Wednesday, January 30, 2008

CandyFab: The Revolution will be Caramelized

Here's a PDF presentation about the CandyFab, an unusual approach to a hobbyist fabber. These guys decided they could relax their spatial resolution in favor of large volume and cheap fabbing materials. Their fabbing material of choice is sugar, much cheaper than the plastics used by RepRap. Some of the things they make are considerably larger than can be made with RepRap. Here's a Flickr photo set.

In September the CandyFabbers came up with a better hot air nozzle that gives them considerably improved spatial resolution, with volume pixels of about 1/16 inch instead of 1/5 inch.

Some MIT folks have built a fabber that makes stuff out of pasta dough.

Tuesday, January 29, 2008

How does one get started?

How does one start to build one's own fabber? RepRap and Fab@Home both offer instructions. There is of course the caveat that the technology is new and experimental and bleeding-edge, so it's not a shrink-wrapped thing where you simply tear open the packaging and start using it. My goal in this posting is mostly to decide whether it makes sense for me to start work on a fabber. My early conclusion is that I'd like the field to mature a little bit more, but it might be fun to tinker with just the 3-axis motion part (check out the video), probably using this microcontroller board.

The RepRap folks have a page about constructing their version 1.0 fabber, called "Darwin". They recommend that you join the RepRap Research Foundation, which supports new fabber builders, and you can purchase parts from their on-line store.

Fab@Home has a Getting Started page with links to their catalog and the list of materials that you can fab with. A pre-assembled Fab@Home fabber will set you back about $3600 plus shipping, currently with a 6-to-8 week lead time, so I guess people are buying them. The Fab@Home is an impressive thing, and good looking.

Hobbyist fabbers today look the way Linux did in 1993. In five or ten years fabbers will be much more common and much more polished, but the people tinkering today will have 99% of the fun. Linux in 1993 was not at all user friendly, everything needed to be hand-tweaked, and you needed to understand a lot of it to use any of it, and the same was true with cars in 1910, and with fabbers now.

Brilliant RepRap video (thanks to Emeka Okafor)

I am deeply indebted to Emeka Okafor, author of the Timbuktu Chronicles blog and director for the TEDGlobal 2007 conference in Tanzania, for stumbling across this brilliant Poptech video of Professor Adrian Bowyer, the inventor of the RepRap fabber. I would also like to thank Mr. Okafor for giving attribution to my nanotechnology blog, and call attention to his postings on technologies that can help Africa and other developing regions. There is an Emeka Okafor who plays basketball, I'm not sure if it's the same guy.

Bowyer talks about the economics behind the project, particularly its ability to empower communities that are now economically depressed. There is some yummy game-theory stuff in the paper linked here that does not get mentioned in the video, check it out. He also talks about using polylactic acid (wikipedia) as a printing material for the RepRap. This is significant because you can make PLA from starchy vegetables like potatoes and corn, and when you're finished using your PLA object, you can compost it to help grow next year's crop of starchy vegetables. You can have a closed-loop local manufacturing economy that doesn't require trucks or trains or ships to move products around. In fact there are several materials under consideration, and thought has been given to printing a single product from multiple materials. The Fab@Home folks also have an impressive list of materials that can be fabbed, including chocolate.

I got curious about PLA and did a little googling. In a RepRap forum there is a discussion of just how easy it is to turn starchy vegetables into PLA. From the sound of it, it is non-trivial and demands that the person attempting it be quite knowledgeable. One person compares "home PLA production today to home biodesiel production 20 years ago, when it was arcane, a little dangerous, and rare, but theoretically possible" and notes that for many people it will simply not be economical compared to mail-ordering some PLA. I found a place that sells utensils, plates, and cups made from PLA. NatureWorks appears to be a source for PLA in ready-to-work form.

3D printer in a knick-knack store

Make Magazine has a note about an Umbra concept store in Toronto which now has a 3D printer (some people also call them "fabbers"). The store can use it to fabricate novel items, and the store chain designers visit the store to create and fabricate designs while chatting with customers about the process. The little white widgets to the left of the printer are some of its products.

I'm interested in 3D printers, but I haven't dedicated the time to build my own, as some people have started to do. It's intriguing to imagine what 3D printers might accomplish in combination with automated design techniques such as genetic algorithms (here are some more GA links).

At the present time, 3D printers are the closest things to real nanofactories, and they present limited versions of many of the same challenges that nanofactories will bring, such as copyright issues and the bumpy ride toward a post-scarcity economy.

Monday, January 28, 2008

Starting a fabber blog

Lately I've been thinking and posting a bit about fabbers (also called 3D printers), primarily on my nanotechnology blog. I think the topic (and my growing interest in it) is rich enough to deserve its own blog. I am particularly interested in affordable hobbyist fabber projects, something I might be able to fool around with myself.

The fabber idea is pretty simple. Take a hot glue gun and three stepper motors. Use the stepper motors under computer control (with appropriate mechanics) to position the hot glue gun at a specific XYZ point, and deposit a drop of hot glue. The glue cools and you move to the next XYZ point. Use this arrangement to draw a glue pattern on a horizontal surface, then move up a little bit and draw the next layer, and then the next. Soon you've got a 3D object of almost any shape you wish. A few of the details can vary -- it's not really glue, it's typically a polymer like polylactic acid -- but that's the basic idea.

There are professional and industrial fabbers with prices starting at about $50,000. But more interestingly, there are hobbyist projects to build much more affordable fabbers. The two currently prominent hobbyist efforts are the RepRap project (wikipedia entry) started by Adrian Bowyer at the University of Bath in the UK and the Fab@Home project started by Hod Lipson at Cornell. There are others but these two have the highest visibility and, as far as I can tell, the largest numbers of participants.

The Fab@Home fabber looks more polished than the RepRap, but I find the RepRap more interesting. Partly because it's more affordable (a getting-starting price somewhere around $400 versus $2300) but also because Bowyer is more committed to an open-source approach and is more interested in the implications of that approach. He very intentionally designed a machine that could fabricate most of its own parts and could therefore mostly copy itself. If the machine becomes popular, its price will quickly drop (building one today might cost a good deal more than $400 and a very large investment of tinkering time) to roughly the price of the few non-copyable parts and the raw plastic for the rest.

Sunday, January 27, 2008

Videos and links, RepRap and Fab@Home

Since I've been writing a lot about fabbers lately, I've decided to start a fabber blog and start migrating my fabber postings over to it, starting with this one. Fabbers are only peripherally related to advanced nanotechnology (the economics look similar) and I'd like the fabber blog to go into a level of detail that's not appropriate here.

As far as economic similarities, a fabber looks a lot like a crude nanofactory, and raises many of the same societal concerns but in a smaller, safer way. One of the popular speculations about mature nanotechnology goes like this: (1) sufficiently advanced nanofactories will be able to make almost any desired product from materials found in nature, so (2) the price of physical goods drops to nearly zero, and then (3) money ceases to exist and we all live in a post-scarcity society free of poverty, disease, and war.

It's an appealing simple notion, probably too simple. Even when the necessities of life are available essentially for free, humans always envy other humans and there will still be a premium to pay for things beyond the survival level. Economic demand will exist as long as we're still human, and money will too. Besides, physical goods aren't the only things we spend money on. I can imagine a robot bus driver at some future time, but a robot doctor seems a long way off, and it's hard to imagine the board of directors that will appoint the first robot CEO.

Tuesday, January 01, 2008

Xilinx Spartan 3 FPGA eval board

I was thinking I wanted to do something with the ARM91SAM7 eval board and a Xilinx FPGA, and I discovered that Xilinx also sells a eval board for their Spartan-3 FPGAs for $150. Here's the user guide (PDF). Big surprise, it's available at Digikey.

The Spartan-3 series has hardware multipliers, blocks of RAM, and "distributed RAM bits" which you can spread around your design as needed. Pretty sweet. As I mentioned in an earlier posting, there are readily available HDL tools for FPGA design on a Linux platform. Hardware design shouldn't necessitate the indignities of Windows.

Here is a ridiculously affordable SAM7 board that I need to investigate. It lacks RS-232 level converters, and you need to kludge the JTAG stuff (probably drive it with a parallel port somehow or other). Also interesting are these two open-source simulators for the ARM7 architecture.

The idea would be to use the SAM7 eval board to program the FPGA on the Spartan-3 eval board. FPGA programs are pretty large, so maybe this should be done by feeding the bits through the USB cable. Then you have some GPIO bits on the SAM7 connect to IO pins on the FPGA, and other IO pins on the FPGA to the outside world.

Some years ago, there was a guy who got his hands on some prototyping hardware of this sort (PowerPC based, I think I recall) and he set up a paid-subscription website where subscribers could submit compiled code and run it on his hardware. The cost of a subscription was small compared to the price of buying one's own hardware. According to EE Times Asia, Hitachi was doing the same thing in 2002.
Hitachi Semiconductor America Inc. is trying to move remote engineering to the next level by letting customers tinker with microcontroller hardware and software tools via a Web browser.

Working with DevelopOnline, Hitachi has set up several remote development stations for its H8 microcontroller family. For a fee, engineers can access these remote engineering laboratories from a PC at any time. Hitachi launched the service with its H8/3664 microcontroller device and plans to expand the program during the next several months to include other members of the H8 line and the company's SuperH devices.
One could make two of these gadgets and connect one to an Apache box to set up a remote development website like this. The second gadget is used to tweak/observe GPIO pins, interact with serial debug, etc. There would need to be some mechanism for allocating time fairly among multiple subscribers. The website would want lots of example code (or pointers to code findable on the web) for people to get started.