Hack A Folding Bike To Help You Catch Some Pike

August 3, 2020 by Kristina Panos 7 Comments

For many of us, this whole pandemic thing has produced some unexpected upsides. One of [George Turvey]’s was finding a nice new scenic route to work that goes by a lake with bike trails. [George] thought it might be nice to go fishing after work, and use a folding bike to cover a lot of ground while looking for good spots on the shore. There was just one problem — riding a bike while transporting tackle is awkward.

The bike comes with a front mount that’s meant to hold the special bags they make, so that became square one for designing a rod and tackle holder. Then [George] had to weigh the pros and cons of additive vs. subtractive methods for prototyping the holder, or at least the connection between it and the mount on the bike.

Milling won out, at least for the initial proof of concept, and result is a modular mock-up that combines a milled Kydex connector and tackle box holder with a double-barrel PVC rod holder. This way, [George] had a prototype in a fraction of the time it would have taken to design and print it. Cast your line past the break to see how fast [George] can switch gears into fishing mode.

3D printing definitely has a place in the fishing world. How else are you gonna design your own lures?

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Cryptographic LCDs Use The Magic Of XOR

August 3, 2020 by Lewin Day 8 Comments

Digital security is always a moving target, with no one device or system every being truly secure. Whether its cryptographic systems being compromised, software being hacked, or baked-in hardware vulnerabilities, it seems there is always a hole to be found. [Max Justicz] has a taste for such topics, and decided to explore the possibility of creating a secure communications device using a pair of LCDs.

In a traditional communications system, when a message is decrypted and the plaintext is displayed on screen, there’s a possibility that any other software running could capture the screen or memory state, and thus capture the secret data. To get around this, [Max]’s device uses a concept called visual cryptography. Two separate, independent systems with their own LCD each display a particular pattern. It is only when the two displays are combined together with the right filters that the message can be viewed by the user, thanks to the visual XOR effect generated by the polarized nature of LCDs.

The device as shown, working with both transparent OLEDs and traditional LCDs, is merely a proof of concept. [Max] envisions a device wherein each display is independently sourced, such that even if one is compromised, it doesn’t have the full message, and thus can’t compromise the system. [Max] also muses about the problem of side-channel attacks, and other factors to consider when trying to build a truly secure system.

We love a good discussion of cryptography and security around here; [John McMaster]’s talk on crypto ignition keys was a particular hit at Supercon last year. Video after the break.

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Linux-Fu: Help Messages For Shell Scripts And Here Documents

August 3, 2020 by Al Williams 20 Comments

Imagine that you want to output multiple lines of text in Bash, or any shell script. Maybe it’s for a help string for a particularly convoluted shell script you’re writing. You could have a separate echo command for each line. Or you could use the “here document“.

The “here document” construction takes the text between two delimiters and passes it, as if it were piped, to a command.

if [[$# == 0 ]] || [[ "$1" == "-h" ]]; then
cat << EOF
This is my help message. There are many like it but this one is mine.
My help message is my best friend.
EOF

All of the text, as written, with line breaks and spaces and all, get passed to cat and your helpful formatted message is printed to the user.

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Cheap And Effective Mosquito Trap Looks Like A Disco

August 3, 2020 by Adil Malik 34 Comments

Words cannot quite articulate the collective loathing humankind has for mosquitoes, and rightfully so! These parasite peddling, blood sucking little critters are responsible for a great deal of human suffering. Mosquito-borne diseases such as malaria still account for a significant proportion of human mortality, especially in under-developed parts of the world . So it’s no wonder that people try to reduce their numbers; see this latest $40 mosquito trap by [jacobsk]. (Video, embedded below.)

The idea is critically simple, opening up the potential for widespread deployment. The base and body of the trap are made out of three five-gallon buckets with a mini desk fan sandwiched in between, providing suction into the main trap bin. An opening is cut in the top bucket as a point of entry, and an old school incandescent blacklight is mounted in the centre, with just enough IR and UV output to entice these little vermin, who will definitely regret mistaking it for a black-light rave.

[jacobsk] also does a very good job of showing every step of its construction in his videos. Whilst this solution is purposefully low tech, check out this admittedly overcooked way of killing mosquitoes, with a laser turret.

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COVID Tracing Apps: What Europe Has Done Right, And Wrong

August 3, 2020 by Elliot Williams 63 Comments

Europe has been in COVID-containment mode for the last month, in contrast to the prior three months of serious lockdown. Kids went back to school, in shifts, and people went on vacation to countries with similarly low infection rates. Legoland and the zoo opened back up, capped at 1/3 capacity. Hardware stores and post offices are running “normally” once you’ve accommodated mandatory masks and 1.5 meter separations while standing in line as “normal”. To make up for the fact that half of the tables have to be left empty, most restaurants have sprawled out onto their terraces. It’s not really normal, but it’s also no longer horrible.

But even a country that’s doing very well like Germany, where I live, has a few hundred to a thousand new cases per day. If these are left to spread unchecked as before, the possibility of a second wave is very real, hence the mask-and-distance routine. The various European COVID-tracing apps were rolled out with this backdrop of a looming pandemic that’s tenuously under control. While nobody expects the apps to replace public distancing, they also stand to help if they can catch new and asymptomatic cases before they get passed on.

When Google and Apple introduced their frameworks for tracing apps, I took a technical look at them. My conclusion was that the infrastructure was sound, but that the implementation details would be where all of the dragons lay in wait. Not surprisingly, I was right!

Here’s an update on what’s happened in the first month of Europe’s experience with COVID-tracing apps. The good news is that the apps seem to be well written and based on the aforementioned solid foundation. Many, many people have installed at least one of the apps, and despite some quite serious growing pains, they seem to be mostly functioning as they should. The bad news is that, due to its privacy-preserving nature, nobody knows how many people have received warnings, or what effect, if any, the app is having on the infection rate. You certainly can’t see an “app effect” in the new daily cases rate. After a month of hard coding work and extreme public goodwill, it may be that cellphone apps just aren’t the panacea some had hoped.

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Pinephone Gets Thermal Imaging Backpack

August 3, 2020 by Lewin Day 12 Comments

When you buy a mass-market mobile phone, you’re making the decision to trust a long list of companies with your private data. While it’s difficult for any one consumer to fully audit even a single piece of consumer technology, there have been efforts to solve this problem to a degree. The Pinephone is one such example, with a focus on openness and allowing users to have full control over the hardware. [Martijn Braam] is a proud owner of such a device, and took advantage of this attitude to add a thermal imager to the handset.

The build is not a difficult one, thanks to the expansion-friendly nature of the Pinephone hardware. The rear of the phone sports six pogo pins carrying an I2C bus as well as power. [Martin] started by modifying the back cover of the phone with contacts to interface with the pogo pins. With this done, the MLX90640 thermal imager was attached to the case with double-sided tape and wired up to the interface.

While the 32×24 output from the sensor isn’t going to help you build cutting edge heat-seeking missiles, it’s an affordable sensor with good performance for low-end thermal imaging tasks. We’ve featured teardowns of thermal imaging hardware before, too.

See The Science Behind VR Display Design, And What Makes A Problem Important

August 3, 2020 by Donald Papp 28 Comments

VR headsets are more and more common, but they aren’t perfect devices. That meant [Douglas Lanman] had a choice of problems to address when he joined Facebook Reality Labs several years ago. Right from the start, he perceived an issue no one seemed to be working on: the fact that the closer an object in VR is to one’s face, the less “real” it seems. There are several reasons for this, but the general way it presents is that the closer a virtual object is to the viewer, the more blurred and out of focus it appears to be. [Douglas] talks all about it and related issues in a great presentation from earlier this year (YouTube video) at the Electronic Imaging Symposium that sums up the state of the art for VR display technology while giving a peek at the kind of hard scientific work that goes into identifying and solving new problems.

[Douglas] chose to address seemingly-minor aspects of how the human eye and brain perceive objects and infer depth, and did so for two reasons: one was that no good solutions existed for it, and the other was that it was important because these cues play a large role in close-range VR interactions. Things within touching or throwing distance are a sweet spot for interactive VR content, and the state of the art wasn’t really delivering what human eyes and brain were expecting to see. This led to years of work on designing and testing varifocal and multi-focal displays which, among other things, were capable of presenting images in a variety of realistic focal planes instead of a single flat one. Not only that, but since the human eye expects things that are not in the correct focal plane to appear blurred (which is itself a depth cue), simulating that accurately was part of things, too.

The entire talk is packed full of interesting details and prototypes. If you have any interest in VR imaging and headset design and have a spare hour, watch it in the video embedded below.

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