Saving The Planet With Carefully Cut Paper

You may not think much of origami or its cousin-with-cutouts kirigami, but the latter could (and already is) helping to save the planet. But let’s back up a bit.

Most readers will be familiar with origami, the Japanese art of folding paper. But there is also kirigami, which uses a series of cuts to produce 3D shapes from 2D stock. Turns out that if you cut paper just right, you can turn it into highly-recyclable packaging that even interlocks with itself, negating the need for folding or even tape.

The video after the break takes a look at 3M’s Scotch Cushion Lock™ protective wrap through the eyes of its inventor, Tom Corrigan. It all started when 3M wanted to create a self-assembling box from a flat piece of cardboard.

So far, that particular invention hasn’t come to fruition, but after many long nights with paper and X-Acto knives, Tom came up with a honeycomb design with strong vertical walls that absorb energy much like bubble wrap or packing peanuts. The toothiness of each honeycomb wall adds height which adds strength, and allows the packaging to interlock with itself.

Not only is this packaging easier to recycle, it takes up way less space than other packaging alternatives. Once expanded, a 1,000 square foot roll of this stuff is equal to 2,500 square feet of bubble wrap, which constitutes about a dozen rolls.

Now, what to do about all that expanded polystyrene packaging still out there? With the right tool, you can turn it into insulation.

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This Week In Security: Terrapin, Seized Unseized, And Autospill

There’s a new SSH vulnerability, Terrapin (pdf paper), and it’s got the potential to be nasty — but only in an extremely limited circumstance. To understand the problem, we have to understand what SSH is designed to do. It replaces telnet as a tool to get a command line shell on a remote computer. Telnet send all that text in the clear, but SSH wraps it all inside a public-key encrypted tunnel. It was designed to safely negotiate an unfriendly network, which is why SSH clients are so explicit about accepting new keys, and alerting when a key has changed.

SSH uses a sequence counter to detect Man-in-the-Middle (MitM) shenanigans like packet deletion, replay, or reordering. That sequence isn’t actually included in the packet, but is used as part of the Message Authentication Check (MAC) of several encryption modes. This means that if a packet is removed from the encrypted tunnel, the MAC fails on the rest of the packets, triggering a complete connection reset. This sequence actually starts at zero, with the first unencrypted packet sent after the version banners are exchanged. In theory, this means that an attacker fiddling with packets in the pre-encryption phase will invalidate the entire connection as well. There’s just one problem.

The innovation from the Terrapin researchers is that an attacker with MitM access to the connection can insert a number of benign messages in the pre-encryption phase, and then silently drop the first number of messages in the encrypted phase. Just a little TCP sequence rewriting for any messages between, and neither the server nor client can detect the deception. It’s a really interesting trick — but what can we do with it?

For most SSH implementations, not much. The 9.6 release of OpenSSH addresses the bug, calling it cryptographically novel, but noting that the actual impact is limited to disabling some of the timing obfuscation features added to release 9.5.

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Giant Demonstrator Explains How DLP Projectors Work

Texas Instruments developed digital mirror devices, and the subsequent digital light processing (DLP) projector, starting in the late 1980s. The technology is a wondrous and fanciful application of micro-scale electronics and optics. Most of us that have tangled with these devices have had to learn their mode of operation from diagrams and our own imagination. But what if you just built one at a large enough scale that you could see how it worked? Well, [jbumstead] did just that!

A real Digital Micromirror Device (DMD) consists of hundreds of thousands of mirrors, which would be impractical to recreate. This build settles for a simpler 5×5 array made using half-inch square mirrors. It uses solenoids to move each individual mirror between a flat and angled position to create the display. The solenoids are all under the command of an Arduino Mega which controls the overall state of the display and shows various patterns.

It’s not perfect, with the mirrors not quite matching in angles at all times, but it demonstrates the concept perfectly well. When you see it in action with light bouncing off it, you can easily understand how this could be used to make a display of many thousands of pixels in a projector arrangement. We’ve featured some other DLP hacks before, too, so dive in if you’re interested.

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Open Source DC UPS Keeps The Low-Voltage Gear Going

We all like to keep our network gear running during a power outage — trouble is, your standard consumer-grade uninterruptible power supply (UPS) tends to be overkill for routers and such. Their outlet strips built quickly get crowded with wall-warts, and why bother converting from DC to AC only to convert back again?

This common conundrum is the inspiration for [Walker]’s DC UPS design, which has some interesting features. First off, the design is open source, which of course invites tinkering and repurposing. The UPS is built for a 12 volt supply and load, but that obviously can be changed to suit your needs. The battery bank is a 4S3P design using 18650 cells, and that could be customized as well. There’s an ideal diode controller that prevents DC from back-feeding into the supply when the lights go out, and a really interesting synchronous buck-boost converter in place of the power management chip you’d normally see in a UPS. The converter chip takes a PWM signal from an RP2040; there’s also an ESP32 onboard for web server and UI duties as well as an STM32 to run the BMS. The video below discusses the design and shows a little of the build.

We’ve seen a spate of DC UPS designs lately, some more elaborate than others. This one has quite a few interesting chips that most of us don’t normally deal with, and it’s nice to see how they’re used in a practical design.

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Zerowriter Promises Zero Distractions While Writing

As great as full-blown desktop computers may be for web surfing, gaming, and what have you, they are theaters of distraction when it comes time to write. And while there are machines out there purpose-built for writing, the price tags run awfully high for what they are, which is essentially a microprocessor handling a keyboard and an E-ink display.

So, why not build one yourself, then? That’s the idea behind the Zerowriter, which, as you may have guessed, is based on the Raspberry Pi Zero. The Zero 2 W to be exact: [zerowriter]  says that the extra power over the original Zero is quite useful.

In addition, there’s a 4.2″ Waveshare E-ink display and the Vortex Core 40% keyboard inside the 3D-printed enclosure. The design is based on the Penkesu computer, although in the Zerowriter, the Pi sits behind the screen instead of underneath the keyboard. [zerowriter] built an application on top of the Waveshare demo program that’s easy to use and modify.

The price tag for this build comes in around $200, which is a fraction of similar commercial products. Most of the cost is in this particular keyboard, although 40%s are, broadly speaking, not cheap. We would love to see someone make a keyboard for this.

Looking to make something a bit bigger? Be sure to check out the MUSE.

A series of plates and tubes sits in a tank of water. The plates are square with what looks to be a white coating.

Desalinating Water With The Sun

Getting fresh water from salt water can be difficult to do at any kind of scale. Researchers have developed a new method of desalinating water that significantly reduces its cost. [via Electrek]

By mimicking the thermohaline circulation of the ocean, the researchers from MIT and Shanghai Jiao Tong University were able to solve one of the primary issues with desalination systems, salt fouling. Using a series of evaporator/condenser stages, the seawater is separated into freshwater and salt using heat from the sun.

Evaporating water to separate it from salt isn’t new, but the researchers took it a step further by tilting the whole contraption and introducing a series of tubes to help move the water along and create eddy currents. These currents help the denser, saltier water move off of the apparatus and down deeper into the fluid where the salt doesn’t cause an issue with the device’s operation. The device should have a relatively long lifetime since it has no moving parts and doesn’t require any electricity to operate.

The researchers believe a small, suitcase-sized device could produce water for a family for less than the cost of tap water in the US. The (paywalled) paper is available from Joule.

If you’re curious about other drinking water hacks, check out this post on Re-Imagining the Water Supply or this previous work by the same researchers.

VU Meter Built With Neat Graphical VFD Display

VFD displays are beloved for their eerie glow that sits somewhere just off what you’d call blue. [mircemk] used one of these displays to create an old-school VU meter that looks straight out of a 1970s laboratory. 

The build uses an Arduino Nano as the brains of the operation, which uses its analog inputs to process incoming audio into decibel levels for display on a VU meter. It’s then charged with driving a GP1287 VFD display. Unlike some VFDs that have preset segments that can be illuminated or switched off, this is a fully graphical dot matrix display that can be driven as desired. Thus, when it’s not acting as a bar graph VU meter, it can also emulate old-school moving-needle meters. Though, it bears noting, the slow updates the Arduino makes to the display means it’s kind of like those dodgy skeumorphic music apps of the 16-bit era; i.e. it’s quite visually jerky.

Overall, it’s a neat project that demonstrates how to work with audio, microcontrollers, and displays all in one. We’ve featured other projects from [mircemk] before, too, almost all of which appear in the same blue and grey project boxes. Video after the break.

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