Friday, September 28, 2012

Fun with the Raspberry Pi

If you've heard about the Raspberry Pi, (wikipedia, a $35 single-board Linux computer, you probably won't learn much new here. The main point of this post is that I got mine to boot, so I do have one or two small bits of advice to pass on to those working toward that goal. First, photographic evidence (veracity: if I were faking it I wouldn't put a big reflected flash in the middle of the screen).

Here's the board booting. Booting (and everything else) is a little slower on the Raspberry Pi than you're probably accustomed to. But then, hey, it's $35, and you can stuff it into whatever piece of hardware you're building and have full-blown Linux with X Windows. So live with it.

My experience has been that at least in the near future, it's not really $35. Here's what happens: the Raspberry Pi folks build a bunch of boards and sell them for $35, but they get picked up by people who want to resell them, so you end up getting yours on eBay for somewhere in the $55 to $70 range. Eventually this mischief will end and the price will stabilize.

 Photographic evidence number two: the board has booted into X Windows. This is using the recommended-for-beginners Debian-based distribution,, which unpacks into 2012-09-18-wheezy-raspbian.img, and obviously the date in that name will be updated periodically.

So here are the tips for fellow beginners:
  • First, remember this board is designed for complete novices, and even, heaven help us, artists. Do not despair, you ARE smart enough to get it working.
  • The Raspberry Pi folks warn you away from micro-SD cards, but the one I'm using works fine.
  • You may find that your keyboard is mapped in a funny way. My (@) key and (") key were swapped, and the (#) key was mapped to a British pound sign (£). One solution to this appears here. Mine was to create the file /home/pi/.xsessionrc which contained this line:
setkbmap us -option grp:ctrl_shift_toggle

A better approach to the keyboard issue is one of the options in raspi-config (the first thing that appears on your screen after all those boot messages finish). Look for "keyboard configuration" and select the canonical U.S. keyboard choices.

Everything else seems to be working, but I haven't tried to do much yet. I have no idea how to talk to GPIOs or other peripherals yet, but I've done that with other Linux boards and expect that my past experience will get me there pretty painlessly. That, and there is a HUGE community for this thing.

Looking forward to checking out Adafruit's WebIDE when time permits. The development system runs as a web server on the board, and you develop in the browser on your laptop over a network connection.

And now for your viewing pleasure, assorted Raspberry Pi pr0n:

Thursday, September 27, 2012

Cool new 3D printers

I don't want to fall into the habit of only blogging once per year about MakerFaire. So this post is actually about a crop of cool new 3D printers, and I'll probably see a few of them there, but it's not about MakerFaire proper. These all fall in the $1500 to $2500 price range.

First up is Makerbot's Replicator 2. There is some controversy around this one, because it's a mix of open source technology under the GPL, and some new technology that's very likely not open source, which allows for a much higher print quality. The open source 3D printer advocates are concerned that it violates the GNU General Public License. The open source technology is primarily the work of Adrian Bowyer who started the RepRap project, and he's given (unenthusiastic) permission to Makerbot to use it.

One of the RepRap enthusiasts is my friend Jeff, who will have a table at MakerFaire this year to show off the printer that has occupied two or three years of his nights and weekends. I like Jeff and I think he'll probably not be too happy with Makerbot's decision to include closed-source technology. But the step up in quality for the price is pretty appealing for a non-GPL-purist like myself. I don't worry about running GPL software on closed-source laptops, after all.

Second is the FORM1 from some Media Lab folks. I don't know much about these folks or their history, but the Media Lab has been at the cutting edge of high-end 3D printing for a couple of decades now, so they've probably got something pretty interesting. I think their raw material is a liquid rather than the long plastic spaghetti sticks used by most other affordable machines (based on one photo on their Kickstarter page). This is the most expensive of the lot, price currently listing as $2500.

Third is the UP!Plus from 3D Printing Systems. Their output doesn't look as nice as the Replicator 2 or the FORM1, but they are at the more affordable end.

What's cool about all these printers and some other new ones is that the user friendliness and quality of output are improving rapidly in recent years. Before long, these things will be popping up in homes, dorm rooms, high schools, and the local mall.

Makerfaire NYC 2012 is this weekend, and I'll be there to checkout 3D printers, microcontroller boards, art installations, and whatever else is around, and I'll blog about what I see.