How Hacker News Page Rankings Really Work

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Page rankings are the secret sauce of websites that automatically aggregate user submissions. The basic formula used by Hacker News was published a few years back. But there are several pieces of the puzzle that are missing from that specification. [Ken Shirriff] recently published an analysis that digs deeper to expose the article penalization system used by Hacker News’ ranking engine.

One might assume that the user up and down votes are what determine a page’s lifespan on the front page. But it turns out that a complex penalization system makes a huge difference. It takes into account keywords, and domain names but also weighs controversy. It’s a bit amusing to note that this article on the topic was itself penalized, knocking it off of the front page.

You can get the full details of the system from his post, but we found his investigation methods to be equally interesting. He scraped two pages of the news feed every minute using Python and the Beautiful Soup package (a pretty common scraping practice). This data set allowed him to compare the known algorithm with actual results. What was left were a set of anomalies that contained enough sense for him to reverse engineer the unpublished formulas being used.

The Making of the WaterColorBot

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Remember the WaterColorBot? Ever wonder what goes into manufacturing a kit like it? Well the folks over at Evil Mad Scientist just spilled the beans.

It’s a great insight on how these kits are typically made in a manufacturing environment, especially if you happen to be the founders of a rather successful Kickstarter project like the WaterColorBot by [SuperAwesomeSylvia]. The article goes into great detail on minimizing material waste during CNC routing, mass producing laser engravings using a jig, hardware assembly, and finicky assembly of some of the more complex components. Not to mention boxing, storing, and packaging the finished products!

We’re happy to hear the WaterColorBot is officially shipping now, and available for purchase — Seems like they were only off by a month or so for their kickstarter delivery goals. Remember our recent post about one of these WaterColorBots out in the wild? One was used to create art using inputs from driving a real car!

Running a Laundromat with an Arduino

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[Hubert] sent us a tip about a friend’s project to rescue a laundromat from its failing electronics. We’re not entirely sure what went wrong with the old control center, but considering a replacement would have cost nearly 25,000 EUR, we think [Stefan] found the perfect solution: he gave it an Arduino and Android overhaul (translated).

Although [Stefan] explains that the boards were defective, perhaps one of our German readers can help us out with a more specific translation. More clear, however, are the steps taken to upgrade the system. The situation at the laundromat was a bit of an emergency: there was no way for customers to pay for use of the machines. As a result, [Stefan] had free reign to overhaul things as he saw fit. He decided to remove the complex button setup in favor of a touchscreen Android tablet, which provided users with a simple interface to make selections. The tablet serves only as an input device. The heavy lifting is handled by an Arduino Mega 2560, which hooks up to what remains of the original system and controls the 27 machines in the laundromat.

[Stefan] admits that he isn’t a particular fan of the Arduino, but that for the price, it’s a tough solution to beat. He’s not the only one overhauling with Arduinos. Check out some other examples of upgraded machines, like the Arduino-enhanced PopCARD vending machine.

UPDATE: [Andreas] sent in a better translation of the project page which we’ve included below. He worries his written English isn’t the best, but we think it is a lot easier to understand than the machine translation. Thank you for you work [Andreas!]

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Sniffing Data from Radio-Controlled Bus Stop Displays

A few weeks ago in Finland [Oona] discovered a radio data stream centered around 76KHz in a FM broadcast and she recently managed to decode it. This 16,000bps stream uses level-controlled minimum-shift keying (L-MSK) which detection can be quite tricky to implement. She therefore decoded the stream by treating the received signal as non-coherent binary FSK, which as a side effect increased the bit error probability. [Oona] then understood that the stream she was getting was the data broadcast by Helsinky buses to the nearby bus stop timetable displays. She even got lucky when she observed a display stuck in the middle of its bootup sequence, displaying a version string. This revealed that the system is called IBus and made by the Swedish company Axentia. However their website didn’t provide the specs for their proprietary protocol. After many hours of sniffing and coding, [Oona] successfully implemented the five layer protocol stack in Perl and can now read the arrival times of the nearby buses from her apartment.

Hacking and Philosophy: Crackdown Part III

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“Law and Order” may be my favorite chapter of Hacker Crackdown: it covers the perspective of the early 90’s seizures and arrests from the perspective of law enforcement. While the chapter has its flaws, I highly recommend it; [Sterling] treats both sides with patience and understanding, revealing how similarly adrift everyone was (and to some extent, remains) in the uncertainty of cyberspace. I also recommend the [Gail Thackeray] / [Dead Addict] joint talk from DEFCON 20 as an accompanying piece to this chapter, as it bridges the twenty-year gap between Crackdown‘s publication and today—and [Thackeray] herself is the focus of this chapter.

As always, everyone is welcome in our weekly discussion, even if you haven’t been keeping up with our progress through Hacker Crackdown. You can download it for free as an audiobook, too! Onward for more!

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Circuit Stickers

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One of our tipsters just sent an interesting crowd funding project our way. They’re called Circuit Stickers and are a very creative way to get basic electronics into children’s hands through arts and crafts.

The project is the brainchild of [Bunnie] and [Jie Qi]. [Bunnie] is a hacker, and a Director of Studio Kosagi, a small manufacturing outfit in Singapore. [Jie] on the other hand is a PhD student at the MIT Media Lab, who focuses her research on combining electronics and programming with arts and crafts. They came up with this idea to bridge the gap that exists between electronics and the arts, and the stickers are a great start. They allow anyone to learn basic electronics in a very easy and friendly way, using skills we all learned as children, drawing and sticking stickers on everything.

The current offering includes LED stickers, effects stickers (to control the LEDs), sensors, microcontrollers, and even breakout boards. They are all in sticker form, and can be connected together using  conductive fabric, thread, carbon-based paint, copper tape, pencil graphite, and really, anything conductive. They have already manufactured thousands of the stickers and everything is working as designed, so the crowdfunding campaign isn’t to raise funds to continue research, or even to start their company. It’s more of getting it out there, and getting these stickers into children’s hands to raise the next generation of hackers from a young age.

The video after the break gives a great overview of the project, and if anything we think it’ll give you some great ideas on children’s electronics projects.

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EmuDroid 4: An Android Gaming Controller

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[Carnivore] over at Droid Build is working on a very awesome Android Gaming Controller called the EmuDroid 4.

It’s a work in progress at the moment, but so far it looks utterly fantastic. He is combining an android tablet with a USB SNES controller, an OTG adapter, and an inductive charging unit. He’s cramming them all into a custom designed, 3D printed controller body, which is semi-reminiscent of an Xbox 360 controller — minus the joysticks.

The forum posts go over his current progress and outline the ups and downs of 3D printing a project as precise as this. There is everything from designing it in segments to suit the small build volume of his UP 3D printer, to dealing with issues like delamination from the print bed, and seamlessly bonding the parts together. It’s a great learning experience, and we love to see projects in progress like this. Best of all, he’s planning on giving it away for FREE when it’s complete!

We’ve seen lots of modified controllers used with Android before, but we think this integrated solution really takes the cake, at least for now anyway!

[Thanks Tony!]

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