Liar’s 3D Printing: Multiple Colors With One Extruder

December 27, 2016 by Al Williams 12 Comments

Good 3D printers now have multiple hot ends. You ought to be able to print in different colors or print support material. However, a lot of us don’t have multiple hot ends. Turns out, you don’t have to have multiple hot ends to print in multiple colors. To accomplish that you need a lot of patience and the willingness to tell bald-faced lies. Don’t worry, though, you’ll only be lying to some computer hardware and software, so that doesn’t count.

You may have seen people talk about putting a pause between layers to switch from one color to another. That works, but it limits your options. For example, if you want to put some colored text on a different colored background, you have to either have the text poke out, or it has to be “under” the background. It can’t be flush if you only have a single extruder and hot end. My method is a lot more trouble, but it can generate good results.

Keep in mind, with hobby-grade printers, multiple color printing has a lot of problems even if you do have multiple extruders. This isn’t a panacea. But you can get results on par with a similar printer that has multiple heads.

Bottom Line Up Front

Here are a few pictures of test prints that use this technique. A Monoprice Mini printer with the stock extruder and hot end created them using different PLA filament. On the left is a test cube, with a color spot in the middle of the layers (as well as some spots on the top surface you can’t see). To the right is a plate with my call sign in a contrasting color. It is hard to tell in the picture, of course, but there is one surface. The text is at the same height as the yellow surface.

I didn’t spend a lot of time making these prints since I was more focused on perfecting the methodology. The layer heights aren’t very fine, the infill is sparse, and the print speed was fast. However, you could invest time into making better-looking prints. You can also use the usual techniques that you use with a “real” multi-extrusion printer (such as priming towers, ooze shields, etc.).

Continue reading “Liar’s 3D Printing: Multiple Colors With One Extruder” →

Creating A PCB In Everything: KiCad, Part 3

December 23, 2016 by Brian Benchoff 19 Comments

This is the third and final installment of a series of posts on how to create a PCB in KiCad, and part of an overarching series where I make the same schematic and board in dozens of different software tools. A few weeks ago, we took a look at making a schematic in KiCad, and more recently turned that schematic into a board ready for fabrication.

For our KiCad tutorials, we’ve already done the basics. We know how to create a PCB, make a part from scratch, and turn that into a board. This is the bare minimum to be considered competent with KiCad, but there’s so much more this amazing tool has to offer.

In part three of this KiCad tutorial, we’re going to take a look at turning our board into Gerbers. This will allow us to send the board off to any fab house. We’re going to take a look at DRC, so we can make sure the board will work once we receive it from the fab. We’re also going to take a look at some of the cooler features KiCad has to offer, including push and shove routing (as best as we can with our very minimalist board) and 3D rendering.

Continue reading “Creating A PCB In Everything: KiCad, Part 3” →

Disassembly Required

December 23, 2016 by Al Williams 29 Comments

If you really want to hack software, you are going to face a time when you have to take apart someone’s machine code. If you aren’t very organized, it might even be your own — source code does get lost. If you want to impress everyone, you’ll just read through the hex code (well, the really tough old birds will read it in binary). That was hard to do even when CPUs only had a handful of instructions.

A more practical approach is to use a tool called a disassembler. This is nothing more than a program that converts numeric machine code into symbolic instructions. The devil, of course, is in the details. Real programs are messy. The disassembler can’t always figure out the difference between code and data, for example. The transition points between data and code can also be tricky.

When Not to Use

If you are coding your own program in assembly, a disassembler isn’t usually necessary. The disassembly can’t recover things like variable names, some function names, and — of course — comments. If you use a high-level language and you want to check your compiler output, you can easily have the compiler provide assembly language output (see below).

The real value of a disassembler is when you don’t have the source code. But it isn’t easy, especially for anything nontrivial. Be prepared to do a lot of detective work in most cases.

Continue reading “Disassembly Required” →

Tools Of The Trade – Thermoforming

December 22, 2016 by Bob Baddeley 11 Comments

Chances are good that you’ve already lost some blood to thermoforming, the plastics manufacturing process that turns a flat sheet of material into an unopenable clamshell package, tray inside a box, plastic cup, or leftover food container. Besides being a source of unboxing danger, it’s actually a useful technique to have in your fabrication toolchest. In this issue of Tools of the Trade, we look at how thermoforming is used in products, and how you can hack it yourself.

The process is simple; take a sheet of plastic material, usually really thin stuff, but it can get as thick as 1/8″, heat it up so that it is soft and pliable, put it over a mold, convince it to take all the contours of the mold, let it cool, remove it from the mold, and then cut it out of the sheet. Needless to say, there will be details.

https://commons.wikimedia.org/wiki/File:Thermoforming_animation.gif

Continue reading “Tools Of The Trade – Thermoforming” →

Harrowing Story Of Installing Libreboot On ThinkPad

December 16, 2016 by Bryan Cockfield 59 Comments

As an Apple user, I’ve become somewhat disillusioned over the past few years. Maybe it’s the spirit of Steve Jobs slowly vanishing from the company, or that Apple seems to care more about keeping up with expensive trends lately rather than setting them, or the nagging notion Apple doesn’t have my best interests as a user in mind.

Whatever it is, I was passively on the hunt for a new laptop with the pipe dream that one day I could junk my Apple for something even better. One that could run a *nix operating system of some sort, be made with quality hardware, and not concern me over privacy issues. I didn’t think that those qualities existed in a laptop at all, and that my 2012 MacBook Pro was the “lesser of evils” that I might as well keep using. But then, we published a ThinkPad think piece that had two words in it that led me on a weeks-long journey to the brand-new, eight-year-old laptop I’m currently working from. Those two words: “install libreboot”.

Continue reading “Harrowing Story Of Installing Libreboot On ThinkPad” →

A How-To In Homebrew Design, Fab, And Assembly With Structural Framing Systems

December 14, 2016 by Sonya Vasquez 42 Comments

At this point, the internet is crawling with butt-kicking homebrew 3D printers made with extruded profiles, but it’s easy to underestimate the difficulty in getting there. Sure, most vendors sell a suite of interlocking connectors, but how well do these structural framing systems actually fare when put to the task of handling a build with sub-millimeter tolerances?

I’ve been playing around with these parts for about two years. What I’ve found is that, yes, precise and accurate results are possible. Nevertheless, those results came to me after I failed and–dry, rinse, repeat–failed again! Only after I understood the limits of both the materials and assembly processes was I able to deliver square, dimensionally accurate gantries that could carry a laser beam around a half-square-meter workbed. That said, I wrote a quick guide to taming these beasts. Who are they? What flavors do they come in? How do we achieve those precision results? Dear reader, read on.

Continue reading “A How-To In Homebrew Design, Fab, And Assembly With Structural Framing Systems” →

Compiling A $22 Logic Analyzer

December 13, 2016 by Bil Herd 26 Comments

On my way to this year’s Hackaday SuperConference I saw an article on EE Times about someone taking the $22 Lattice iCEstick and turning it into a logic analyzer complete with a Python app to display the waveforms. This jumped out as pretty cool to me given that there really isn’t a ton of RAM on the stick, basically none that isn’t contained in the FPGA itself.

[Jenny List] has also written about the this application as created by [Kevin Hubbard] of Black Mesa Labs and [Al Williams] has a great set of posts about using this same $22 evaluation board doing ground up Verilog design using open source tools. Even if you don’t end up using the stick as a logic analyzer over the long haul, it’ll be very easy to find many other projects where you can recompile to invent a new purpose for it.