Interlock is a non-profit organization that provides space for its members and the local community to develop and share their interests in science, technology, art, and culture.
I’ve been working on a telepresence robot on and off for some time. One thing I was held up on was getting the main structure built. I had done a design in Sketch-Up, but had no idea how to actually get it made for real. It turns out there are several options for getting acrylic designs produced. In this case, I chose water-jet because it leaves a nice edge on the finished parts. I wrote up a pretty detailed set of instructions for building the robot structure on the project wiki. In those, I talk about the production of the parts and assembly process. It details how I used Weld-On #3 to bond the parts. This works very well for acrylic since it sets up fast, creates a fast bond and is relatively easy to work with.
Giftmas origami balloons made out of wrapping paper.
One way I kept on an even keel during the recent holiday season was by taking every opportunity I could to practice making these origami cubical “balloons” using scraps of wrapping paper. I made in excess of a dozen, and that was the high point of my recent kick to practice enough to be able to do this pattern from memory.
From a maker-theory perspective, even with the digital revolution and the move to e-texts to replace things, like books, that have traditionally used paper, paper as a material is still ubiquitous and cheap. Its ready availability means that one can cultivate the maker state of mind just about any where–I started out on this recent origami journey after lunch one day a couple of months ago, using the coated-paper basket liner at a burrito place.
Paper fast-food tray liners and place mats do pretty well in a pinch, and making something then and there is a great way to entertain a youngster or to open a discussion with an indulgent friend, co-worker, or even a stranger, about the fun to be had as a hacker and maker.
Amongst different types of paper, paper sold as “origami paper” can be a little more hard to find and more expensive. I also try to resist that tendency projects have to lead off with “first, go out and buy something”. So I set out to figure out a way consistently to convert randomly-shaped scraps of paper into squares suitable for use with traditional origami patterns.
More recently, at my last turn on door duty for Interlock’s “Do Night” I worked on expanding my repertoire a little bit, learning how to make these open-toppedboxes. Also, Reggie was a pretty ggod sport about taking some instruction from me about how to fold up his own balloon made from wrapping paper I pushed on him.
So far, I’m not that enthused about making little animals. Also, I had my paper airplane phase as a kid, so that doesn’t hold a lot of appeal for me at the moment. Mostly, pure geometry, as in the balloon-cubes, and potentially useful knick-knacks, like the candy box, are what I’ve been after. With the holidays gone, my interest may fade for a bit. We’ll see.
I thought I’d do a primer about NFC since Samsung’s Galaxy Nexus is getting a lot of press about it. You may have heard of Google Wallet or how NFC is going to be built into smart phones in the future. Maybe you haven’t thought about how it works or how to hack it. As a side[side(side)] project I’ve been working on NFC research with (as always for me) a specific focus on the security perspectives. This is an overview of NFC to maybe peak your interest.
Define:NFC
Near Field Communication is a way to transmit information between intelligent devices. I know you’re already thinking Bluetooth but wait. NFC has a limitation that says in its spec that it can’t be more than .2m away from its partner during communication. It may be a bit more depending on the implementation but the thing to remember here is that the protocol itself is what limits the distance, not just the hardware. (Quit pointing that gigantic antenna at my pocket right now!) It transmits on the HF band 13.56MHz, a frequency already used by some RFID chips and fun devices like the Proxmark 3.
Modes
Here’s what’s different about NFC: There are three different modes.
Reader/Writer: Commonly used in smart posters or smart stickers. Think QR code but subtle.
Peer to Peer: Data is exchanged back and forth between devices; securely exchange credit cards, give your friend your home WIFI settings, or exchange business cards.
Card Emulation: A device acts like a contactless smart card. What if you could use your phone as a bus pass instead of keeping that flimsy magstripe pass in your pocket?
NFC != RFID
Lets take care of that up front. NFC sounds a lot like RFID (they share the whole RF thing) and it seems to get stored in people’s heads that way because NFC has the card emulation mode where it emulates at “tag” or an RFID chip. RFID isn’t usually much more than a tag blindly broadcasting data hoping a receiver picks it up. Passive tags (or little antennas without a power source) sit and wait for an RFID reader to come by to energize them. They get all excited and tell the reader everything they know. Imagine a dog just waiting at the door for it’s owner to come home. The active RFID tags have a battery in them that constantly broadcasts itself to anyone that will listen. Kind of like that annoying friend you have that tells you everything about their life even though you never asked. NFC on the other hand is like an intelligent college student. She can have an intimate conversation with you, she can make a presentation in front of a class, but she can still get drunk and act stupid if that’s what everyone else is doing at the party.
NFC is not a new technology
We’ve seen them in European phones since 2003 or 4 and they’ve been hacked on for just as long. The folks at the Chaos Computer Club have been hacking on NFC since it’s original inception; when manufacturers like Nokia started installing it into their feature phones, AKA dumb phones. It never made it across the water – some may say due to some FCC regulations on the 13.56 frequency but I’ll leave that topic to the Ham guys.
Security
If you haven’t already, you should put on your tin foil hat now. NFC is a way for corporations to take over our bodies, man! Well…most likely not. But you’re already thinking about the security problems as soon as I wrote “credit card.” I’m going to save this whole discussion for another day but the tl;dr version is that NFC has been designed with security in mind but a lot is left up to the developer to implement securely. We all know how well that works especially for mobile app developers so I’m sure everything is going to be fine, right? Maybe next time I’ll tell you about the butt sniffing attack. No seriously.
Android and The Galaxy Nexus
How is Android implementing NFC in the Galaxy Nexus? Here’s an example of a peer to peer mode connection: When you put a Galaxy Nexus next to another Galaxy Nexus, the phone will make an NFC connection as long as both phones are unlocked. If the app that you have open supports NFC (i.e. Google Maps) it will allow you to communicate data from your app to the other device. Some examples of this are sharing contact information, location data, websites, etc but apparently it’s going to be used for games or whatever developers can think of.
The Reader/Writer mode will allow you to take an NFC tag and shove it next to the phone. Depending on the data stored on the card, it will open an appropriate app to view the content. In the case of an NFC tag that is contains a URL, it will automatically go to that page. Ask me about some of the NFC tags I’ve made at a 2600 meeting sometime.
Last Thursday’s Do night, JustBill brought in his HF rig to try out on our club antennas. Bill is an expert user on several digital communications modes including PSK31. PSK31 or “Phase Shift Keying, 31 Baud” is a digital radio modulation mode, used primarily in the amateur radio field to conduct real-time keyboard-to-keyboard informal text chat between amateur radio operators. After we got his rig set up and interfaced to Ham Radio Deluxe running on the club computer, we started a session on 40 meters and keyboard chatted with a guy in Spain. We also chatted with a Ham in Wisconsin and another in Alabama. We heard a Russian station but not quite enough signal to get to him with 50 watts. Here’s a link to a wiki on PSK31:
JustBill at the controls….with aliens supervising
We also got an old Radio Shack HTX-202 operating APRS (Automatic Packet Reporting System) with UI-View32 (an ancient client software for radio packet hosting) and the ProComm TNC to communicate to the radio. K2HAX is on the map! APRS is an important tool for position reporting, remote telemetry, text messaging anyone anyplace, and local coordination of emergency training events. For a cool view of current APRS activity around K2HAX, go here.
We’ve got a 3d printer! It’s still a bit “in progress” as far as building and tuning it goes, but anybody interested in small-scale hobby-level 3d printing should stop in to ogle as our new eMakerHuxley RepRap prints out whistles and gadgets and geegaws all night long.
The build was pretty involved, but with a group of four folks we managed to get the majority of the work done in one long Sunday, a time-lapse of which follows:
That resulted in the following structure, which just needed to have its nozzle and build platform installed (and quite a bit of wiring).
With surprisingly little calibration and tinkering, we finally got our first fully printed part last Friday, the semi-traditional whistle model. The quality is really good already, and will get a bit better once we tweak some settings and really get the machine purring.
I think the nozzle is clogged now, unfortunately. So my goal tonight is to clear that out and get plastic extruding again, and then try to print out the interlock logo, which you can see above, extruded from a DXF file in openSCAD. Come visit, and bring a model you might want to print! There’s plenty of inspiration and/or finished “things” on Thingiverse if you don’t know where to start, and we’ll have a class soon on how to go from and idea to a 3d print… so stay tuned!
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