2024 Business Card Challenge: CardTunes Bluetooth Speaker

July 20, 2024 by Donald Papp 8 Comments

A business card form factor can be quite limiting, but that didn’t stop [Schwimmflugel] from creating CardTunes, an ESP32-based Bluetooth audio speaker that tried something innovative to deliver the output.

What’s very interesting about this design is the speaker itself. [Schwimmflugel] aimed to create a speaker out of two coils made from flexible circuit board material, driving them with opposite polarities to create a thin speaker without the need for a permanent magnet.

The concept is sound, but in practice, performance was poor. One could identify the song being played, but only if holding the speaker up to one’s ear. The output was improved considerably with the addition of a small permanent magnet behind the card, but of course this compromised the original vision.

Even though the concept of making a speaker from two flexible PCB panel coils had only mixed success, we love seeing this kind of effort and there’s a lot to learn from the results. Not to mention that it’s frankly fantastic to even have a Bluetooth speaker on a business card in the first place.

The 2024 Business Card Challenge is over, but judging by all the incredible entries we received, we’re thinking it probably won’t be too long before we come up with another sized-constrained challenge.

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Sealed Packs Of Pokémon Cards Give Up Their Secrets Without Opening Them

July 20, 2024 by Donald Papp 32 Comments

[Ahron Wayne] succeeded in something he’s been trying to accomplish for some time: figuring out what’s inside a sealed Pokémon card packet without opening it. There’s a catch, however. It took buying an X-ray CT scanner off eBay, refurbishing and calibrating it, then putting a load of work into testing and scanning techniques. Then finally combining the data with machine learning in order to make useful decisions. It’s a load of work but [Ahron] succeeded by developing some genuinely novel techniques.

While using an X-ray machine to peek inside a sealed package seems conceptually straightforward, there are in fact all kinds of challenges in actually pulling it off. There’s loads of noise. So much that the resulting images give a human eyeball very little to work with. Luckily, there are also some things that make the job a little easier.

For example, it’s not actually necessary to image an entire card in order to positively identify it. Teasing out the individual features such as a fist, a tentacle, or a symbol are all useful to eliminate possibilities. Interestingly, as a side effect the system can easily spot counterfeit cards; the scans show up completely different.

When we first covered [Ahron]’s fascinating journey of bringing CT scanners back to life, he was able to scan cards but made it clear he wasn’t able to scan sealed packages. We’re delighted that he ultimately succeeded, and also documented the process. Check it out in the video below.

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Robot Seeks And Sucks Up Cigarette Butts, With Its Feet

July 20, 2024 by Donald Papp 29 Comments

It would be better if humans didn’t toss cigarette butts on the ground in the first place, but change always takes longer than we think it should. In the meantime, researchers at the Italian Institute of Technology have used the problem as an opportunity to explore what seems to be a novel approach: attaching vacuum pickups to a robot’s feet, therefore removing the need for separate effectors.

VERO (Vacuum-cleaner Equipped RObot) is a robotic dog with a vacuum cleaner “backpack” and four hoses, one going down each leg. A vision system detects a cigarette butt, then ensures the robot plants a foot next to it, sucking it up. The research paper has more details, but the video embedded below gives an excellent overview.

While VERO needs to think carefully about route planning, using the legs as effectors is very efficient. Being a legged robot, VERO can navigate all kinds of real-world environments — including stairs — which is important because cigarette butts know no bounds.

Also, using the legs as effectors means there is no need for the robot to stop and wait while a separate device (like an arm with a vacuum pickup) picks up the trash. By simply planting a foot next to a detected cigarette butt, VERO combines locomotion with pickup.

It’s fascinating to see how the Mini Cheetah design has really become mainstream to the point that these robots are available off-the-shelf, and it’s even cooler to see them put to use. After all, robots tackling trash is a good way to leverage machines that can focus on specific jobs, even if they aren’t super fast at it.

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Watch This RC Jet Thrust System Dance

July 19, 2024 by Donald Papp 7 Comments

An EDF (electric duct fan) is a motor that basically functions as a jet engine for RC aircraft. They’re built for speed, but to improve maneuverability (and because it’s super cool) [johnbecker31] designed a 3D-printable method of adjusting the EDF’s thrust on demand.

Before 3D printers were common, making something like this would have been much more work.

The folks at Flite Test released a video in which they built [john]’s design into a squat tester jet that adjusts thrust in sync with the aircraft’s control surfaces, as you can see in the header image above. Speaking of control surfaces, you may notice that test aircraft lacks a rudder. That function is taken over by changing the EDF’s thrust, although it still has ailerons that move in sync with the thrust system.

EDF-powered aircraft weren’t really feasible in the RC scene until modern brushless electric motors combined with the power density of lithium-ion cells changed all that. And with electronics driving so much, and technology like 3D printers making one-off hardware accessible to all, the RC scene continues to be fertile ground for all sorts of fascinating experimentation. Whether it’s slapping an afterburner on an EDF or putting an actual micro jet engine on an RC car.

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Giving People An Owl-like Visual Field Via VR Feels Surprisingly Natural

July 16, 2024 by Donald Papp 29 Comments

We love hearing about a good experiment, and here’s a pretty neat one: researchers used a VR headset, an off-the-shelf VR360 camera, and some custom software to glue them together. The result? Owl-Vision squashes a full 360° of un-distorted horizontal visual perception into 90° of neck travel to either side. One can see all around oneself, without needing to physically turn one’s head any further than is natural.

It’s still a work in progress, and accessing the paper currently doesn’t have a free option, but the demonstration video at that link (also embedded below) gives a solid overview of what’s going on.

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Newly Completed Overly-Complex Clock Synchronizes Multiple Mechanisms

July 11, 2024 by Donald Papp 1 Comment

Some time ago [Kelton] was working on a clock inspired by Rube Goldberg contraptions. It uses only a single motor, and he’s proud to now show off the finished product (video, embedded below.)

The clock shows hours on the left, and minutes on the right. Every sixty minutes the clock drops a marble. That marble kicks off a series of visually-satisfying operations that culminate in advancing the hour. Then everything resets, and it continues for as long as it has power.

The hour oscillates in a very satisfying manner as it locks in.

At the top of each hour, the minute hand tips a marble with a gravity cam. That marble runs down a track gaining enough momentum to flip a kicker, and a short series of falling dominoes builds enough force to tip and trigger the spring-loaded ratchet that locks in a new hour. You can skip directly to 2:09 if you just want to listen to [Kelton] explain the whole operation from beginning to end.

We think it’s very interesting to note that this clock’s complexity is, if anything, understated. Each of the mechanisms involved must individually reset by their own separate mechanisms, each of which are as intriguing as their showier counterparts, and we’re sure they were every bit as difficult to get just right. And of course, it’s all driven by a single motor.

You may recall the promising start this clock project was off to and we’re delighted to see it come to completion, especially considering its complexity. Not every project sees completion, and fewer still get a version two, but that’s okay. What really floats our boat is seeing the process and details as well as hearing about what worked and what didn’t. We’re glad this clock reached the finish line, but even if something doesn’t work out, there’s always something to learn.

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Making EV Motors, And Breaking Up With Rare Earth Elements

July 9, 2024 by Donald Papp 85 Comments

Rare earth elements are used to produce magnets with very high strength that also strongly resist demagnetization, their performance is key to modern motors such as those in electric vehicles (EVs). The stronger the magnets, the lighter and more efficient a motor can be. So what exactly does it take to break up with rare earths?

Rare earth elements (REEs) are actually abundant in the Earth’s crust, technically speaking. The problem is they are found in very low concentrations, and inconveniently mixed with other elements when found. Huge amounts of ore are required to extract useful quantities, which requires substantial industrial processing. The processes involved are ecologically harmful and result in large amounts of toxic waste.

Moving away from rare earth magnets in EV motors would bring a lot of benefits, but poses challenges. There are two basic approaches: optimize a motor for non-rare-earth magnets (such as iron nitrides), or do away with permanent magnets entirely in favor of electromagnets (pictured above). There are significant engineering challenges to both approaches, and it’s difficult to say which will be best in the end. But research and prototypes are making it increasingly clear that effective REE-free motors are perfectly feasible. Breaking up with REEs and their toxic heritage would be much easier when their main benefit — technological performance — gets taken off the table as a unique advantage.