Hackaday Links: August 2, 2020

If you somehow manage to mentally separate yourself from the human tragedy of the COVID-19 pandemic, it really has provided a fascinating glimpse into how our planet operates, and how much impact seven billionpeople have on it. Latest among these revelations is that the shutdowns had a salubrious effect in at least one unexpected area: solar power. Researchers found that after the Indian government instituted mandatory lockdowns in March, output from solar power installations in Delhi increased by more than eight percent. The cause: the much-diminished smog, which let more sunlight reach solar panels. We’ve seen similar shutdown-related Earth-impact stories, from decreased anthropogenic seismicity to actually being able to see Los Angeles, and find them all delightfully revealing.

Remember Google Glass? It’s hard to forget, what with all the hype leading up to launch and the bitter disappointment of realizing that actually wearing the device wouldn’t go over well in, say, a locker room. That said, the idea of smart glasses had promise, and several startups tried to make a go of combining functionality with less out-there styling that wouldn’t instantly be seen as probable cause for being a creep. One such outfit was North, who made the more-or-less regular looking (if a bit hipsterish) Focals smart glasses. But alas, North was bought out by Google back in June, and as with so many things Google acquires, Focals smart glasses are being turned off. Anyone who bought the $600 specs will reportedly get their money back, but the features of the smart glasses will no longer function. Except, you know, you’ll still be able to look through them.

It looks like someone has finally come up with a pretty good use case for the adorably terrifying robot mini-dogs from Boston Dynamics. Ford Motors has put two of the yellow robots to work in their sprawling Van Dyke Transmission Plant in Michigan. Dubbed Fluffy and Spot (aww), the dogs wander around the plant with a suite of cameras and sensors, digitally mapping the space to prepare for possible future modifications and expansions. The robots can cover a lot of ground during the two hours that their batteries last, and are even said to be able to hitch a ride on the backs of other robots when they’re tuckered out. Scanning projects like these can keep highly trained — and expensive — engineers busy for weeks, so the investment in robots makes sense. And we’re sure there’s totally no way that Ford is using the disarmingly cute robo-pets to keep track of its employees.

We all know that the Linux kernel has some interesting cruft in it, but did you know that it can actually alert you to the fact that your printer is aflame? We didn’t either until  Editor-in-Chief Mike Szczys shared this reddit post that details the kernel function lp_check_status and how it assumes the worst if it detects the printer is online but also in “check mode.” The Wikipedia entry on the “lp0 on fire” error message has some interesting history that details how it’s not as implausible as it might seem for a printer, especially one in the early 1970s, to burst into flames under the right conditions. A toner fuser bar running amok on a modern laser printer is one thing, but imagine a printer with a fusing oven running out of control.

And finally, because 2020 is apparently the gift that can’t stop giving, at least in the weirdness department, the US Department of Defense let it slip that the office charged with investigating unidentified aerial phenomena is not quite as disbanded as they once said it was. Reported to have been defunded in 2017, the Advanced Aerospace Threat Identification Program actually appears to live on, as the Unidentified Aerial Phenomena Task Force, operating out of the Office of Naval Intelligence. Their purpose is ostensibly to study things like the Navy videos of high-speed craft out-maneuvering fighter jets, but there are whispers from former members of the task force that “objects of undetermined origin have crashed on earth with materials retrieved for study.” All this could just be a strategic misdirection, of course, but given everything else that has happened this year, we’re prepared to believe just about anything.

Simple Seismic Sensor Makes Earthquake Detection Personal

When an earthquake strikes, it’s usually hard to miss. At least that’s the case with the big ones; the dozens or hundreds of little quakes that go largely unnoticed every day are interesting too, and make sense to track. That’s usually left to the professionals, with racks of sensitive equipment and a far-flung network of seismic sensors. That doesn’t mean you can’t keep track of doings below your feet yourself, with something like this DIY seismograph.

Technically, what [Alex] built is better called a “seismic detector” since it’s not calibrated in any way. It’s just a simple sensor for detecting ground vibrations, whether they be due to passing trucks or The Big One. [Alex] lives in California, wedged between the Hayward, Calaveras, and San Andreas faults in San Jose, so there is plenty of opportunity for testing his device. The business end is a simple pendulum sensor, with a heavy metal bob hanging from a long wire inside a length of plastic pipe. Positioned close to the bob is a copper plate; the bob and the plate form an air-dielectric variable capacitor that controls the frequency of a simple 555 oscillator. The frequency is measured by a PIC microcontroller and sent to a Raspberry Pi, which displays the data on a graph. You can check in on real-time seismic activity in San Jose using the link above, or check out historical quakes, like the 7.1 magnitude Ridgecrest quake in July. [Alex]’s sensor is sensitive enough to pick up recent quakes in Peru, Fiji, and Nevada, and he even has some examples of visualizing the Earth’s core using data from the sensor. How cool is that?

We’ve seen other seismic detectors before, like this piezo-based device, or even one made from toilet parts. We like the simplicity of the capacitive sensor [Alex] used, though.

Listening To The Sounds Of The Earth

A geophone is a specially built microphone for listening to the Earth. [JTAdams] found them at a reasonable price so bought some to play with. A geophone is used to detect vibrations from earthquakes, explosions, rumbling trucks, and vibroseis vehicles. To be useful it needs an amplifier and a recording device to capture the signals.


[JTAdams] used a standard amplifier design for an LT1677 op-amp, fed the signal to an MCP3008 A/D converter, and read the output using a Raspberry Pi. A Python script records the data to a CSV file for processing. The Pi worked well because the entire setup needs to be portable to take into the field. Another Python script plots the data which is made available from a web page. A neat simple way of presenting the raw data. [JTAdams] promises more information in the future on post-processing the data. You don’t need a geophone to detect seismic waves if you build your own, but a real ‘phone will be more rugged.

Oh, what’s a vibroseis? It’s a truck with a big flat plate underneath it. The plate is hydraulically lowered to the ground until the weight of the truck is on it. The truck then causes the plate to vibrate, usually sweeping from around 10 hz to 100 hz. This infrasound pass through the ground until it is reflected back by underlying rock layers. A long string of geophones, think 1,000s of feet, detects the waves, which are recorded. In practice, many trucks are used to generate a synchronized signal of sufficient strength. Or, you can set off an explosion which is the technique used in water. Typically the information is used for oil and gas exploration.  A video of one of the trucks in action after the break.

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Hopefully Detect Trolls Before They Devour You

In the cold and mysterious wilderness of Norway, it pays to be ready for anything–especially heavy-walking trolls. The team at [nullohm] decided to prepare thoroughly for their trek into the woods to witness the Leonids meteor shower by putting together an Arduino-based “troll detector”.

The device is based on the superstition of hammering a steel spike into a tree to keep trolls away from camp. This goes one step further by including an accelerometer and LED indicators so that you can tell exactly what type of troll is just about to feast upon your tender human flesh.

When the detector is installed into a nearby tree, it takes an average seismic measurement and then looks for telltale footfalls. Even if you’re not concerned with perpetuating superstitions, you might find a use for the source code for simple seismic activity monitoring at home to supplement your miniature seismic reflector.

(Mini) Earthquake In Your Living Room

Today we stumbled upon [jimthree’s] Seismic Reflector while looking at projects that employ the Processing language we mentioned a few days ago. Utilizing a Boarduino and some vibration motors from a game controller, the Seismic Reflector does just as its name implies – rattles itself around whenever there is an earthquake. While this does seem a bit silly at first, we were fascinated to learn there have been 165 earthquakes just in the past week and almost no news reports, suddenly this device got a lot more interesting!