Plan To Jam Mobile Phones In Schools Is Madness

March 24, 2023 by Lewin Day 329 Comments

Mobile phones in schools. If you’re a teacher, school staffer, or a parent, you’ve likely got six hundred opinions about this very topic, and you will have had six hundred arguments about it this week. In Australia, push has come to shove, and several states have banned the use of mobile phones during school hours entirely. Others are contemplating doing the same.

In the state of New South Wales, the current opposition party has made it clear it will implement a ban if elected. Wildly, the party wants to use mobile phone jamming technology to enforce this ban whether students intend to comply or not. Let’s take a look at how jammers work in theory, and explore why using them in schools would be madness in practice.

Continue reading “Plan To Jam Mobile Phones In Schools Is Madness” →

Hackaday Podcast 211: Pocket Sundial, Origami Llama, PCB Spacemouse

March 24, 2023 by Kristina Panos 3 Comments

This week, Editor-in-Chief Elliot Williams and Contributor Emeritus Kristina Panos chewed the fat about the coolest hacks of the previous week. But first, a bit of news — our Low Power Challenge fizzled out this week, and boy did we have a lot of entries at the last minute. We love to see it though, and we’re going to get judging ASAP.

Don’t forget, this weekend is Hackaday Berlin! Livestreaming for this one may be iffy, but we’ll have the talks up for you eventually, so don’t fret too much if you can’t make it in the flesh this time.

Kristina definitely got What’s That Sound this week, but her answer will of course be bleeped out. Then it’s on to the hacks, beginning with a 6-DoF controller that does everything in interesting ways and a printed shredder that eats like a goat. From there we cover bolt dispensers, coffee grinders with Bluetooth weighing, camera calibration, and a $50 pen plotter that’s definitely a hack. Finally, we discuss the virtues of physicality when it comes to SIM cards and recorded music.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

And/or download it and listen offline.

Continue reading “Hackaday Podcast 211: Pocket Sundial, Origami Llama, PCB Spacemouse” →

Low-Power Challenge: Making An Analog Clock Into A Calendar With A 50-Year Life

March 24, 2023 by Dan Maloney 24 Comments

You have to be pretty ambitious to modify a clock to run for 50 years on a single battery. You also should probably be pretty young if you think you’re going to verify your power estimates, at least in person. According to [Josh EJ], this modified quartz analog clock, which ticks off the date rather than the time, is one of those “The March of Time” projects that’s intended to ~~terrify~~ incentivize you by showing how much of the year is left.

Making a regular clock movement slow down so that what normally takes an hour takes a month without making any mechanical changes requires some clever hacks. [Josh] decided to use an Arduino to send digital pulses to the quartz movement to advance the minute hand, rather than let it run free. Two pulses a day would be perfect for making a 30-day month fit into a 60-minute hour, but that only works for four months out of the year. [Josh]’s solution was to mark the first 28 even-numbered minutes, cram 29, 30, and 31 into the last four minutes of the hour, and sort the details out in code.

As for the low-power mods, there’s some cool wizardry involved with that, like flashing the Arduino Pro Mini with a new bootloader that reduces the clock speed to 1 MHz. This allows the microcontroller and RTC module to run from the clock movement’s 1.5 V AA battery. [Josh] estimates a current draw of about 6 μA per day, which works out to about 50 years from a single cell. That’s to be taken with a huge grain of salt, of course, but we expect the battery will last a long, long time.

[Josh] built this clock as part of the Low-Power Challenge contest, which wrapped up this week. We’re looking forward to the results of the contest — good luck to all the entrants!

This Week In Security: USB Boom! Acropalypse, And A Bitcoin Heist

March 24, 2023 by Jonathan Bennett 4 Comments

We’ve covered a lot of sketchy USB devices over the years. And surely you know by now, if you find a USB drive, don’t plug it in to your computer. There’s more that could go wrong than just a malicious executable. We’ve covered creative and destructive ideas here on Hackaday, from creative firmware to capacitors that fry a machine when plugged in. But what happened to a handful of Ecuadorian journalists was quite the surprise. These drives went out with a bang.

That is, they literally exploded. The drives each reportedly contained a pellet of RDX, a popular explosive in use by militaries since the second World War. There have been five of these hyperactive USB devices located so far, and only one actually detonated. It seems that one only managed to trigger half of its RDX payload. Because of this, and the small overall size of a USB drive, the explosion was more comparable to a firecracker than a bomb. Continue reading “This Week In Security: USB Boom! Acropalypse, And A Bitcoin Heist” →

SheepShaver: A Cross-Platform Tool For Retro Enthusiasts

March 24, 2023 by Bryan Cockfield 20 Comments

The world of desktop computing has coalesced into what is essentially a duopoly, with Windows machines making up the bulk of the market share and Apple carving out a dedicated minority. This relatively stable state hasn’t always existed, though, as the computing scene even as late as the 90s was awash with all kinds of competing operating systems and various incompatible hardware. Amiga, Unix, OS/2, MacOS, NeXT, BeOS, as well as competing DOSes, were all on the table at various points.

If you’ve still got a box running one of these retro systems, SheepShaver might be able to help expand your software library. It’s not the sort of virtualization that we’re used to in the modern world, with an entire operating system running on a sanctioned-off part of your system. But SheepShaver does allow you to run software written for MacOS 7.5.2 thru 9.0.4 in a different environment. Unix and Linux are both supported, as well as Mac OS X, Windows NT, 2000, and XP, and the enigmatic BeOS. Certain configurations allow applications to run natively without any emulation at all, and there is plenty of hardware support built-in as well.

For anyone running retro hardware from the late 90s or early 00s, this could be just the ticket to get an application running that wasn’t ever supported on one of these machines. As for the name, it’s a play on another piece of software called ShapeShifter which brought a Mac-II emulator to the Amiga. SheepShaver has been around since the late 90s, too, so we’re surprised that we haven’t featured it before since it is such a powerful tool for cross-platform compatibility for computers of this era. Even if all you are hanging on to is an old BeBox.

CNC Intaglio-Esque Engraving

March 24, 2023 by Dave Rowntree 3 Comments

Intaglio is an ancient carving technique for adding details to a workpiece, by manually removing material from a surface with only basic hand tools. If enough material depth is removed, the resulting piece can be used as a stamp, as was the case with rings, used to stamp the wax seals of verified letters. [Nicolas Tranchant] works in the jewelry industry, and wondered if he could press a CNC engraving machine into service to engrave gemstones in a more time-efficient manner than the manual carving methods of old.

Engraving and machining generally work only if the tool you are using is mechanically harder than the material the workpiece is made from. In this case, this property is measured on the Mohs scale, which is a qualitative measurement of the ability of one (harder) material to scratch another. Diamond is the hardest known material on the Mohs scale and has a Mohs hardness of 10, so it can produce a scratch on the surface of say, Corundum — Mohs value 9 — but not the other way around.

[Nicolas] shows the results of using a diamond tip equipped CNC engraver on various gemstones typical of Intaglio work, such as Black Onyx, Malachite, and Amethyst with some details of the number of engraving passes needed and visual comparison to the same material treated to traditional carving.

Let’s be clear here, the traditional intaglio process produces deep grooves on the surface of the workpiece and the results are different from this simple multi-pass engraving method — but limiting the CNC machine to purely metal engraving duties seemed a tad wasteful. Now if they can only get a suitable machine for deeper engraving, then custom digitally engraved intaglio style seal rings could be seeing a comeback!

Intaglio isn’t just about jewelry of course, the technique has been used in the typesetting industry for centuries. But to bring this back into ours, here’s a little something about making a simple printing press.

Enormous Metal Sculpture Becomes An Antenna

March 23, 2023 by Bryan Cockfield 16 Comments

Those who have worked with high voltage know well enough that anything can be a conductor at high enough voltages. Similarly, amateur radio operators will jump at any chance to turn a random object into an antenna. Flag poles, gutters, and even streams of water can be turned into radiating elements for a transmitter, but the members of this amateur radio club were thinking a little bit bigger when they hooked up their transmitter to this giant sculpture.

For those who haven’t been to the Rochester Institute of Technology (RIT) in upstate New York, the enormous metal behemoth is not a subtle piece of artwork and sits right at the entrance to the university. It’s over 70 feet tall and made out of bronze and steel, a dream for any amateur radio operator. With the university’s permission and some help to ensure everyone’s safety during the operation, the group attached a feedline to the sculpture with a magnet, while the shield wire was attached to a ground rod nearby. A Yaesu FT-991 running on only 5 watts and transmitting in the 20-meter band was able to make contacts throughout much of the eastern United States with this setup.

This project actually started as an in-joke within the radio club, as reported by Reddit user [bbbbbthatsfivebees] who is a member. Eventually the joke became reality, as the sculpture is almost a perfect antenna for certain ham bands. Others in the comments noted that they might have better luck with lower frequency bands such as the 40-meter band or possibly the 60-meter band, due to the height of the structure. And, for those who are still wondering if you really can use a stream of water to transmit radio waves, it is indeed possible.