Magic Mirror on the Wall, “Is Pi or ESP, Fairest of All?”

“What’s the weather like, honey?” “I don’t know. Let me check the mirror.”  The mirror?

Both [Dylan Pierce] and [Dani Eichorn] have mirror projects that display the weather. They took two different approaches which makes for an interesting comparison. [Dylan] uses a Rapsberry Pi with an actual monitor behind the mirror. [Dani] puts an OLED behind the mirror driven by a ESP8266.  It appears there is more than one way to hack a mirror, or anything, which is what makes hacking fun.

[Dani] started with a picture frame, adding tinting film to the glass so it would reflect. A small section of tint was removed to allow the OLED to be seen. The ESP8266 software connects to the Weather Underground to get the latest information.

The Raspberry Pi version by [Dylan] puts a 27″ monitor behind the mirror. That is either terribly impressive or way over the top but seeing Linux boot behind the mirror makes it worth the effort. The Pi generates a web page which makes this adaptable as a general purpose kiosk.

A video of [Dani’s] mirror in operation, after the break.

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Must-Have Overkill Christmas Tree Lights

The yuletide fire is out, so we’re starting to receive this year’s Christmas hacks. [Chris] sent us his awesome video-mapped tree lighting hack. His project made clever use of a bunch of cool tools, so even if you’re not thinking forward to next December, it’s worth a look. Still images don’t do it justice; check out the video below the break.

The end result is an addressable string of WS2812B LEDs connected up to a Raspberry Pi Zero that can display a video image even though it’s wrapped around a roughly cone-shaped (pine) object. But this is actually more impressive than you’d think at first; how would you map a flat image to a string of LEDs wrapped around a tree?

[Chris]’s solution was to write a routine that lit up the LEDs in a unique pattern and then detected them using OpenCV and a webcam, making the mapping directly. He then samples images from a video at exactly the points where the pixels are located on the tree, and sends this data out to the LEDs.

The basic framework here should transform fairly easily into a generic image-mapping procedure with randomly located LEDs, so we think it’s a hack that’ll outlast the season. And because it runs on the Pi Zero, everything is in Python so it’d be a good project for beginners to replicate. However, the code section on the project page still lists it as coming soon. We hope so!

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Yet Another Pi Zero USB Hub

The Raspberry Pi Zero was back in stock at Adafruit this week – for about eight minutes. That means a few more people get Pi Zeros, many more will put them up on eBay, and everyone is working on their own version of a Pi Zero USB hub. The latest version of a Pi Zero hub comes from [Nate], and he’s doing this one right. His Pi USB adapter adds four USB ports and features not found in other DIY USB hubs like fuses and ESD protection.

As with other Pi Zero USB hub add-ons, this build relies on a USB hub controller, a few passives, and not much else. The chip used in this hub is the FE1.1s chip, a highly integrated 4-port hub controller that can be found through the usual Chinese resellers. This hub controller doesn’t require much, just a 12MHz crystal, a few passives, and four USB jacks.

Of particular interest is how [Nate] is connecting this hub to the Pi Zero. He’s left the option open for using either a USB cable, or soldering the USB’s differential pairs directly between the Pi and the hub. In either case, the hub should work, and with the addition of the zeners, fuses, and other parts that keep the hub from frying itself, [Nate] might have a very nice project on his hands.

32C3: Inside Glorious Leader’s Operating System

North Korea is a surveillance state propped up by a totalitarian government infamous for human rights abuses and a huge military that serves the elite while the poor are left to fight over scraps. Coincidently, that’s exactly what North Korea says about the United States.

There is one significant difference between the two countries: North Korea has developed its own operating system for its citizens, called Red Star OS. It’s an operating system based on Linux, but that has a few interesting features that allow Glorious Leader to take care of his citizens. A deep teardown of what has gone into the development of Red Star OS hasn’t been available until now, with [Florian Grunow] and [Niklaus Schiess]’s talk at the Chaos Communication Congress this week.

Kim Jong-Un with an iMac
Kim Jong-Un with an iMac

The first question anyone must ask when confronted with an operating system built by a country that doesn’t have much electricity is, “why?” This question can only be answered philosophically; the late Kim Jong-Il stressed the importance of North Korea developing “their own style” of programming, and not relying on western operating systems. Nearly everything in Red Star has been modified, with a custom browser called Naenara, a crypto tool, a clone of Open Office, a software manager, and a custom music composition tool. Red Star also had to have the look and feel of OS X; that is, after all, what Glorious Leader uses.

Red Star goes much deeper than custom browsers and a desktop theme. There are other, subtler components inside the OS. There is a program that verifies the integrity of the system by checking signatures of the custom files against a database. If a file has been tampered with, the system reboots. Since this tamper check runs on bootup, Red Star makes it nearly impossible to modify files for study. This is one of the big features designed into Red Star – system integrity is paramount.

There are other custom bits of software that hide files from the user even if they have root, and a ‘virus scanner’ that is anything but. This virus scanner checks documents for patterns that, when put through Google Translate, are strange, weird, and somewhat understandable. Phrases like, “punishment”, “hungry”, and “strike with fists” are detected in all documents, and depending on what the developers decide, these documents can be deleted on a whim.

While scanning a system for documents that contain non-approved speech is abhorrent enough, there’s another feature that would make any privacy advocate weep. Media files including DOCX, JPG, PNG, and AVI files are watermarked by every computer that opened the files. This allows anyone to track the origin of a file, with the obvious consequences to free speech that entails.

While most people in the US consider North Korea to be a technological backwater and oppressive regime, the features that make Red Star OS useful to the DPRK are impressive. The developers touched nearly everything in Red Star, and the features inside it are rather clever and make their style of surveillance very useful. They’re also doing this without any apparent backdoors or other spycraft; they’re putting all their surveillance out in the open for all to see, which is, perhaps, the best way to go about it.

Sourcing Your CNC Tools in 2016: Buy Them

Hobbyist 3D printers have had a home in the maker space for years now. Along the way, they’ve left a mark in our imaginations. They’ve tickled our fancy for watching a computer orchestrated symphony written in G-code hum away while cranking out parts. They’ve opened a door to the idea that while computer controlled machines may be decades old, having one or two homebrew setups in our garage might not be as far-fetched as we first thought. Now that we’ve seen the steppers and linear slides that go into these setups, it’s not unreasonable for many of us to start asking: What else? Perhaps a computer numerically controlled (CNC) lathe, mill, or even a laser cutter–anything that would add to the vocabulary of tools and techniques that we’re starting to build at home.

VSlot linear rail system for building multiaxis linear actuator systems
VSlot linear rail system for building multiaxis linear actuator systems

Since 3D printers have become somewhat commonplace, it’s not too difficult to find commodity spare parts spilling to the surface of online vendors’ websites. We can even find kit versions for building our own variants. Now that the notion of CNC-at-home is here to stay, the question for 2016 is: do we build our own CNC tools or buy them?

Despite the countless CNC build logs, extruded aluminum kits, and open source G-code interpreters, I’m still convinced that unless your needs are truly custom, buying the machine that fits your needs will have you putting together projects faster and with far less maintenance than you’d need if you assembled the machine yourself. In what follows, I thought I’d explore a few machines that we can find today in 2016 that make the dream of desktop fabrication a reality.

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Stepping out in Style with Top Hat Navigation

Wearable tech is getting to be a big thing. But how we interface with this gear is still a bit of a work in progress. To explore this space, [Bruce Land]’s microcontroller course students came up with an acoustic interface to assist with navigation while walking. With style, of course.

[Bruce], from the Cornell University School of Electrical and Computer Engineering, has been burning up the Hackaday tips line with his students’ final projects. Here’s the overview page for the Sound Navigation Hat. It uses a PIC32 with GPS and compass. A lot of time was spent figuring out how to properly retrieve and parse the GPS data, but for us the interesting bits on that page are how the directional sound was put together.

Audio tones are fed to earbuds with phase shift and amplitude to make it seem like the sound is coming from the direction you’re supposed to walk. Navigation is all based on pre-programmed routes which are selected using a small LCD screen and buttons. One thing’s for sure, the choice of headwear for the project is beyond reproach from a fashion standpoint – engineering has a long history with the top hat, and we think it’s high time it made a comeback.

Is this a practical solution to land navigation? Of course not. But it could be implemented in smartphone audio players for ambient turn-by-turn navigation. And as a student project, it’s a fun way to demonstrate a novel interface. We recently covered a haptic navigation interface for the visually impaired that uses a similar principle. It’ll be interesting to see if either of these interfaces goes anywhere.

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Messages From Hell: Human Signal Processing

Despite the title, there’s no religious content in this post. The Hell in question is the German inventor [Rudolph Hell]. Although he had an impressive career, what most people remember him for is the Hellschreiber–a device I often mention when I’m trying to illustrate engineering elegance. What’s a Hellschreiber? And why is it elegant?

The first question is easy to answer: the Hellschreiber is almost like a teletype machine. It sends printed messages over the radio, but it works differently than conventional teletype. That’s where the elegance comes into play. To understand how, though, you need a little background.

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