecting paper on a black roll, is using reflexive optical sensors - here an amazon search:

[www.amazon.com]

LaserGRBL could be slightly easier, as a pen is something similar in use to a laser with the ON/OFF per line or polyline

---

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

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