[Retroplayer]

Yep cars the same thing. One of my businesses was a Honda motorcycle dealership and I loved the old bikes. I have 20 odd some 60's Honda's in my grody collection. I was a mechanic as a kid and worked my way through my 2 years radio technician degree (got the paper which Motorola wanted. The rest was mostly a waste of time). Always troubleshot my own cars. Still do if the dealership doesn't know what they are doing (Last time was a control problem on the 4 wheel drive 1997 F250. "Mr.Buddy you need a new 700$ computer". Didn't fix it of course and had to finally figure out what was really wrong. I digress. I don't even open the hood on my Prius.
Like you Retro No money as a kid (Did find the old family had had money but my father pissed them off in the late 40's and got ex communicated from the family). I grew up thinking I only had one set of grandparents and that hiding from debt collectors in the closet was a "normal" thing! I often think how grateful I am for my experiences and that I had no expectations except those I created for myself. Weird parallels when at 60 I discovered my "other" family from Boston and their influence on America.

OK so maybe Rolf and I need to start from the beginning. Man up, swallow prejudices and bite the bullet. First you type something into a keyboard into a program like laserDRW or openscad. It makes it's way through the software,sequences etc. and arrives as a digital word called a "G" code. I bet I can find a list of G codes on the net so that's just a lookup table. It presents itself "G code turn on beam" at the USB connector (or parallel, we get that I bet. Where does it go next ? Ramps, shield (isn't that just an interface board? could be wires and connectors?), Arduino? something else?

G-code is a text based set of commands. Like this:

M104 T0 S230

M104 is the command, T0 is the tool, and S230 is the parameter to set. In this case, I just told Extruder 0 to set the temperature to 230 degrees.

It is fairly standardized. However, the controller determines which codes go to what tool and what parameters to take.

In this case, this text string is sent to the controller (RAMPS in our example) over the USB serial connection. The code within the controller parses the string and then activates the appropriate output based on the tool, and moves it or sets it to the parameter.

So, in your laser cutter, you have X and Y steppers. So, you need movement g-codes, an axis for the tool, and the position as the parameter (G1 X100 = Move X axis 100mm). You also have a command to turn the laser on and off. The laser is the tool. A parameter of 0 is off and 1 is on.

But you don't really need to know this as that is all handled by the controller. And you use a program (like the slicer you use for your 3D printer) to convert the vectors or raster images into a set of G-Code commands. In our case, we use Inkscape and the G-Code plugin to do this for us.

The software G-Code generator does need to know some things about your controller. It needs to know what commands do what, what the names of the 'tools' are, and what parameters they expect. Again, though, all YOU really are involved in here is to use a matching software with a matching controller. You really do not need to know how it works.

As I mentioned, the hardest part is just changing one file in the source code for the controller to set it up for your machine. Things like steps/mm. This is how many pulses to the steppers are required to move the axis 1mm? You can either calculate that the hard way by pulley diameter, belt pitch, etc... or you can give it some default then command the movement 100mm, measure how much it actually moved, and use one of the numerous calculators on the net to find the real number. The Marlin firmware that goes in the RAMPS controller has the ability to set these things later. So you don't need to know it at the beginning and you can change these things whenever appropriate without going through all the firmware customization again. It stores this information within the controller memory.

Thankfully, for the K40 at least, someone else has already added the RAMPS to their K40. So they have already modified the firmware for you and set all this up. All you need to is upload it to the RAMPS and go.

[buddydog]

Is marlin the program you use to set the firmware? If so how does it get from your computer into the ramps? Do you move a jumper to program position or something? What is the arduino and shield?

[buddydog]

Also thank you for taking the time for this.

[Retroplayer]

Is marlin the program you use to set the firmware? If so how does it get from your computer into the ramps? Do you move a jumper to program position or something? What is the arduino and shield?

Marlin is just the code name for the firmware. When you download Marlin, you get a directory with many files with names like config.h, main.cpp, etc... these files are the actual code that runs on the Arduino. The Arduino is a microcontroller board. Arduino - ArduinoBoardMega

This board has a bunch of expansion headers on it that allows to you to connect various hardware and then you write programs to control the hardware. A shield is a board that plugs into those expansion headers. In this case, that shield is RAMPS RAMPS 1.4 - RepRapWiki

On the RAMPS board, there are more headers. These are for the Stepper driver boards. The A4988 is the popular choice and allows up to 16 microstepping (meaning 16 pulses per step - so a stepper that has 200 steps per revolution will have 200*16 actual positions) Microstepping increases the resolution as well as increases holding torque because the stepper is receiving current during mid step.

An ideal drive for a stepper is a sine wave on each coil exactly 45 degrees out of phase from each other. Since a true sine wave in the digital world is not possible, we use microstepping. The more microsteps we have, the closer it is to an actual sine wave.

In my system, I will be using the DRV8825 driver boards. These do 32 microsteps.

So, a recap: You have the Arduino. You connect the RAMPS shield on top of the Arduino. And in the shield, you insert the stepper drivers boards. All plug in.

The Arduino connects to the computer via USB. Already on the Arduino is a piece of firmware called a bootloader. This allows the Arduino to communicate with the computer over USB. The bootloader just sits there and waits for a an upload command to program the main firmware.

We use a program called Arduino IDE to load the Marlin source code and tell it to compile (make a single binary file) and upload to the Arduino Mega board. When it is done, you now have a controller board that accepts G-Code and controls steppers, extruders, monitors temperatures, etc...

You don't need to move a jumper to program because there is special sequence that the bootloader waits for to enter programming mode. If it doesn't get that sequence within a certain amount of time, it just transfers to the main program (Marlin in our case.) Because of this bootloader, you can load and reload the firmware whenever you want over USB to update it. For example, if you tweak the code to add some feature. You just compile again and upload the new firmware.

The RAMPS shield also has connections to add on an LCD screen with a buzzer, a knob, and an SD card. This present a menu interface to the user to perform some actions like jogging the motors without needing to use the PC. The SD card allows you to place G-Code files on it and print/cut without the computer.

Sound overwhelming? Well, realize this: The Arduino is already built for you, the shield is already built for you, the driver boards already built, and the LCD etc... already built. The Marlin firmware is already written for you.

All you are doing is plugging everything together, loading up code you don't really need to understand to get started, and uploading it to the Arduino. And you have a fully functional Laser controller.

[Retroplayer]

Step by step:

1. I bought this kit: Ramps 1 4 Mega 2560 R3 12864 LCD Controller 5pcs DRV8825 Driver | eBay
Which includes the Arduino mega, the RAMPS 1.4 shield, the LCD screen with SD card, and 5 pieces of DRV8825 stepper drivers (we only need 2 - 3 if we add a Z table).

I plugged the RAMPS shield into the Arduino, installed two of the stepper driver boards in the X and Y sockets. I connected the cables going to the LCD board.

2. Download the Arduino IDE: Arduino - OldSoftwareReleases (version 1.05 is known to work) and install it to C:\Program Files\Arduino

3. Plug in the Assembled RAMPS controller to your computer using USB. It will find and install the drivers for it.

4. This guy: Adventures in DIY Engineering: 40 Watt Chinese CO2 Laser Upgrade with RAMPS & Arudino
Modified the Marlin laser cutter firmware created by Lansing Maker Network to fit the K40 laser cutter.
You can download it at: https://drive.google.com/file/d/0B8S...oxaVBJNjQ/edit

Unzip it to a folder. Remember where...

Inside this folder, you have a folder called ArduinoAddons and a folder named Marlin.
In the ArduinoAddons folder is 3 more folders. You only need one of them. It is named "Libraries". Copy the contents of this folder to C:\Program Files\Arduino\Libraries

Then copy the Marlin folder to C:\Program Files\Arduino\Projects

5. Start the Arduino IDE program. You need to do a couple of things first to tell it which board you are using and on what serial port.

To determine the serial port, you can go to the device manager in windows. It should be labeled "Arduino Mega" or something like that.

In the Arduino IDE, click on Tools, then Board. Select "Arduino Mega 2560 or ADK"
Also in Tools, click on Serial Port and select the COM port that the arduino is attached to. You discovered this above in the device manager.

6. In Arduino IDE, click on open and navigate to the folder that you copied Marlin. Select "Marlin.ino"

After it loads, click the Arrow in a circle icon in the Arduino IDE to upload the code. When it is done, it will reset the RAMPS board.

That's it. You now have a RAMPS 1.4 controller with the customized laser cutter firmware installed. You will notice on the LCD that there is a menu you can navigate with the rotary knob. This provides status information while cutting, allows you to select files from the SD card to load and run, and has some settings you can change including the power of your laser.

7. You need to wire this board up to your laser cutter, replacing the existing controller. Those links I provided earlier cover that or I will be covering it in more detail myself as soon as I get to it.

But, the simple gist of it is that you have two steppers that will get connected to the X and Y connectors on the RAMPS. You have X and Y endstop switches that gets connected to the X and Y endstop inputs on the RAMPS. You have a laser on/off signal to connect between the RAMPS and the laser power supply. A connection between the power control input on the laser power supply and the RAMPS shield. And of course power to the RAMPS board for the stepper motors and the board itself. Not too bad.

These are the guys that created the original firmware and made the plugin for Inkscape:
equipment:buildlog_laser_cutter [Lansing Makers Network Wiki]
This is the guy that started things fitting all this to the K40 laser cutter: Adventures in DIY Engineering: 40 Watt Chinese CO2 Laser Upgrade with RAMPS & Arudino

Both of those links also cover how the RAMPS is wired to the laser cutter. If you are going to use the 24V from the laser PS, there are some things you need to take into consideration. This is also covered in those links.

[Retroplayer]

Just to avoid some confusion about firmware terms:

Marlin is a firmware designed for 3D printers.
The Lansing Maker Network built their own laser cutter and modified the Marlin firmware for laser cutter use.
The Adventures in DIY guy further modified THAT firmware to work with the K40 laser cutter.

So, the K40 customized firmware is 2 levels removed from the original/official Marlin firmware. The official Marlin firmware will not work as-is on the laser cutter.

Unfortunately this also means that the K40 firmware is locked into whatever version of Marlin the author was using at the time. Any future bug fixes or improvements to the main Marlin code will not make it into the K40 code. The solution would be to have a "fork" of the official Marlin firmware. Advanced programmer jargon. This is something I plan to spend some time on once I get everything up and running. I also want to improve the LCD menu code, add some more features, and eventually design a new shield to replace the RAMPS controller that is more special purpose and plug-and-play for the K40 laser cutter. This is not a simple effort and will take considerable time. So for now, I am only interested in getting the K40 up and running and the above steps will do that. It is "good enough" for now.

That's the real beauty of using an open source controller. I can take advantage of other people's work to get a functional controller going, but then take my own time experimenting and improving it. If I fail, I simply reload the code above back into the cutter and I am functional again. No harm.

I also have some plans to further improve a PC program to control the cutter and send G-Code. Some plans for using an Android tablet or similar as the standalone PC and other improvements. But all of these are future plans not needed to get up and running and enjoy the laser cutter.

[buddydog]

Excellent post Retro. I think a glimmer of understanding is coming. I have the setup you are describing on my Makerfarm and put the wires together as you described. In a B person way I get it I think. I'll try this:
The whole package (minus drivers and LCD panel) is the "arduino"
Marlin is the firmware (actually downloadable software but resides in prom in the Arduino?)
The shield is an interconnect board equivalent to wires between the ramps board and the Arduino board.

Just went and looked at the ebay parts and there are only two boards. So the bottom board is arduino and the plug in is ramps. Arduino is it house keeping (interface to stepper drivers, regulators, usb etc.).ramps is it the brains? Where the marlin resides,g codes interperated?

After a couple of more questions I will order one of those probably tonight. What software can I run this with that I know? Would there be a way to use openscad (I don't know those other inkscape etc programs)? If this will also work as a spare for my makerfarm it's a done deal. Only 71$ free shipping. When I upgrade toalarger machine I reallylike the idea of this because I want to keep all the same software nomatter how or what the hardware, and NO MORE DONGLES!

[Retroplayer]

Excellent post Retro. I think a glimmer of understanding is coming. I have the setup you are describing on my Makerfarm and put the wires together as you described. In a B person way I get it I think. I'll try this:
The whole package (minus drivers and LCD panel) is the "arduino"
Marlin is the firmware (actually downloadable software but resides in prom in the Arduino?)
The shield is an interconnect board equivalent to wires between the ramps board and the Arduino board.

Just went and looked at the ebay parts and there are only two boards. So the bottom board is arduino and the plug in is ramps. Arduino is it house keeping (interface to stepper drivers, regulators, usb etc.).ramps is it the brains? Where the marlin resides,g codes interperated?

After a couple of more questions I will order one of those probably tonight. What software can I run this with that I know? Would there be a way to use openscad (I don't know those other inkscape etc programs)? If this will also work as a spare for my makerfarm it's a done deal. Only 71$ free shipping. When I upgrade toalarger machine I reallylike the idea of this because I want to keep all the same software nomatter how or what the hardware, and NO MORE DONGLES!

You more or less got it, but it got it backwards a bit. The Arduino is the brains. The RAMPS is the muscle. RAMPS has the parts and connections for the steppers, extruders, hot-ends, heated bed, etc... You are loading the Marlin firmware into the Arduino, not the RAMPS. The RAMPS is the "shield." No memory and no brains on it.

That ebay link should have also had 5 DRV8825 boards (the little boards) these are stepper drivers. They have a little pot on them to set the current for your steppers. They are on modules so they can be easily replaced if they blow for whatever reason.

It should have also included the LCD panel. This just plugs into the RAMPS board and gives you a display, a control knob, a buzzer, and an SD card socket. You don't "need" it, but it is very useful and allows you to cut from an SD card instead of always connecting the PC.

Here is what the display looks like running the Marlin Laser Cutter firmware:

Attachment 265268


Now, your specific questions:

1. Can you use Openscad? Hmm. The output of Openscad is an STL file. STL is a a series of defined triangles making up a 3D object. The laser cutter is 2D. It *could* be possible, but would require a program that would generate the G-Code tool paths from the STL file ignoring the Z axis. I don't think anything currently exists to do this, but it is not impossible.

For a laser cutter, remember we are working in 2D. There is maybe a 2.5D argument given the depth of the cut based on power or speed (engraving vs. cutting) but there isn't really a whole lot of tools out there that really handle this for you. One of my future projects.

It is better to use 2D programs for the designs. Inkscape is like CorelDraw, LaserDraw, or Autocad. It is just a 2D drawing program. And it is freeware and open-source.

Your tool-chain for laser cutting is this:

1. Design in 2D, output DXF or SVG or whatever
2. G-code generator (this is like the slicer for your 3D printer. It parses the file and generates the toolpaths and spits out G-Code.)
3. G-Code sender. This is what Pronterface does for example. Pronterface doesn't really care what is inside the G-Code, it simply represents it visually on screen and sends the G-Code over the serial bus line by line.

So, your expectations should be that the actual workings won't be much different than what you are already doing. It's not ideal yet. But changing this up does allow you to work with more formats and use different tools for generating your design. You can use a CAD program, make up your design, export it to DXF and load that into Inkscape. Then use the Inkscape plugin to generate the G-Code.

Once you have the G-Code, you can either throw it on an SD card and plug it in to the LCD board or you can use Pronterface to send the G-Code over USB.

You'll notice that the tool that is the real bottleneck here is the "slicer" or g-code generator. That is what needs to really be improved to make this all a seamless experience. But there are many open-source programs out there which does most of the work and just need to be customized for laser cutting. Again, this is my future plans as well as a custom Pronterface frontend. The end result will be much like ELaser showed you with that controller in the other thread. We are not there yet, but it is very achievable.

(I have a habit of giving too much information, don't I?)

Let me know if anything was not clear.

[Retroplayer]

Wait... openscad does export DXF files and Inkscape imports DXF files. So yes, you should be able to use it.

[buddydog]

Ok Retro. The pressure is on! I ordered that unit. $72 with shipping! It fits my makerfarm (great 3d printer!) so a good spare in case something goes wrong with mine, I will play with it and try to learn stuff AND if I can bring it all together replace my K40 board. On that I will want to be able to switch back and forth at will from DRW.Just switch steppers, end stops, laser fire. Should do it.

[buddydog]

I tried to download IDE 1.05 as you said above and it does not exist.There are several versions 1.5?
edit: maybe you meant 1.0.5 I'll try that.

editk did it.There is a icon on my desktop. It opens a program which has a bunch of stuff in it.

Iguess now I wait for the arduino to show up and then download something into it from the IDE program?

What is inkspace?

openscad has a 2d function so maybe that can create stuff. Then on to ? the slicer? then to the camera card and then into the arduino LCD like I do with my makerfarm. Anyway to use cura?

[Retroplayer]

I tried to download IDE 1.05 as you said above and it does not exist.There are several versions 1.5?
edit: maybe you meant 1.0.5 I'll try that.

editk did it.There is a icon on my desktop. It opens a program which has a bunch of stuff in it.

Iguess now I wait for the arduino to show up and then download something into it from the IDE program?

What is inkspace?

openscad has a 2d function so maybe that can create stuff. Then on to ? the slicer? then to the camera card and then into the arduino LCD like I do with my makerfarm. Anyway to use cura?

Yeah, 1.0.5 is what I meant. The next step would be to download the laser cutter firmware. Step 4 above:

4. You can download it at: https://drive.google.com/file/d/0B8S...oxaVBJNjQ/edit

Unzip it to a folder. Remember where...

Inside this folder, you have a folder called ArduinoAddons and a folder named Marlin.
In the ArduinoAddons folder is 3 more folders. You only need one of them. It is named "Libraries". Copy the contents of this folder to C:\Program Files\Arduino\Libraries

Then copy the Marlin folder to C:\Program Files\Arduino\Projects

That will get you prepped for when the RAMPS kit arrives. Once the kit arrives, assemble it as in Step 1

1. I plugged the RAMPS shield into the Arduino mega (big blue board), installed two of the stepper driver boards in the X and Y sockets (note the orientation). I connected the cables going to the LCD board.They will be labeled EXP1 and EXP2 on both boards.

And then plug it into your computer. Then do steps 5 and 6:

5. Start the Arduino IDE program. You need to do a couple of things first to tell it which board you are using and on what serial port.

To determine the serial port, you can go to the device manager in windows. It should be labeled "Arduino Mega" or something like that.

In the Arduino IDE, click on Tools, then Board. Select "Arduino Mega 2560 or ADK"
Also in Tools, click on Serial Port and select the COM port that the arduino is attached to. You discovered this above in the device manager.

6. In the Arduino IDE, click on File then Open and navigate to the folder that you copied Marlin. Select "Marlin.ino"

After it loads, click the Arrow in a circle icon in the Arduino IDE to upload the code. When it is done, it will reset the RAMPS board.

That's it. You now have a RAMPS 1.4 controller with the customized laser cutter firmware installed. You will notice on the LCD that there is a menu you can navigate with the rotary knob. This provides status information while cutting, allows you to select files from the SD card to load and run, and has some settings you can change including the power of your laser.

The firmware should then be loaded and your LCD will light up and display like my picture above.

[buddydog]

Thanks for your generous time on this Retro. I am looking forward to messing with this mainly cause I want to be more in control of troubleshooting these kind of things.

Rolf I stole your thread but is this helping at all with your original problem?

[buddydog]

Retro in step 4 above I find the file "librarys" but I don't know how to "copy"it? I right click on librays and I get a window but no copy or "send to" or anything like that. If I click librarys I get 3 more files: Liquid crystal, SPI and u8glib? Don't know how to "copy" them? I', guessing these are the stupid questions like telling someone to "measure the 5 volt line" and they ask " which setting on the meter do I use. AMPS?" !

[Retroplayer]

Retro in step 4 above I find the file "librarys" but I don't know how to "copy"it? I right click on librays and I get a window but no copy or "send to" or anything like that. If I click librarys I get 3 more files: Liquid crystal, SPI and u8glib? Don't know how to "copy" them? I', guessing these are the stupid questions like telling someone to "measure the 5 volt line" and they ask " which setting on the meter do I use. AMPS?" !

This might be a dumb question, but are you sure that you unzipped the files? Because windows will treat a zipped file like a folder as far as browsing the contents, but won't allow you to do things like "copy."

Do you have a file called buildlog-lasercutter-marlin-master.zip that you downloaded? If you didn't unzip it, right click on that file and chose extract to buildlog-lasercutter-marlin-master\

Then you will have folders which you can copy.

[buddydog]

I bet this is where both Rolf and I have trouble.You were right.I didn't unzip it so I did that via something called extract and I sent that to c users test. I found the library's file but when I try to send it to C:\Program Files\Arduino\Libraries I don't find that file. I tried to make a file called that but a message said I couldn't do that. I did manage to save it (5mb) to my desktop but I don't know how to get it to go to C:\Program Files\Arduino\Libraries which does not exist on my machine?

[Rolf_K]

{snip}

Rolf I stole your thread but is this helping at all with your original problem?

No problem, I'm learning a lot. Retroplayer's post "Step-by-step" is the type of instructions I have little or no problems following. I am grateful that he took the time.
By the way I contacted the seller of the item in my original post,several days ago, about the instructions he claimed was included with the sale, he has chosen not to reply.

[Retroplayer]

I bet this is where both Rolf and I have trouble.You were right.I didn't unzip it so I did that via something called extract and I sent that to c users test. I found the library's file but when I try to send it to C:\Program Files\Arduino\Libraries I don't find that file. I tried to make a file called that but a message said I couldn't do that. I did manage to save it (5mb) to my desktop but I don't know how to get it to go to C:\Program Files\Arduino\Libraries which does not exist on my machine?

That was why I said to give the Arduino IDE that directory when you installed it

It sounds like you have Windows 7 or 8, though. So you don't have a C:\PROGRAM FILES folder. Instead, you have a C:\PROGRAMS folder. See if an Arduino folder is in there.

[Retroplayer]

No problem, I'm learning a lot. Retroplayer's post "Step-by-step" is the type of instructions I have little or no problems following. I am grateful that took the time.
By the way I contacted the seller of the item in my original post,several days ago, about the instructions he claimed was included with the sale, he has chosen not to reply.

Yeah, I REALLY doubted you would get any support from them and whatever documentation you did get would be very difficult to understand because it would be translated.

[buddydog]

I do have 7. I think my head will explode. This is revisiting the dark place! :-) Ok I found a program files(86) (what the hell is 86 for?). Anyway I opened arduino file and then picked up the library's file from the desk top and dropped it on the arduino file and it acted like it did something but kept asking if I wanted to do something with each file. I said yes each time and it acted like it moved something and then at the end it flashed "Administrater required" or some such nonsense and then ended.I deleted the library's file from the desktop. I was a tee totaler my whole life but I'm gonna go have a glass of whiskey!