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The first thing that I’m going to use it for is an interactive music player or generator for a friend’s art piece. It’s going to change what’s played based on how many people are in what parts of the room. I’m going to do this by counting the number of people who enter the room using infrared LED sensors, and then setting up sonar threshholds for people to be counted as they cross. To implement this I’ll use the sheevaplug, two arduinos, a bunch of range finders, and either a long cable connecting the two duinos or a couple of xbees.

I’m going to have four pairs of rangefinders on a post, each pair pointing in a different direction. If I see the distance from one rangefinder in the pair drop (call it A), then the other (call it B), I can guess that a person just walked in the direction A to B. I’ll decrement the count of people from A’s quadrant and increment it in B’s quadrant. The music will change depending on how many people are in the room, and how many are in each quadrant.

Why the sheevaplug? It’s powerful enough to generate sound and pipe it through a USB sound card.

The first step in this ordeal was to get FTDI working on the sheevaplug. It appears I wasn’t the only one with this idea. This is great news for me because the kernel I needed to get FTDI working was already compiled. I had some trouble at first, I’d see the kernel was being uncompressed and then it’d hang. As it turns out I forgot to run a few setenv commands. Oops. I was able to run those from the serial console and get going. Now the plug is running just fine.

My next step is to pick up a couple of motion sensors and see if I can get the people counter working. I expect to run into some problems with interference, so I’ll have to play around with the transmit timings. If it works with the two then we’ll see about getting funding. In any case I’m trying to get the costs down, those range finders are expensive!

This target market is pretty specific, I know, but I wrote a script to make searching for books at available at my local library more easy while browsing Goodreads. I’m starting to use Goodreads to track what I’m reading and also find suggestions from friends.

Connie Crosby linked via Twitter to a blog post on how to automatically search your local libraries while browsing Amazon. I don’t browse Amazon that often but it did get me thinking.

When I want to read a book I generally first check out the TPL’s downloadable section. It’s a little sparse for anything other than computer books. (Yes, I do read things other than computer books.) Anyhow, I’ve already gotten some use out of my script when only dead tree editions were available, and I imagine others will find the script handy too.

What it does is it searches the Toronto Public Library’s catalog for the 13 digit ISBN of any book that you visit on Goodreads. If it’s in the catalog, you can click a link that’ll pop up a list showing what branches it’s available at, and place a hold if you want.

This was made possible by the new beta website which is still a work in progress. Still, very cool features have been rolled out.

Known issue with the script: I couldn’t get the “place hold” button to select the right branch, no matter which “place hold” link you click it will ask you to select your branch.

Watch the 1.5 minute video below if you want a preview of what the script does.

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The idea was to provide an easily accessible translator for people on the ground. At the time the project started there was no Google Translate project that worked back and forth between for English and Haitian Creole. I think it was Chris that got a translator working based on moses after it’d been fed a corpus of every piece of Creole that he could get his hands on. The CCTO team’s job was to put together a web front end, and an API.

We were asked to write in python. There was no binding for the frontend, but Google had just made their Creole translator accessible. For testing purposes, we’re using their AJAX frontend. After a couple false starts with mod_python and Django, Brian and Kevin rewrote using the Twisted framework. It’s a little more obscure but it’s going to be easier to plug in other mediums like SMS.

We did in eight hours what a more organized team could’ve done in one. It’s hard to feel like I contributed anything other than two false starts and a bit of test code, but I’m still glad I went. I got to participate in creating what I think will be useful on the ground, even if I didn’t add much traction. At the very least I got to learn what it feels like to have a deliverable and a deadline but no spec.

You can see the notes by visting the site and clicking on the archives. Unfortunately I can’t do permalinks very readily, so I might export and clean it up later.

The last reason I didn’t post my notes here is due to my blog being in need of spring cleaning. I need to switch to a cleaner, less busy theme, so might pick one up from WooThemes. I’ll be taking another look at that later tonight, as well as merging my categories.

Since most of my readers are American, I’ll start off by linking to the MSNBC list of suggested aid organizations. Many groups in the list have Canadian counterparts too.

I tried to decide between Doctors Without Borders or Red Cross. It seems that they’re neck and neck in terms of their administrative cost, so I went with the Red Cross due to their shelter programs. I donated using their online donation box.

The Canadian government has pledged $5 million so far, as well as sent a DART team and put the HMCS Halifax on standby.

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I remember when Telus shut down thousands of websites to take down their union’s website. Serverloft might have just done the same. The Seattle Post-Intelligencer has an article on the takedown of the Yes Men site. I did find an article from straight.com which claims to have the original complaint. The IP address in the complaint there is the same one that ec-gc.ca is currently hosted on. Ole Tange is the contact for PiWeb listed in the IP address for that whois.

At first I was convinced that Serverloft did in fact pull the plug on PiWeb’s netblock. A slashdot comment gave me pause. After all, the message from Mr. Tange is on a website controlled by the Yes Men, and his contact details are publicly available. As of this writing, the PiWeb status page makes no mention of related downtown. Maybe the Yes Men took down their own site as a PR stunt. Here’s a paste from the disputed website.

Website suspended

Serverloft blocked the IP-range for this server because of the content of the client’s website and would only unblock the IP-range if we suspended the website. The website was used in a spoof by The Yes Men.

Serverloft blocked the IP-range without a warrant and without calling us and thus affecting servers hosting 4500 of our customers’ websites until we ourselves discovered the problem, and convinced Serverloft to unblock. Serverloft did send us an email explaining that they would not unblock the IP-range until the websites were taken offline. The email was sent 5 minutes after they cut of the access to the mail server, so we only received the email after the 4500 websites were back online.

Convincing Serverloft that their systems had blocked access on purpose was hard because Serverloft frontline support claimed that all their systems were working fine and they therefore assumed that the problem was a configuration problem on our server. They refused to help troubleshooting the issue.

Serverloft could simply have called us and asked us to deal with the situation. We would then have asked the Canadians for a warrant. If the Canadians had shown us a warrant we would have taken down the site immediately. As others have pointed out the Canadians could probably just have gone through CIRA and have the domain suspended, which would not have affected any of the other 4500 websites.

As we cannot go through every single page that our customers put on their websites we anticipate a similar situation may arise again. We have therefore asked Serverloft to revise their procedures so we at least would get a phone call before they cut our connection. They have so far refused to do so. They have answered:

your net was blocked because of hosting phishing sites. I’ve attached the information, we have, below our signature. I’m sorry, but we cant call every costumer for abuse. In some cases we’ve to respond very fast and have to block the net or server.

While I appreciate Serverloft respond fast, it is no good if the collateral damage is more than 1000 times as big. Had they called I am sure we would have found an arrangement that would satisfy both of us.

For more information: contact Ole Tange <ole@tange.dk>

The only other website I can find running on the listed IP is good-cop15.org, which is also the default vhost for that IP. It’s a site about the Copenhagen conference and links to the Yes Men hoax. Judging from the reverse lookup on the address it’s probably a virtual machine, quite possibly run by the Yes Men. It turns out that there is actually a Bruce Moore at CCIRC, but he wasn’t on duty when I called. Ec-gc.ca isn’t on any phishing list that I can find so that charge was overblown.

I don’t particularly like the Yes Men. They go from satire to impersonation. I’d have loved to see CIRA close down their ec-gc.ca domain but the domain dispute takes a long while. I can understand the letter from the CCIRC. The Yes Men website will do the most damage now, not in the time after CIRA is through with its dispute process. I find it very plausible that the Canadian Government would send such a request.

I also find it very plausible that Serverloft would issue a knee-jerk takedown. It’s relatively common for service providers to take down material immediately after a complain, especially among low margin resellers. From the WHT opinions, it sounds like that fits Serverloft. If that IP address was limited to a virtual machine run by the Yes Men, and Serverloft was okay with risking their reputation by acting on the complaint rather than following up with PiWeb, they could have at least minimized damage by only nullrouting the VM’s IP address.

There’s enough negative material on WebHostingTalk that I wouldn’t want to use Serverloft regardless of the outcome of this case. I’d like to see some official statement from PiWeb on an official channel before I believe the details though.

Update Jan 2nd 2010: It looks like Ole Tange has updated his personal website with details of the takedown.

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You can see her laying down markings in pencil. The marks are slightly bigger than the blocks we’ll be using. After she marks them, she uses a syringe to lay out drops of water along the lines. You can see in the photo that the water is beading. She fixes that by scoring over the lines so the water can absorb. After that, she can tear.

Once the paper is torn up she tosses them into a flat tupperware container that’s filled with water. Note that this paper actually has cotton in it, it’s not entirely wood pulp like printer paper. You soak it to get the sizing out, which is a starchy glue thing that keeps it stiff. Warm water works best for this. With that out you can use less force in order to press the paper and leave the indent, also known as the “kiss” of the block. The water also resists the oil so you get a cleaner print.

The extender looks like runny caulk

Now, she mixes the paint. Some tips: You don’t need printer’s ink, and you don’t need to use paint thinner or mineral spirits to clean up. In fact paint thinner or mineral spirits in the kitchen is a bad idea unless you want to be poisoned to death. We’re using oil based paint with an extender. It’s cheap. To clean up we’re using tough-on-grease palmolive. It’s also cheap. Also note that we’re using a dye based paint, not powder in an oil suspension. You can’t mix the two.  After that we’re using corn oil as a cheap alternative to printer’s medium. You might notice that cheap is a theme here. Mix and scrape and tweak to get the desired viscosity. Once that’s done it’s time to ink.

The next segments I’ve conveniently got available in video form! Apologies for the shakycam and poor framing. They were taken on impulse using my point and shoot camera. If we do another workshop we’ll bring a real video camera.

Lucite roller used to ink the mandelbrot block

It’s best to use a roller than can go over the entire block at once and take as much time as you need for this part. Alex takes her time here, explaining that a lucite roller works, or you can use a rubber one. She explains that attention to detail is probably the most important part. You will get some ink splatter away from the raised edges. Leave that for a photocopier-like effect. She thinks that’s cool, like an underground zine. Sponge it off if you want it to look perfect. Not for Alex, though. If she wants perfect she uses a laser printer. It looks like this is where you get creative and can decide things like if you want to ink the edges of the block so that you get a border when you’re pressing down with the barren.

Finally, we’re ready to do the actual pressing. Alex takes some paper out of the soak tank and blots it from both sides with a towel. She leaves it damp. She lays the paper on the inked block, then takes her time and presses it with the barren several times with even of a pressure. Watch the end of the first video for a better explanation of what to do.

Alex demonstrates this in the first video using a laser etched wood block. The second part we do the same thing but using a laser etched acrylic block. The last video explains cleanup.

Cleanup without the solvents involves a lot of scraping. Alex would first scrape off most of the ink onto tin foil if she wants to use it later, but this time she uses newsprint since it’s going to be thrown out. Eventually she just can’t scrape off any more and she’s left with a fine film. She pours on some corn oil. This dilutes the oil paint and lets her spread it around again. She can polishes it off using crumpled newsprint. After that, she uses grease busting dish soap to clean the remnants off.

All of this is very cheap to do. The tube of extender cost $45 and is the most expensive part. The barren was ten to fifteen dollars at any art store. The lucite roller was about twenty dollars. The tube we used here is still more than a third full and it’s been used for seven years. The oil pant you can find on sales for cheap. The spreaders come in three and six packs from hardware stores and cost only a couple bucks. Best of all, this all can be done in a kitchen, just like the video shows.

Whew. And that’s the end of the liveblog attempt. Take a look at Owen’s photo set on flickr and my gallery below. I have photos for the first few steps which Owen missed, and he’s got photos that I couldn’t take while I was recording video.

Here he puts into writing the same tips he gave me last year when taking an operating systems course together. (It was the first time I had to use vim on a project of a considerable size.)

It’s come up a few times, so I’ll just go and post it here: the things, in no particular order, I believe to be the bare minimum you should be able to do while you’re editing source code (and how to do them in Vim): [Easily move between files, jump-to-definition, and search for/highlight the current word.]

The first two tips on movement between files, and jumping to function definitions are the most important and have turned vim from small project editor (like, oh, university assignments excepting the operating systems course) to an editor that I can use on moderately sized projects. It doesn’t take that much practice to use the :tag command but I still fumble when using the hjkl movement keys. David was right to encourage me to use them over the arrow keys, though, as it’s the convention used in just about all of the vim commands.

In the same spirit here’s a couple things that I wish someone told me about while I was still an intern, using vim to edit config files because it was the only thing available on those Solaris boxes. They’re basic where David’s tips are intermediate, but they’re also essential:

Know your movement keys

And not just hjkl or the arrow keys. Vim likes to have upper and lowercase characters mean different things but it doesn’t always hold in the case of movement keys. Know that “b” goes to the beginning of a word and “e” goes to the end of the word. Meanwhile, “g” goes to the beginning of the document and “G” goes to the end of the document. These can be combined with commands like delete. The [t]ill movement key is especially helpful there, and I often find myself typing “dt(” which means “delete until the ( character.” Lastly, you can easily jump to a specific line number mentioned in the trace by prefixing it with a colon, so skip to line 13 with :13.

Use set

Even today half the time that I use vim it’s on someone else’s machine. The easiest way to turn on line numbering is to type “:set number” which will toggle it on. To toggle it off you use “:set nonumber”. There’s no meddling with someone’s .vimrc this way and it won’t persist, so no worries about upsetting anyone’s preferences.

Similarly, you can use set to change values of settings, like change the tabstop to five spaces with “:set tabstop=5″. This is especially useful when editing someone else’s python files where they use a different tabstop than you, and you don’t want to permanently change your tabstop but just want to edit their file.

String search and replace

Okay, now you’ve got line numbering on, so you can do a search and replace. It works based on the string search and replace regular expression. You have to specify a range, but there’s a convenient shorthand for a range of the entire file.

For lines 5-15 inclusive, you can replace “fizz” with “buzz” by:

:5,15 s/fizz/buzz/g

And to replace fizz with buzz on the entire file, use:

:% s/fizz/buzz/g

Using the regular expression here can be quite powerful, so if you’re not aware then I suggest you read up on it. If not, know that the s denotes string search and replace, the first thing between the slashes (fizz) is what you’re replacing, the second (buzz) is what you’re replacing it with, and the “g” means that you’re doing a “replace all.” Remove the trailing “g” if you only want to replace the first instance from the cursor.

And it’s not related to vim, but you can do a string search and replace on several files by using a command similar to:

perl -pi -e “s/string_to_replace/string_to_replace_with/g” *.conf

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After a bit of play with Wave my first instinct is that it’ll be great for collaborating on taking class notes. The problem is that most of my class notes involve pretty big formulas. The solution? I’m writing a gadget that takes in LaTeX code and returns a PNG suitable as a blip. I’ll be using LatexRender for that part. The downside that I can immediately see is that most of my lecture halls don’t have wifi signal, but maybe releasing the gadget will be useful to someone out there.

I don’t yet have my developer sandbox account but I’m working with the Wave gadgets tutorial. It looks like an AJAX-enabled textbox will do the trick. The state handler will check if there’s a pre-rendered PNG; if so it’ll display that, and if not it’ll query the PHP script. I’m hoping that I’ll be able to instead replace the gadget with the static PNG render once the editing of the Wave is done but I haven’t discovered the hook for that yet. I also hope that the state handler will be called immediately after init, and I think that’s the case, but judging from the documentation I’m not entirely sure.

I’m hoping to have a simple version of the gadget that just takes LaTeX within two weeks of getting my sandbox. The pipe dream feature would be a WYSIWYG editor that outputs LaTeX, so for the foreseeable future I’ll just be copying and pasting from LyX.

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John got me interested in letterpress. I don’t think I’ve seen a letterpress book in person yet, and though I have opportunity to in the Fisher Rare Book Library, I figured it’d be more fun to make my own little booklet. I don’t have a linotype, but I do have access to a 500 dpi laser etcher. I’m sure it won’t meet John’s standards but I’ve decided to attempt to make a couple printing plates out of acrylic.

Book history buffs might immediately think of intaglio printing. While it’d be easier to etch the forms for intaglio printing, I’m a bit worried that it’ll be a lot harder in the long run. It’ll certainly mean I’ve got more work since I need to clean excess ink off the plate. I’m not sure if it works with straight-down pressure rather than a roller and, if it does, it looks like it’ll need more than your standard movable type press. I think a roller is more likely to break off parts of the acrylic than pressing right down; pieces like the circle inside an engraved “a” would be easy to snap. The worst part is it’s impossible to accurately control the depth of the cut in our laser etcher, there might be a problem with the grooves or maybe it’ll be too deep or too shallow.

Instead I’ll try to carve out the equivalent to a movable type form, burning down the majority of the acrylic. The downside here is running the laser that long. A single plate will take ages, and I worry about the heat and exhaust. There’s still a chance that the acrylic will just break when put through the press.

I’m going to make a small plate for each type of printing and give it a go before I make what’ll likely be a pair of plates for a quarto print.

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