Cheap DIY Microscope Sees Individual Atoms

Simply too cool not to post. Admittedly you’re limited to only conductive materials, but who cares. It’s a scanning tunneling microscope you can make at home.

Hackaday

This is not an artist’s rendering, nor a physics simulation. This device held together with hardware-store MDF and eyebolts and connected to a breadboard, is taking pictures of actual atomic structures using actual measurements. All via an 80¢ piezo buzzer? Madness.

HAD - STM6 Gold atoms in a crystal.

This apparent wizardry is called a scanning tunneling microscope which takes advantage of quantum tunneling. The device brings a needle atomically close to the object to be measured (by hand), applying a small voltage (+-15V), and stopping when it starts to conduct. Depending on the distance between the tip and the target, the voltage varies and does so precisely enough to identify whether an atom is underneath or not, and by how much.

The “pictures” are not photographs like a camera might take from a standard optical microscope, however they are neither guesses nor averages. They are representations of real physical measurements of specific…

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Build a Prosthetic Hand – At Home!

Building off my prior post, if you’re at all interested in working with the good folks of E-Nable, I can’t recommend enough that you sign up, and then join the Google+ group.

They are doing some amazing work on that site, and it deserves as much recognition and help as possible.

But say you just want to make the hand? Maybe you need a decoration, or just want to show off the capabilities of your printer.

Check out the Raptor Hand by E-Nable then. Designed to be made almost entirely out of 3D printed parts, it’s a really fancy looking piece of kit, and a great test of your skills.

http://enablingthefuture.org/upper-limb-prosthetics/the-raptor-hand/

It’s particularly a good test of how your printer handles tolerances, and how calibrated it is. If things aren’t correct, the pins which snap the flanges and fingers together simply won’t work right (either falling out or not going in), and the “ligaments” won’t thread correctly. If you want to be even more futuristic, take a look at the limbitless arm, which is the only 3D printable open-source myoelectric arm that I can think of.

Stormtroopers and RIT Arms

0111TrooperArm MA7_0

When people talk about what’s amazing about 3-D printing, or what the killer app is, I think the most obvious applications are in medicine. The obvious application is custom manufacturing of complex medical devices; things like bones, joints, etc can be shaped to fit the patients requirements instead of the other way around, hopefully shortening recoveries and improving end-patient success.

However, when it comes to what really gets people excited, it’s prosthetics. 3D printing already does so much good here; whether it’s providing cheap prosthetics through the E-Nable project (which is extremely worth your time to join if you’re a printer), or by allowing patients to take ownership in pride in something, which unfortunately, has been a thing people hide.

“Sure, you might have a “normal hand”, but mine is a stormtrooper’s hand”, turns out to be one hell of a self-esteem boost for a child.

Just see below; thanks to the good folks at E-Nable, he was able to get a custom made RIT arm, which restores a degree of functionality to his arm, and more importantly, can be cheaply remade as he grows.

http://chronicle.augusta.com/news/health/2015-01-10/new-trooper-arm-surprises-augusta-boy

Just remember; we’re already living in the future.

-Meds

Experiments with POM

As mentioned before, the standard white masking tape I’ve been using lately has been a nice improvement over my prior tape of choice. It’s bond is so strong, and the filament adheres so well to it, that the slight amount of warping PLA creates has been more or less eliminated for me, without requiring a heated bed.

Given such great results, I thought it’d be interesting to try a run with some of the Acetal/POM filament I have on hand, and see how that works out.

Unfortunately, results were significantly less positive. These runs are admittedly a bit nicer than prior attempts, and at least the pieces are solid.

I’m inclined to believe that there isn’t really a way for me to get around the necessity of a heated bed for this one. Unlike nylon, which I’ve had minimal success in keeping adhered to the print-bed, the POM continues to pop off.

Polyoxymethylene, commonly reformed to as POM, or Acetal or Delrin has about the same shrinkage factor as PLA (approx. 2% give or take the filler content) so on its surface, you wouldn’t expect such issues, compared to a higher shrinkage rate polymer like ABS. Especially when PLA has to be heated to only about 185 C for good results, whereas POM requires 215 C minimum.

However, there’s a second factor coming in to play. As many of us have experienced, PLA retains a degree of heat after printing, often remaining relatively pliable and soft for some period after printing. This is because it has a relatively low crystallinity; it melts sooner, and it retains heat longer, because it is an amorphous material. It doesn’t set into an organized structure.

POM is highly crystalline by comparison; it naturally falls into a more “organized” state, which is part of why it has so many great properties (low friction, high durability) but is also why it is so hard to work with. It sheds heat quickly, cooling down into a solid within seconds of printing. When it is being printed, it becomes amorphous, and clear; upon cooling it becomes an opaque white as you can see in the photos above.

Because of this, it cools off so rapidly, that all 2% of its shrinkage occurs at once, instead of over a period of minutes like PLA. In turn, the material shears off the build plate, and curls inward due to contraction along the perimeter of the print.

As a result, there are likely only 2 ways to get solid reliable prints with PLA.

  1. Utilize a heated bed to provide enough heat to the print to slow the cooling rate down (likely somewhere around 80 to 140 C)
  2. Utilize a heated build chamber to slow the print’s cooling rate down.

The latter is what the $10,000 plus Stratasys machines do, and they have quite the nice patent on it. It’s also a lot harder to design. So, I think my shopping requirements for the next few weeks are pretty sorted out.

In the meantime, I will probably continue to see how it performs on other substrates. I’ve heard some mentions that it prints extremely well onto particle boards like OSB, so I might have a small wooden build plate laser cut for the purpose. I haven’t had a good opportunity yet to go up to the Metrix Create Space in town.

Funnels and Slic3r

At the beginning of the year, it’s often the time for projects, big or small. I decided that this was as good a time as any to make a few useful things for my car. I already have all the fluids I need to clean up my car. I just don’t have a funnel.

Rather than run across town to an auto parts store for a funnel to fill up the fluids in my car, I just made one, using this wonderful design I found on Thingiverse. Hat tip to bluesroq, for the great design.

You might also notice the tiny little funnel. Needed something to fill the flask from NYE. Hat tip to KKHausman for that design.

I think the more interesting thing I’ve observed, after extensively testing these funnels for their ability to be water-tight, is that it’s definitely a function of two factors, layer height (relative to the model size) and vertical/horizontal shell-count.

Bearing in mind that this is all slic3r specific, and so users of Skeinforge/Cura/Etc might not find this as handy. Shells are simply a representation of how many solid “walls” exist in the object when it’s being printed. In slic3r, these shells are represented as being either horizontal (perpendicular to the build-axis) or vertical.

If the object your printing is a cube, you could say, set your slic3r to have one horizontal shell and one vertical shell. So you would get a solid bottom layer, and a solid top layer, and 1 perimeter “wall” in which the gap between the edge of the walls is filled with your infill of choice.

When printing simple objects, that do not have lots of vertical angles, this is often an acceptable setting to reduce printing time, and increase printing speed. However, when printing a complex object like a funnel, you run into a difficult problem. Since each layer is set “back” slightly from the other to form the slope of the piece, with one vertical shell, you only get one point for each layer to bond to. Which means that if your printer has a half second hiccup, or your piece has too steep of an angle, there will be a hole. 

The solution is to add more vertical shells then. Because now, the interface of the two layers isn’t one outer wall offset from the outer wall below it, but instead 2 or 3. So far, I’ve found 3 shells to be the magic number for forming waterproof containers.

However, there is another complicating factor. Layer height.

If you haven’t noticed by now, there’s actually some nice overlap with calculus in this whole thing. At least a few people might be having flashbacks to Riemann Sums. Layer height has an immediate and noticeable impact on the quality of prints such as these. When I initially printed the tiny funnel, I printed it at .2 MM height I used with the flask.

The layers didn’t work. It’s such a small piece that the printer can only lay down 1 shell, with each layer barely touching the other. The solution then was to go down to .1 MM to improve the print quality. At .1MM the printer could put down multiple shells, and maintain the slope of the piece without issue.

On the other hand, the larger funnel? .4 MM. I decided to take a risk and it worked out well. At .4 MM the funnel prints quickly, and works well. It’s completely watertight.

So, to keep it simple. When setting up your prints in slic3r, think about the geometry of the piece you are making.

The best pieces are going to utilize a layer height and shell requirement that optimizes printing speed while still maintaining the integrity of the piece. Take some time while setting things up to look at how the piece is layed out. When slic3r completes, spend a few minutes checking out the preview in Repetier.

The last thing you want to see is a preview where it looks like single strands of filament have been carefully stacked on each other while barely touching. Those pieces rarely come out well.

Happy Printing in 2015!

-Meds

AI Research and Transhumanism

I hope everyone is having as relaxing of a Christmas day as I am. I have happened to have made a few friends down at my parents place.

A Confused Bird

Anyways, as we enter the new year, I wanted to post something by one of my favorite authors, Jaron Lanier. This piece, technically part of a larger discussion/debate at the always fantastic edge.org is worth the time it will take you to read.

Lanier himself is basically an OG of “future technologies”, having been one of the major pioneers behind the first wave of virtual reality and a respected researcher and programmer.

http://edge.org/conversation/the-myth-of-ai

Lanier also wrote a fantastic piece, now a bit dated, about transhumanism:

http://edge.org/conversation/one-half-a-manifesto