A pile of red Swiss Army knives, probably collected by TSA.

Introducing The Swiss Army… Tool?

May 9, 2024 by Kristina Panos 152 Comments

You’ve probably used one for everything from opening packages to stripping wires in a pinch (because you know better than to use your teeth). We’re talking about the blade of the iconic Swiss Army knife. And while there are many different models out there, they all feature at least one knife among their utensils. Until now.

Citing pressure due to the increase in worldwide knife violence, the company announced that they’ll be releasing a new range of tools without blades. Carl Elsner, fourth-generation CEO of Swiss Army knife maker Victorinox, is also concerned about increasing regulations surrounding knives at sporting events and other activities. And he has a point: according to the UN’s Global Study on Homicide 2023 (PDF), 30% of European homicides were committed with some type of sharp object.

In an interview with The Guardian, Elsner spoke of creating more specialized tools, such as one for cyclists, who don’t necessarily need a blade. He also mentioned that Victorinox have a tool specifically for golfers, but we’d like to point out that it features, among other things, a knife.

It’s going to be a long time before people stop assuming that the skinny red thing in your pocket contains a knife, especially at the airport. What TSA agent is going to take the time to check out your tool? They’re going to chuck it in the bucket with the rest of them. Would you consider buying a blade-less multi-tool? Let us know in the comments.

Don’t have much need for a knife? Here’s a bench tool that has it all.

(Main and thumbnail photos via Unsplash)

Much Faster Cold Brew Through Cavitation

May 8, 2024 by Kristina Panos 27 Comments

Some coffee snobs might call this sacrilege. Cold brew is supposed to take a long time — that’s part of how it gets its characteristic smoothness. But a group of engineers from the University of New South Wales (UNSW Sydney) have figured out a way to cut the time down from several hours to a mere three minutes, using ultrasonic waves.

Typically, the cold brew coffee process takes between 12 and 24 hours. Enough time to steep the grounds and extract the flavors without the benefit of hot water. This is how it differs from iced coffee, which is brewed hot and poured over ice.

Interestingly, the UNSW Sydney engineers’ process uses a typical prosumer-grade espresso machine and involves blasting the portafilter with a transducer and a horn. This transforms the coffee basket into a sonoreactor. Sound waves at a frequency of 38.8 kHz are injected at multiple points through the walls, generating acoustic cavitation within. You can read all about it in Ultrasonics Sonochemistry.

That’s not even the most exciting part. The study found that this arrangement is capable of doubling both the extraction yield and caffeine concentration, compared with non-soundblasted samples. The team sent samples of the coffee off to be evaluated on aroma, texture, flavor, and aftertaste. Although the one-minute extraction samples received similar ratings to a 24-hour brew in terms of flavor and aftertaste, they lacked the intensity and dark chocolate aroma of the longer brew. But the three-minute extraction samples scored quite highly in all areas, suggesting that the average cold brew drinker wouldn’t be able to tell the difference.

Would you like to roast your own beans at home? You can use a popcorn popper, but you might get tired of semi-uneven roasts and upgrade to a DIY wobble disk roaster.

Continue reading “Much Faster Cold Brew Through Cavitation” →

A capacitive touch MIDI instrument that doubles as a bookmark.

MIDI Bookmark Marks The Spot Where Work And Play Intersect

May 6, 2024 by Kristina Panos 2 Comments

Have you ever wanted to take a break from reading or studying to just rock out for a few blissful minutes? If you’re anything like us, you like to rock out most of the time and take the occasional break to do your reading. Either way, you really can’t go wrong with this MIDI bookmark from [Misfit Maker].

This slick little bookmark may look 3D printed, but it’s all carefully-cut foam board in two thicknesses. Even the keys are made foam board — they’re just wrapped in carbon fiber so they look extra cool.

Underneath that carbon fiber is a layer of aluminium tape to make them capacitive. [Misfit Maker] recommends using copper tape instead because it allows for wires to be soldered directly to the keys.

The brains of this beauty is in the form of an ESP32 which is controlling an MPR-121 capacitive touch sensor. If you’d like to make one of these for yourself, there are plenty of helpful GIFs embedded in the thorough write-up. Be sure to check out the brief demo after the break.

If you want to easily MIDI-fy something and use touch inputs, you can’t really go wrong with the Raspberry Pi Pico, which does capacitive touch natively. Check out this MIDI kalmiba to learn more.

Continue reading “MIDI Bookmark Marks The Spot Where Work And Play Intersect” →

A beehive sits on bricks with an outdoor-rated box full of electronics to monitor the hive.

Hive Monitor Is The Bee’s Knees

May 5, 2024 by Kristina Panos 11 Comments

Beekeeping is quite the rewarding hobby. There’s delicious honey and useful wax to be had, plus you get the honor of knowing that you’re helping to keep the bee population surviving and thriving. [Ben Brooks] likes to keep tabs on the hive, but doesn’t like the idea of opening it up more often than necessary. After a couple of beekeeping rodeos, [Ben] decided to build his own tracker to get reports on the health and the activity of the hive through Home Assistant.

This hive tracker features a light sensor, a temperature sensor, and three strain gauges to measure the weight. There would be four, but a mouse decided to take a bite of the wires in the most nightmarish place to repair.

Everything runs off of an ESP32, and there’s an external antenna involved because the hive is nearly out of Wi-Fi range. The strain gauges are the affordable bathroom-scale type, and [Ben] has extras for if and when the number of hives goes up.

We like the combination of hard work and simplicity going on here — [Ben] milled and drilled the PCB himself, and used phone plugs to connect the temperature and weight sensors. Unfortunately, the plugs make the strain gauges a little finicky, so [Ben] says he would probably use screw terminals next time, or might be soldering the wires sooner rather than later. Consider this one a work in progress, and keep watching for updates as [Ben] works out the kinks.

Interested in beekeeping, but don’t want to build a traditional hive? Check out this beehive in a bottle.

A DIY coffee roaster with part callouts.

Follow The Red Ball Wobble Disk Roaster To Coffee Excellence

May 3, 2024 by Kristina Panos 9 Comments

If you’ve never considered roasting your own coffee at home, you may be surprised to learn that it can be done in a few minutes with a regular popcorn popper and not much else. After all, you only really need two things to roast coffee: heat, and constant agitation to distribute that heat evenly. While the popcorn popper provides both, it’s easy to end up with semi-uneven roasts, probably because the beans are mostly just spinning around and not being tossed as well as they could be. Eventually, one might want a more advanced machine, and that’s where something like [Larry Cotton]’s latest wobble disk roaster can step in.

For starters, this machine roasts more beans than the average popcorn popper in a single throw — the maximum is 350g, or just over three-quarters of a full pound, which is way more than the average popcorn machine will hold. It essentially consists of a heat gun pointed upwards at a sieve full of green coffee beans that are being constantly pushed around by a motorized wobbling disk. As the heat blows, the large metal disk does figure eights through the beans, keeping the heat nice and even. So where does the red ball come in? It’s at the bottom, keeping the flying bean skins (chaff) from entering the heat gun’s fan motor.

Toward the end of the short video after the break, you’ll see a diagram showing all the parts of this roaster. If that’s not enough for you, here’s a build guide for a previous wobble disk roaster (PDF) that should be quite helpful in building either version.

If you want to see some of Larry’s previous machines, we’ve got ’em. And then you can let Hackaday Editor-in-Chief [Elliot Williams] tell you all about roasting at home.

Continue reading “Follow The Red Ball Wobble Disk Roaster To Coffee Excellence” →

Hackaday Podcast Episode 269: 3D Printed Flexure Whegs, El Cheapo Bullet Time, And A DIY Cell Phone Sniffer

May 3, 2024 by Kristina Panos 1 Comment

This week, it was Kristina’s turn in the hot seat with Editor-in-Chief Elliot Williams. First up in the news — the results are in for the 2024 Home Sweet Home Automation contest! First and second place went to some really gnarly, well-documented hacks, and third went to the cutest pill-dispensing robot you’ll probably see before you hit the retirement home. Which was your favorite? Let us know in the comments.

A collection of multimeter probe extenders from Radio Shack. — Kristina’s lil’ wallet of extender probes, courtesy of Radio Shack.

Then it’s on to What’s That Sound. Kristina failed once again, but you will probably fare differently. Can you get it? Can you figure it out? Can you guess what’s making that sound? If you can, and your number comes up, you get a special Hackaday Podcast t-shirt.

Then it’s on to the hacks, beginning with a DIY cell phone sniffer and a pen that changed the world. Then we talk bullet time on a budget, the beautiful marriage of 3D printing and LEGO, and, oh yes, flexure whegs. Finally, we get the lowdown on extender probes, and posit why it’s hard to set up time zones on the Moon, relatively speaking.

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!

Download and savor at your leisure.

Continue reading “Hackaday Podcast Episode 269: 3D Printed Flexure Whegs, El Cheapo Bullet Time, And A DIY Cell Phone Sniffer” →

A small gauge showing power generated by a house's solar panels.

Cute Solar Power Gauge Brightens The Day

May 2, 2024 by Kristina Panos 5 Comments

What’s the first thing you want after installing solar? All the sunshine you can get, of course. Especially if you did it in the wintertime. And what would be more fun than monitoring your power generation, especially leading up to the equinox, or start of spring? Probably not much, especially if you built a cute solar power gauge like [Ben] did to keep him from obsessively checking his phone.

At the heart of this build is the affordable Seeed Xiao ESP32C3, which controls an equally cost-effective automotive stepper via an L293D H-bridge driver. Then it was just a matter of hooking it into Home Assistant. As power is generated by the solar system, the cute little sun on the gauge rises and shows the kilowattage gained.

Unfortunately there’s no real data sheet for the stepper, so [Ben] opted to use the 5 V from the USB that’s powering the ESP32. However, it seems like this might not be enough power because the gauge appears to drift a bit. To fix this, [Ben] runs the stepper_init script twice a day, which cranks the dials all the way forward then all the way backward before settling on the last known value.

Are you interested in solar? Here’s how you can build a small power system.