Category Archives: Personal Fabrication

3D Printed Cornea -Yes, Please!

Speaking of 3D printing for biomedical uses…researchers at Newcastle University report this summer on a promising technique for 3D printing of a replacement cornea [1]!

The technique creates a digital model of the cornea, in this case by optical scanning to create a 3D mesh representing the precise geometry of the cornea surface. This process is essentially creating an elevation map of the cornea.  The STL file was processed with slicer software to generate G-Code—just like personal 3D printing.

A “bio ink” was created which contained cultured structural cells from human cornea tissue. This was printed on a surface to create the artificial cornea.  The result was incubated to keep the cells alive.

The proof of concept study created promising tissue, though there is a lot of work to do before a viable replacement cornea can be created.

This development is of more than passing interest to me personally, as I will need cornea replacements in the coming decades.  Cornea transplants have been getting better and better, but there are only so many donors.  I’m really, really excited at the possibility of an unlimited supply of custom-built corneas!

  1. Abigail Isaacson, Stephen Swioklo, and Che J. Connon, 3D bioprinting of a corneal stroma equivalent. Experimental Eye Research, 173:188-193, 8// 2018.

3D Printed Objects ‘Connect to Wifi’

Researchers at University of Washington report some interesting work creating simple 3D printed objects that “connect” to wifi without complex electronics [1]. The objects can be used a sensor or input device.

The basic idea is that this technology can be low-cost, ubiquitous, and customized. While this system isn’t quite “without electronics” [2], the objects are simple enough to be fabricated with a 3D printer.  The fancy stuff is in a mobile device and the wireless network—which is assumed to be ubiquitous infrastructure.

The researchers made several examples, including an anemometer, a flow meter (water wheel), and a spring scale.  They also created input devices, a push button, a slider, and a dial knob.  These examples are building blocks for user interaction and for environmental or industrial sensing.

The idea is to use radio back scatter as a simple signaling device. Basically, an antenna is embedded in the printed object, with a switch that changes the reflectivity of the antenna. The 3D objects trigger the switch using clockwork or other mechanical action (e.g., a push button or turbine).  This mechanism can represent a (low bit rate) signal as a series of modulated reflections.

The signal is detected by processing the reception from a wifi or other radio receiver. Filtering out the high frequency signals will detect the low frequency data from the sensor.  This can be done with a mobile device such as a phone of tablet.

The coolest part is the 3D printed clockwork mechanisms used to modulate the transmission. Gears! Springs! Buttons!

The technical paper has details about how well it works, as well as interesting examinations of the interference of human movement (which modulates back scatter).  In order to use more than one such device, the “channel” can be frequency multiplexed by printing devices with different gear ratios!  That’s kind of cool.

  1. Vikram Iyer, Justin Chan, and Shyamnath Gollakota, 3D printing wireless connected objects. ACM Transactions on Graphics, 36 (6):1-13, 2017.
  2. Jennifer Langston, In first, 3-D printed objects connect to WiFi without electronics in UW News. 2017.


Make Smthng week?

This is MAKE SMTHNG Week, promoted by Greenpeace among others.  This idea combines interest in reducing wasteful consumption and empowerment by Making, and ties it to countering the commercial maelstrom of the holiday shopping season.

In short, they advocate, ‘instead of going shopping, make and do it ourselves.’

I certainly appreciate the value of reducing consumption, and, where it makes sense, reusing and sharing.  And I’m a long time advocate for Making and personal fabrication.  But this project leaves me uneasy for several reasons.

For one thing, while Making is certainly empowering, it isn’t necessarily ecologically sustainable.  Some makers are into reuse and upcycling, but many use non-recycled materials to build what amount to toys. In fact, the whole idea of Making is to create whatever you want, not to reduce consumption.

In short, upcycling is a subset of Making, but you don’t have to be interested in reusing stuff to be a Maker.  For that matter, you don’t have to be a Maker to reduce waste and consumption.

Even more troubling is my observation that many local makers try to make a living from their own DIY creativity.  That is, local cratspeople sell their creations for income. These artisans rely on holiday sales are critical for their livelihood.

So, ‘making smthng’ instead of buying from local makers can be really bad for your local makers, for your local economy, and for the whole planet.

To my mind, “buy smthng local’ is more important that ‘make smthng yourself’.  Not that you can’t do both – though that probably uses more resources.

All that said, I certainly encourage people to learn about reuse, sharing, and recycling. The more you understand where stuff comes from and what your choices are, the better citizen you will be.

By the way, I do like their web page, which invites you to “Start creating…[drag the elements around]”.  That’s kind of cool, though utterly and totally useless and wasteful (because using the internet on a computer or mobile device is horribly, horribly resource intensive.)

(File this under “Bah! Humbug!”)

  1. Greenpeace. MAKE SMTHNG Week 2017,


Robogami: “Democratizing” Robot Building?

In a recent paper, Cynthia Sung and colleagues at MIT describe their automated design system, which addresses a “long-held goal in the robotics field has been to see our technologies enter the hands of the everyman [sic].” [1]

Well, I don’t know about that. Every nerd, maybe.

The idea is a high level design system that generates simple “fold up” robotic vehicles, suitable for fabrication with ubiquitous laser cutters and other shop tools. The computer system helps the designer create the “geometry”, the 3D shape of the vehicle, and the “gait”, how it moves. The system shows the results in a simulator, so the designer can rapidly iterate. The prototype is then sent to a printer, and snapped together with appropriate motors and wires.

One of the main challenges in robot design is the inter- dependence of the geometry and motion.


As the paper makes clear, this idea was influenced by a number of current trends which I’m sure are bouncing around MIT CSAIL and everywhere esle: computational aided iterative design, rapid prototyping with personal fabrication, and, of course, Origami <<link to post>>.

The system also reports performance metrics (e.g, speed of locomotion), and helps optimize the design.

Of course, this isn’t really a general purpose robot design system. Aside from the fact that the hard part in any design is figuring out what to design (and diving into iterative prototyping often distracts from careful thought and research), useful robots have sensors and manipulators, as well as machine learning or domain knowledge or both, which is not part of this design.

This system is really only about the body and the movement: essentially, the basic shell of the robot.  Important, but really only the foundation of a working, useful robot.

“The system enables users to explore the space of geometries and gaits”

It’s cool, but not the whole story.

And, let us not forget, the appearance and sociability of the robot is increasingly important. These cute little robogamis look like toys, and are little more use than a toy. These are certainly not social robots!

Now, if you sold this as a “toy factory”, perhaps with some stickers and funny voices, you’d have a bang up product. Don’t give Suzie a doll, give her a machine to make as many dolls as she wants!  And the dolls move and talk!

Now that would be cool!

  1. Adriana Schulz, Cynthia Sung, Andrew Spielberg, Wei Zhao, Robin Cheng, Eitan Grinspun, Daniela Rus, and Wojciech Matusik, Interactive robogami: An end-to-end system for design of robots with ground locomotion. The International Journal of Robotics Research:0278364917723465, 2017.


Robot Wednesday

Barcelona Fab Market for Open Source Design

Cat Johnson writes about the “Fab Market”, which is an initiative associated with the world-renowned Barcelona Fab Lab. The basic idea is an online shop that sells products to be made at a local Fab Lab. The designs are created by designers anywhere in the world, and are supposed to be open source. The Barcelona group curates the collection, conducting quality control and overseeing the system.

The business model appears to be that you will pay to obtain either the plans (which are supposedly “open source”), or the parts ready to assemble (DIY), or a fully assembled product. The fabrication and assembly are done at your local Fab Lab—supporting the local economy and reducing transport costs. Some of the revenue goes to the local Fab Lab, some to the workers, and some to the designer.

This effort is part of a larger vision of “Fab Cities, which imagines more self sufficient cities that fabricate a significant portion of their goods locally. Even before anything like that is achieved, this idea may be an opportunity for designers and for local workers.

Johnson summarizes the potential of the Fab Market:

Some of the benefits of the Fab Market system are:

  • Engaging and empowering people in the manufacturing process
  • Spreading the open-source ethos of sharing and collaboration
  • Reducing environmental impact of creating and transporting goods
  • Increasing transparency in the supply chain
  • Reducing the time and costs of production
  • Giving talented designers a platform for showcasing and sharing their products
  • Connecting a global community of makers

The big picture for Fab Market is to create a distributed economy based on good design and quality products that are made to last.

This effort joins existing “open source hardware” concepts, all of which are creating a global collection of artifacts for gardening, office furniture, clothing, plastic recycling and housing and homesteading.

In the same vein as Fab Market, Obrary is a global library of open source designs, available for free download (under creative commons).

Looking at Obrary back in 2014, I commented:

Suggested Feature:  One thing I would really like in a service like this would be some way to find local workers who will build. For example, if I need beehives, and I find a design I like at Obrary, and I want to buy one or more.  It would be nice to have a way to find one or more people in my town with the skills and tools, and pay them to do the build. In this case, there might reasonably be a “suggest donation” back to the designers, but most of the money would be in my local economy, supporting families where I live.

“This can be done informally, and I’m sure it will.  But is there a role for something like Obrary in this process?  And if so, how should it be done?”  (Posted September 5, 2014)

Voila! Barcelona is trying to do exactly this with their Fab Market. How can I disagree with something that was my own idea! 🙂

The obvious next step is to integrate and cross-fertilize these “open source hardware” collections. For example, it should be easy to order up anything in Obrary, and the collection in Fab Market should be accessible via Obrary. Ditto for Aker, OpenDesk, The Global Village Construction Kit, and so on.

I think this kind of interoperation should be doable, with a little bit of imagination to make Fab Market, Obrary, and so on part of an open network of catalogs. (Talk to your local librarian about open standards for catalogs….)

Such a development will also make it possible for others to join in with yet other curated collections of open source hardware, possibly with different business models. For example, garden equipment might be discounted for people who are certified participants in local food exchanges.

Note that Fab Market and the other sites are effectively offering their services as expert curators. This means that a consumer can have several options among curators, to get different perspectives. Opening up the curating process will make it possible for bottom up and peer-to-peer “curation”, so anyone can pull together an inventory of designs, and offer them to the global market of local makers.  It is also an opportunity for local makers and builders to advertise their expertise (by referring to the global catalog).

This is an interesting developments. We’ll see what happens in the future.

  1. Cat Johnson, Here’s How Fab Market is Creating a Sustainable Marketplace. Sharable.January 17 2017,


Hacking 3D Printing

I’ve written about our great age of making which has led in the emergence of community based maker spaces, and revolutions in product development and manufacturing.

One of the key technologies is additive manufacturing, most famously, inexpensive 3D printing. At the heart of 3D printing and other digital fabrication is the “executable design”, machine code files which not only describe the object, but specify how to make the object. This is one of the most exciting things about digital fabrication, because these files mean that we can do everything you can do with any digital content: publish, share (or sell) over the network, copy, and modify designs.

Unfortunately, just as you can upload, search, and download digital designs (e.g., Thingiverse), you can also hack them. This is a serious issue, especially for a business relying on digital fabrication, and for anyone building critical or dangerous machines from digitally specified parts.

The security issues are pretty simple, basically the same as for any other data, though the possible mischief is much more complicated, because the parts are physical objects in the real word. It is correspondingly difficult to detect hacking, because slight changes to any of a dozen files might create a fatal flaw that is not apparent until the parts are assembled and the machine operated.

Researchers at Ben-Gurion Univiersity of the Negev have published a very clear demonstration of this challenge [1]. The walk through a complete attack that includes hacking into the system with the design files for a quadcopter, stealing the files, monkeying with the design in ways that are not easy to see, and replacing the good file with the doctored one. The unwitting user, prints out the parts and assembles the copter—which promptly crashes when a rotor fails.

It is important to note that none of these steps is especially clever or technically deep. Hacking into the system is, unfortunately, widely known and common. Obviously, the hacker needs to know a bit about digital design to do the sabotage, but the actual method is simple as pie. Worse, the hacked file can be used as many times as wanted, so the hack might propagate quickly.

The whole point is just how straightforward and simple the attack is, and to give a very visible and memorable image of the consequences.

With the growth of additive manufacturing worldwide, we believe the ability to conduct malicious sabotage of these systems will attract the attention of many adversaries, ranging from criminal gangs to state actors, who will aim either for profit or for geopolitical power

Another point to comment on is that this particular attack didn’t even touch the control software and logic, which are equally vulnerable in many cases.  Yoiks! And don’t forget the other stuff, such as the controller, the sensors, and the data streaming software used by the copter—any and all of which could be hacked just as easily.

In addition, the BGUN hack was designed to illustrate the fact that it is very difficult for humans to visually verify these design files. The data is pretty much beyond human understanding, and the part looked OK, even though it had been modified to have a fatal flaw.

The unfortunate implication is that it is difficult to trust design data in general, even without deliberate hacking, how can you tell if this part is a good design or not? I can see a need for provenance, to try to establish a chain of trust for all the parts of your system.

  1. Sofia Belikovetsky, Mark Yampolskiy, Jinghui Toh, and Yuval Elovici, dr0wned – Cyber-Physical Attack with Additive Manufacturing. Ben Gurion Univiersity of hte Negev, 2016.


The Mighty Megaprocessor

OK, this is cool! I can’t say that I want one—but I would love to visit it to admire the shear “wondrous insanity” of this guy.

As Steven Cass puts it, a monument to our kind of crazy

Sensei James Newman, a man with time and space to burn, has built a fully functioning 16-bit “microprocessor”, blown up to macroscopic scale!

The Megaprocessor.

Motivated by curiosity, Newman built all the components, to implement a simple instruction set, registers, and memory.  The resulting beast is 10m long and 2m tall, with 40,000 transistors and even more LEDs. Evidently he also wrote an assembler and simulator, as well. Phew!

Giants walk amongst us!

The resulting processor is far less capable than the computer in a smart watch, yet consuming much more power and taking up much more space!

Newton plans to prepare some tutorial walk throughs, to explain how everything works, and how to build it from the ground up. Very cool!

One thing that is interesting is that this is project is that it is a sort of walk-in, whole body computer—unlike tiny, sealed chips, you get a really visceral grasp of how things work and what is happening.

But this is far, far from “invisible” computing, and certainly not wearable! Actually, it wears you!

And, by the way, there is no touch screen!

The Megacomputer is to appear in the Centre for Computing History at Cambridge.

  1. Stephen Cass, The megaprocessor. IEEE Spectrum, 53 (10):19-20, 2016.