Sunday, May 17, 2009

software stuffs.

I actually got into this project through the arduino microprocessor that the newer versions of the reprap electronics use.

I was struck by all of the art/hobby uses of the arduino and its clones across all sorts of different areas. from plants that can tweet when they need water, to a simple robotics platform. It's inexpensive, a breeze to program, and there are so many different physical packages, that you can certainly find one that fit's well with your project.

The newer versions of reprap electronics use the arduino platform, and the associated programming environment. It has done wonders to make the project more accessible to people who may have difficulty with such thigs.

Anyway, I wanted to mention a bit about the software side of the reprap project. Personally, I'm a very mechanically minded person, it's what I studied in college, and I can even hold my own electrically too. Basically, they are physical systems and I understand those easily, I can visualize voltages and torques and balance and currents, I can see when something I put together probably won't work. I'm also pretty good at seeing how things might/will fail, and that's what I do in my day job, actually.

When it comes to programming, however, I have a hell of a time keeping variables and functions straight. I've spent plenty of time dealing with more simple languages, BASIC back on my commodore64 as a kid, HTML/general web stuff in high school, C and C++ in college. I've been wowed as to what some reprappers have been able to do, specifically some of the JAVA and PYTHON work.

At some point, once you've decided that you actually want to build and run one of these things, you need to sit back and take stock of what you need to download/purchase/learn. Like i mentioned in a previous post, there are many options mechanically, and there are actually a few on the software side as well. Personally, I use a mac, which happens to be one of the less common platforms used. Linux and windows seem to be the defacto standards, and there is some tough going for mac users. There are options, but one in particular, the JAVA host software I linked to above, doesn't seem to work yet on OS X.

The tool path is this: 3d model in STL (and it seems like it is now possible with STEP files too!) is sent to the Skeinforge "slice and dice" program to be converted to gcode instructions for fabrication. These instructions are what the printer will follow to rebuild the solid layer by layer.

This gcode file then has to be fed into the printer's microprocessor. These are instructions like, "print a perimeter from (2.3, 4.4),(4.3,4.4),(4.3,7.8), (2.3, 7.8), and back to (2.3,4.4). then fill it with zig zaggy lines" This is slightly varying for every machine, line thicknesses for example, so there are pretty deep parameter fields in skeinforge to be adjusted. Normally, someone may use the standard host software. I don't have that option, but luckily there is another package available. This one is called ReplicatorG. It also seems to have some issues (i've heard accounts that it may hoard resources on the computer if you are doing very long prints) but it does what i need it to do. i can jog each axis, and run the heater and extruder motor manually. I can then load a gcode file after conversion in skeinforge, and it then feeds those instructions to my system. i'm not quite there yet, but right now it looks like everything is coming together.

My apologies for all this, if anyone has read this and my previous posts i hope you got some thing out of it. i do plan on doing some shorter, more frequent posts with my own specific build details, but it feels like i should do some kind of service to people just getting involved in the project. paint some big broad strokes in one place, to at least get you started. everyone has probably tried finding some specific information in a message board site, and the search output is usually terrible.

best of luck if you're inclined to try some of this stuff.

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