Laser cutter Buildlog: Arduino and RAMPS

This post can be considered a work in progress. It'll be upgraded as I discover new problems that other users are having. Last update: Aug 20th, 2015

 I use a fork of the 3D printer firmware called "Marlin" on my Arduino MEGA to control my laser. Specifically, I use a fork by the user Turnkey Tyranny available here. I use Inkscape for all of my design work, as well as Turnkey Tyrannys fork of an Inkscape plugin designed to export G-code suitable for his firmware.

If you have never used the Arduino IDE (software to upload firmware to Arduino boards) before please take the time to go through a few of the tutorials on the arduino.cc website.

Getting Started with Arduino

This will tell you how to install the IDE, and give you a general idea of how to upload new firmware. Once the Arduino IDE is installed, navigate to the folder where you unzipped Turnkeys fork of Marlin. Double click on "Marlin.ino" and it will open in the Arduino IDE with all of its associated files. If you use File > Open it may not load all the required files. Connect your Arduino via USB, make sure you have the right board selected in the IDE, and click upload. If you get a u8glib dependency error, you'll have to download the u8glib library and install it. U8glib is required if you are using an LCD panel. I highly recommend using an LCD panel as this allows you to use an SD card to run the machine, rather than have a USB cord running to your computer.

How to install new libraries for the Arduino IDE

Once you have Turnkeys fork of Marlin installed, and the RAMPS board and LCD stacked up, your LCD screen should turn on and look similar to this:

Now you're ready to start plugging everything into the RAMPS board, but FIRST and most important.. look on the RAMPS board for diode D1. You MUST remove this diode before wiring the laser cutter up. It will suffice to just clip the leads and remove the diode, but its a bit of a tight fit so I desoldered it from the back.

If you do not remove D1, then the RAMPS board will attempt to route 24v from the stepper circuits to the 5 volt regulator on the Arduno. It's not rated to step that much voltage, so it will fry and possibly ruin your Arduno MEGA.

Some buildlogs have suggested removing the yellow Polyfuses from the board as well, and bridging their connectors. I did not do this, and have not noticed any trouble even after running the machine for more than an hour one one design. You're mileage may vary. If you have issues with brownouts or the machine shutting down randomly, I would suspect the fuses may be causing some issues.

Using Inkscape with Turnkey Tyrannys plugin

If you've been following along you'll notice that I have been using Turnkey Tyrannys fork of an Inkscape plugin available here for my laser cutter design work. He has a nice set of instructions already wrote up on how to install the plugin, so I won't reinvent the wheel there. This post is more on how to go about designing and cutting your first part using his plugin, and a few things that I've picked up on in the last few months of using it.

Laser build log, part 3

I am so far behind on updating this.. I apologize. I've been focusing more on getting the machine running than I have documenting it. As it sits now, the machine is fully functional and pushing good test cuts. The past couple of weeks have been spent playing around in Inkscape using Turnkey Tyranys plugin. https://github.com/TurnkeyTyranny/laser-gcode-exporter-inkscape-plugin

I've also been using his version of Marlin, and the two play together very nicely. Turnkey is still working on the plugin, but its looking better every day.

I joined a google group (https://groups.google.com/forum/#!forum/opensource-laser) to talk with others who have done the same modification to their machine. We've also been discussing starting a Wiki for the K40 style lasers in order to document as much about them as we can, ie, power supply pinouts and wiring diagrams for an Arduino/RAMPS or DSP system upgrades. It should be nice to have everything in one central location for anyone to browse.

Once I get some more time, I may go back and edit the first couple of buildlog posts to clarify things. Rough drafts aren't my style, and I have horrible habits when documenting things for others.

I'm also very active in the Laser Engraving and Cutting group on Facebook. It is a closed group full of great members who use these machines every day. Many still use the Moshi board, and several have upgraded to a DSP system. If you're looking for a place to turn, it would be a great start.
https://www.facebook.com/groups/441613082637047/

Laser build log, part 2

The postal service has been pretty nice to me the past week. So far the only thing I'm missing the get the laser up and running is a replacement tube, which should be here around the second week of March. As of right now I have some LED strip lighting installed in the cutting bay, and my RAMPS module is all wired in with a small quickie jumper board to get my endstops set.

I need a shark and some duct tape...

Some of the best toys come in boxes that you cannot read. It also helps when said box is rather large.

I do have to say, I've been rather anxious for this to arrive. Its the largest thing I've ever ordered, thats for sure. Inside the box, was another box. Surprise! I'll spare the details, but once I got past the Matryoshka doll packing job I was greeted with my brand new 40 watt CO2 Laser engraver/cutter.