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The Linux Throwie: A Non-Spacefaring Satellite

November 20, 2018 by 42 Comments

Throwies occupy a special place in hardware culture — a coin cell battery, LED, and a magnet that can be thrown into an inaccessible place and stick there as a little beacon of colored light. Many of us will fondly remember this as a first project. Alas, time marches inevitably on, and launching cheerful lights no longer teaches me new skills. With a nod to those simpler times, I’ve been working on the unusual idea of building a fully functional server that can be left in remote places and remain functional, like a throwie (please don’t actually throw it). It’s a little kooky, yet should still deliver a few years of occasional remote access if you leave it somewhere with sunlight.

A short while ago, I described the power stages for this solar-powered, cloud accessible Linux server. It only activates on demand, so a small solar cell and modest battery are sufficient to keep the whole show running.

Where we left off, I had a solar cell that could charge a battery, and provide regulated 12 V and 5 V output. For it to be a functional device, there are three high level problems to solve:

  1. It must be possible to set up the device without direct physical access
  2. You must be able to remotely turn it on and off as needed.
  3. It needs to be accessible from the Internet.

The funny thing is, this hardware reminds me of a satellite. Of course it’s not meant to go into space, but I do plan to put it somewhere not easy to get to again, it runs off of solar power, and there’s a special subsystem (ESP8266) to tend the power, check for remote activation, and turn the main computer (Raspberry Pi 3) on and off as necessary. This sounds a lot like space race tech, right?

As I have a bit more code than usual to share with you today, I’ll discuss the most interesting parts, and provide links to the full firmware files at the end of the article.

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Flagging Down Aliens With World’s Biggest Laser Pointer

November 20, 2018 by 86 Comments

As you’re no doubt aware, humans are a rather noisy species. Not just audibly, like in the case of somebody talking loudly when you’re in a movie theater, but also electromagnetically. All of our wireless transmissions since Marconi made his first spark gap broadcast in 1895 have radiated out into space, and anyone who’s got a sensitive enough ear pointed into our little corner of the Milky Way should have no trouble hearing us. Even if these extraterrestrial eavesdroppers wouldn’t be able to understand the content of our transmissions, the sheer volume of them would be enough to indicate that whatever is making all that noise on the third rock orbiting Sol can’t be a natural phenomena. In other words, one of the best ways to find intelligent life in the galaxy may just be to sit around and wait for them to hear us.

Of course, there’s some pesky physics involved that makes it a bit more complicated. Signals radiate from the Earth at the speed of light, which is like a brisk walk in interstellar terms. Depending on where these hypothetical listeners are located, the delay between when we broadcast something and when they receive it can be immense. For example, any intelligent beings that might be listening in on us from the closest known star, Proxima Centauri, are only just now being utterly disappointed by the finale for “How I Met Your Mother“. Comparatively, “Dallas” fans from Zeta Reticuli are still on the edge of their seats waiting to find out who shot J.R.

But rather than relying on our normal broadcasts to do the talking for us, a recent paper in The Astrophysical Journal makes the case that we should go one better. Written by James R. Clark and Kerri Cahoy,  “Optical Detection of Lasers with Near-term Technology at Interstellar Distances” makes the case that we could use current or near-term laser technology to broadcast a highly directional beacon to potentially life-harboring star systems. What’s more, it even theorizes it would be possible to establish direct communications with an alien intelligence simply by modulating the beam.

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[Ben Krasnow] Gasses MEMS Chips, For Science

November 20, 2018 by 61 Comments

Why in the world does helium kill iPhones and other members of the Apple ecosystem? Enquiring minds want to know, and [Ben Krasnow] has obliged with an investigation of the culprit: the MEMS oscillator. (YouTube, embedded below.)

When we first heard about this, courtesy in part via a Hackaday post on MRI-killed iPhones, we couldn’t imagine how poisoning a micro-electromechanical system (MEMS) part could kill a phone. We’d always associated MEMS with accelerometers and gyros, important sensors in the smartphone suite, but hardly essential. It turns out there’s another MEMS component in many Apple products: an SiT 1532 oscillator, a tiny replacement for quartz crystal oscillators.

[Ben] got a few from DigiKey and put them through some tests in a DIY gas chamber. He found that a partial pressure of helium as low as 2 kPa, or just 2% of atmospheric pressure, can kill the oscillator. To understand why, and because [Ben] has a scanning electron microscope, he lapped down some spare MEMS oscillators to expose their intricate innards. His SEM images are stunning but perplexing, raising questions about how such things could be made which he also addresses.

The bottom line: helium poisons MEMS oscillators in low enough concentrations that the original MRI story is plausible. As a bonus, we now understand MEMS devices a bit better, and have one more reason never to own an iPhone.

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Of Roach Killer And Rust Remover: Sam Zeloof’s Garage-Made Chips

November 19, 2018 by 28 Comments

A normal life in hacking, if there is such a thing, seems to follow a predictable trajectory, at least in terms of the physical space it occupies. We generally start small, working on a few simple projects on the kitchen table, or if we start young enough, perhaps on a desk in our childhood bedroom. Time passes, our skills increase, and with them the need for space. Soon we’re claiming an unused room or a corner of the basement. Skills build on skills, gear accumulates, and before you know it, the garage is no longer a place for cars but a place for pushing back the darkness of our own ignorance and expanding our horizons into parts unknown.

It appears that Sam Zeloof’s annexation of the family garage occurred fairly early in life, and to a level that’s hard to comprehend. Sam seems to have caught the hacking bug early, and by the time high school rolled around, he was building out a remarkably well-equipped semiconductor fabrication lab at home. Sam has been posting his progress regularly on his own blog and on Twitter, and he dropped by the 2018 Superconference to give everyone a lesson on semiconductor physics and how he became the first hobbyist to produce an integrated circuit using lithographic processes.

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How The Xbox Was Hacked

November 19, 2018 by 38 Comments

The millennium: a term that few had any use for before 1999, yet seemingly overnight it was everywhere. The turning of the millenium permeated every facet of pop culture. Unconventional popstars like Moby supplied electronica to the mainstream airwaves while audiences contemplated whether computers were the true enemy after seeing The Matrix. We were torn between anxiety — the impending Y2K bug bringing the end of civilization that Prince prophesied — and anticipation: the forthcoming release of the PlayStation 2.

Sony was poised to take control of the videogame console market once again. They had already sold more units of the original PlayStation than all of their competition combined. Their heavy cloud of influence over gamers meant that the next generation of games wasn’t going to start in until the PS2 was on store shelves. On the tail of Sony announcing the technical specs on their machine, rumors of a new competitor entering the “console wars” began to spread. That new competitor was Microsoft, an American company playing in a Japanese company’s game.
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Hack My House: Opening Raspberry Pi To The Internet, But Not The Whole World

November 14, 2018 by 29 Comments

If you’ve followed along with our series so far, you know we’ve set up a network of Raspberry Pis that PXE boot off a central server, and then used Zoneminder to run a network of IP cameras. Now that some useful services are running in our smart house, how do we access those services when away from home, and how do we keep the rest of the world from spying on our cameras?

Before we get to VPNs and port forwarding, there is a more fundamental issue: Do you trust your devices? What exactly is the firmware on those cheap cameras really doing? You could use Wireshark and a smart switch with port mirroring to audit the camera’s traffic. How much traffic would you need to inspect to feel confident the camera never sends your data off somewhere else?

Thankfully, there’s a better way. One of the major features of surveillance software like Zoneminder is that it aggregates the feeds from the cameras. This process also has the effect of proxying the video feeds: We don’t connect directly to the cameras in order to view them, we connect to the surveillance software. If you don’t completely trust those cameras, then don’t give them internet access. You can make the cameras a physically separate network, only connected to the surveillance machine, or just set their IP addresses manually, and don’t fill in the default route or DNS. Whichever way you set it up, the goal is the same: let your surveillance software talk to the cameras, but don’t let the cameras talk to the outside world.

Edit: As has been pointed out in the comments, leaving off a default route is significantly less effective than separate networks. A truly malicious peice of hardware could easily probe for the gateway.

This idea applies to more than cameras. Any device that doesn’t need internet access to function, can be isolated in this way. While this could be considered paranoia, I consider it simple good practice. Join me after the break to discuss port forwarding vs. VPNs.

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Mechanisms: Lead Screws And Ball Screws

November 13, 2018 by 52 Comments

Translating rotary motion to linear motion is a basic part of mechatronic design. Take a look at the nearest 3D-printer or CNC router — at least the Cartesian variety — and you’ll see some mechanism that converts the rotation of the the motor shafts into the smooth linear motion needed for each axis.

Hobby-grade machines are as likely as not to use pulleys and timing belts to achieve this translation, and that generally meets the needs of the machine. But in some machines, the stretchiness of a belt won’t cut it, and the designer may turn to some variety of screw drive to do the job.

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