Update 19/04/2016:
MarlinKimbra is here!
This is one of the best firmwares based on Marlin I have seen for a long time, no feature is missing.
But for our purpose here it is just about being up to date and getting better results.
Please check the last step of this Ible as I will keep future updates there.
Download, Liaocheng shenhui laser equipment Co.ltd. Add:No.28 Huanghe Road,Liaocheng City, Shandong,China 252000.
Update 11/04/2016: The new firmware is available now in my Ible about 8bit engraving.
This means the power level is now from 0 to 10000, giving a higher resolution for the power without compromising speed or other functions.
Engravings on fragile things like paper are now possible without burning holes.
All SD and display functions have been modified to suit the firmware, so you can move the head, do testburns at various power levels and even tweak most of the settings to be totally independant from a PC / laptop.
I tried my best to implement WiFi as well but could not get it working properly, so if you do want to transfer your Gcode files without swapping the SD use a WiFi enabled SD card instead.
Never tried it due to a lack of hardware but it should also work using Octoprint.
Update 27/02/2016:
True 8bit photo engraving is now possible, please check the addition here.
Update 26/02/2016:
I was able to change the Marlin code so that now a much higher resolution for the Laser PWM signal is possible.
Please beware that I also found a problem in the code.
The curent power settings are not deviced in 256 steps but limited to 100 - reflecting the original machines 0-100% settings!
I will do some tests on the weekend and if all good upload the modified firmware for everyone interested to test.
With that it should now be possible to do true 8bit engravings with a CO2 laser - something even Picengrave can't do at this stage.
I will also add links to the software used to used to generate the code the true greyscale engravings and how to modify the Gcode for proper placement on the machine. - Stay tuned!
When it comes to starting with CO2 lasers the beginner on a budget will be tempted to get one of the K40 clones from china.
As requests, problems and postings of general frustration about these machines flood the internet I though I jump in too.
Don't get me wrong, I did it on purpose as the price for the entire machine was about the same as just a 40W laser tube imported to Australia - and that is without a power supply...
I already started a topic in the forum on why not buy them but if you already did or still want to get one, this Ible might be helpful on your way.
What you will get in this Instructable:
All the info, sofware and tips you need to convert your budget laser cutter to run on an Arduino board - for far under 50$.
Also the satisfaction that you can now create all your things directly in Inkscape (or other vector programs).
What you need, tools, and such:
1. Patience...
If your machine is anything like mine you don't want to rush things as not everything is perfect in China.
2. A basic understanding of wiring some cables and some very soldering skills.
3. Basic toolset.
Flat and phillips head screwdriver, 7mm spanner (keep the set at hand, you never know...), pliers, side cutters, soldering iron, heat shrink tube or if in doubt electrical tape.
4. Arduino Mega with Ramps board, optional a display with encoder and SD support to have a stand alone solution.
5. Some old computer cables, connectors and such - I tried to keep the original cables the way they are, it is no problem not to use connectors and to solder directly.
The only thing I really suggest using connectors fo is on the pins for the ramps board, I used single LED pins from an old computer.
You can source the complete kits including Ramps and stepper drivers for around 30-40$ either through Ebay or your trusted local dealer.
6. Two 10kOhm resistors.
First to the specs:
40W CO2 laser - claimed power, so we can assume it is around 30W when you would measure it.
Unlike most of them I got mine with a digital power control and not the analog meter with potentiometer.
Rest is like any other chinese clone out there except the electronics...
Here can already make out if you might get some fun out of it or not.
Mine came with the totally outdated 'Corel Laser draw', from 2013 and with a golden dongle.
Others have newer software and other dongle colors, indicating a newer control board.
The 2016 versions also support vector cutting and speed/power settings by line color definition (but they cost more and are very hard to find).
So unless you got the latest model you will most likely have it shipped with Moshi Draw, Corel Laser Draw (2013-2014) or in very rare cases with real software like you would find on high end machines - again for a much higher price.
Corellaser Windows 10
Is this Ible interesting for me and does help my machine?
If you can only do engravings and cuts with raster images like BMP,JPG,TIF,PNG but not in any vector format then it can help you.
If your machine and software already come with full vector support and a print driver to use it with any software out there you might want to find other reading material.
Although some of the mods might be of interest to you anyway... ;)
I will start with some basics of the crippled stuff and how to improve your work a bit but the real deal starts at step 4 with the replacement of the controller board.
Corellaser Plugin Download
Plugin Download Chrome
Can I use it for something else?
Of course you can!
As it is a 'generic' approach this mod can also be used on your homemeade diode laser engraver.
You will need to modify the Marlin firmware to suit your needs though in terms of endstops, buil dimensions and such (easy!).
Info on the above images:
The pegasus was engraved on cheap, 3mm plywood - not a good choice LOL
My niece was engraved on plywood too but with the original Turnkey release and before the full 8 bit support was added.
And the old movie image with Billy the kid was engraved on Arakaria wood with the latest firmware mods.