Cooking Eggs With Magnets In Motion

It’s probably always going to be easier to just find some dry wood and make a cooking fire, but if you’re ever in a real bind and just happen to have a bunch of magnets and a treadmill motor, this DIY induction cooktop could be your key to a hot breakfast.

For those not familiar with them, induction cooktops are a real thing. The idea stretches all the way back to the turn of the last century, and involves using a strong magnetic field to induce eddy currents in the metal of a cooking vessel. As [K&J Magnetics] explains, the eddy currents are induced in a conductor by changing magnetic fields nearby. The currents create their own magnetic field which opposes the magnetic field that created it. The resulting current flows through the conductor, heating it up. For their cooktop, they chose to spin a bunch of powerful neodymium magnets with alternating polarity using an old treadmill motor. The first try heated up enough to just barely cook an egg. Adding more magnets resulted in more heat, but the breakthrough came with a smaller pan. The video below shows the cooktop in action.

It’s worth noting that commercial induction cooktops use coils and a high-frequency alternating current instead or rotating magnets. They also are notoriously fussy about cookware, too. So, kudos to [K&J] for finding success with such an expedient build. As a next step, we’d love to see the permanent magnets replaced with small coils that can be electrically commutated, perhaps with a brushless motor controller. Continue reading “Cooking Eggs With Magnets In Motion”

SMORES Robot Finds Its Own Way To The Campfire

Robots that can dynamically reconfigure themselves to adapt to their environments offer a promising advantage over their less dynamic cousins. Researchers have been working through all the challenges of realizing that potential: hardware, software, and all the interactions in between. On the software end of the spectrum, a team at University of Pennsylvania’s ModLab has been working on a robot that can autonomously choose a configuration to best fit its task at hand.

We’ve recently done an overview of modular robots, and we noted that coordination and control are persistent challenges in this area. The robot in this particular demonstration is a hybrid: a fixed core module serving as central command, plus six of the lab’s dynamic SMORES-EP modules. The core module has a RGB+Depth camera for awareness of its environment. A separate downwards-looking camera watches SMORES modules for awareness of itself.

Combining that data using a mix of open robot research software and new machine specific code, this team’s creation autonomously navigates an unfamiliar test environment. While it can adapt to specific terrain challenges like a wood staircase, there are still limitations on situations it can handle. Kudos to the researchers for honestly showing and explaining how the robot can get stuck on a ground seam, instead of editing that gaffe out to cover it up.

While this robot isn’t the completely decentralized modular robot system some are aiming for, it would be a mistake to dismiss based on that criticism alone. At the very least, it is an instructive step on the journey offering a tradeoff that’s useful on its own merits. And perhaps this hybrid approach will find application with a modular robot close to our hearts: Dtto, the winner of our 2016 Hackaday Prize.

[via Science News]

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Cut Through The Noise, See Tiny Signals

An oscilloscope is a handy tool for measuring signals of all kinds, but it’s especially useful if you want to measure something with a periodic component. Modern oscilloscopes have all kinds of features built-in that allow you sample a wide range of signals in the hundreds of megahertz, and make finding and measuring your signal pretty easy, provided you know which buttons to push. There are some advanced oscilloscope methods that go beyond the built-in features of even the best oscilloscopes, and [AM] has a tutorial on one of them.

The method used here is called phase-senstitive detection, and allows tiny signals to be found within noise, even if the magnitude of the noise is hundreds of times greater than the signal itself. Normally this wouldn’t be possible, but by shifting the signal out of the DC range and giving it some frequency content, and then using a second channel on the oscilloscope to measure the frequency content of the source and triggering the oscilloscope on the second channel, the phase of the measured signal can be sifted out of the noise and shown clearly on the screen.

In [AM]’s example, he is measuring the intensity of a laser using a photodiode with a crude amplifier, but even with the amplifier it’s hard to see the signal in the noise. By adding a PWM-like signal to the power source of the laser and then syncing it up with the incoming signal from the photodiode, he can tease out the information he needs. It’s eally a fascinating concept, and if you fancy yourself a whiz with an oscilloscope this is really a tool you should have in your back pocket.  If you’re new to this equipment, we do have a primer on some oscilloscope basics, too.

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Code Review Lamp Subtly Reminds You To Help Your Fellow Developer

[Dimitris Platis] works in an environment with a peer review process for accepting code changes. Code reviews generally are a good thing. One downside though, is that a lack of responsiveness from other developers can result in a big hit to team’s development speed. It isn’t that other developers are unwilling to do the reviews, it’s more that individuals are often absorbed in their own work and notification emails are easily missed. There is also a bit of a “tragedy of the commons” vibe to the situation, where it’s easy to feel that someone else will surely attend to the situation, but often no one does. To combat this, [Dimitris] built this Code Review Lamp, a subtle notification that aims to prod reviewers into action.

The lamp is based on a ring of RGB LEDs and a Wemos D1 Mini board. The Wemos utilizes the popular ESP8266, so it’s easy to develop for. The LED ring and Wemos are tied together with a slick custom PCB. Mounting the LED ring on the top of the PCB and the Wemos on the bottom allows for easy powering via a USB cable while directing light upward.  The assembly is placed in a translucent 3D printed enclosure creating a pleasant diffuse light source.

Every developer gets a Code Review Lamp. The lamps automatically log in to the change management system to check whether anything is awaiting review. If a review is ready, the Lamp glows in a color specific to the individual developer. All this serves as a gentle but persistent reminder that someone’s work is being held up until a review is completed.

We love the way that the device has a clear purpose: it does its job without any unnecessary features or parts. It’s similar to this ESP8266 IoT Motion Sensor in that it has a single job to do, and focuses on it well.

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A Cow-Powered Human Centrifuge

Spoiler alert: group of fun-loving French folks build an animal-or-human-powered merry-go-round that spins fast enough to fling all takers into the lake (YouTube, embedded below). Actually, that’s basically it. The surprise is ruined, but you probably want to check out the video anyway, because it looks like a ton of fun.

Granted, you may not have a well-stocked metal shop or a team of oxen up by the lake wherever you live, but there are certainly details in the video that will survive in translation. Basically, the team took the axle off of a junked car, attached it to a pole in the middle of the lake, made a large wooden drive wheel, and wrapped an infinite length of rope around it.

[Charles] from [Mad Cow] wrote us that there was about a 10:1 ratio between the drive wheel and the arms of the people-flinger. So if the cattle were pulling at 3 km/h, the human angular velocity was a brisk 30 km/h! Then it’s just a matter of convincing a team of cows, or a team of soccer players (?), to put their backs into it.

The [Mad Cow] crew seems to have more than their fair share of engineering dangerous fun up at their summer hideaway: check out their human crossbow that we featured a few years back.

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This Cup Holder Crystal Ball Tells Your MPG Future

Hybrid vehicles, which combine an eco-friendly electric motor with a gasoline engine for extended range, are becoming more and more common. They’re a transitional technology that delivers most of the advantages of pure electric vehicles, but without the “scary” elements of electric vehicle ownership which are still foreign to consumers such as installing a charger in their home. But one element which hybrids are still lacking is a good method for informing the driver whether they’re running on petroleum or lithium; a way to check at a glance how “green” their driving really is.

[Ben Kolin] and his daughter [Alyssa] have come up with a clever hack that allows retrofitting existing hybrid vehicles with an extremely easy to understand indicator of real-time vehicle efficiency. No confusing graphics or arcade-style bleeps and bloops, just a color-changing orb which lives in the cup holder. An evolved version which takes the form of a smaller “dome light” that sits on the top of the dashboard could be a compelling aftermarket accessory for the hybrid market.

The device, which they are calling the ecOrb, relies on an interesting quirk of hybrid vehicles. The OBD II interface, which is used for diagnostics on modern vehicles, apparently only shows the RPM for the gasoline engine in a hybrid. So if the car is in motion but the OBD port is reporting 0 RPM, the vehicle must be running under electric power.

With a Bluetooth OBD adapter plugged into the car, all [Ben] and [Alyssa] needed was an Arduino Nano clone with a HC-05 module to read the current propulsion mode in real-time. With some fairly simple conditional logic they’re able to control the color of an RGB LED based on what the vehicle is doing: green for driving on electric power, purple for gas power, and red for when the gas engine is at idle (the worst case scenario for a hybrid).

Check out our previous coverage of OBD hacking on the Cadillac ELR hybrid if you’re looking to learn more about what’s possible with this rapidly developing class of vehicle

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The Portable, Digital, Visual Theremin

The theremin is, for some reason, what people think of first when they think of electronic musical instruments. Maybe that’s because it was arguably the first purely electronic musical instrument, or because there’s no mechanical analog to something that makes sound simply by waving your hand over it. This project takes that idea and cranks it up to eleven. It’s a portable synthesizer that’s controlled by IR reflectors. Just wave your hand in front of it, and that’s what pitch is going to sound.

The audio hardware for this synth is, like so many winners in the Musical Instrument Challenge in this year’s Hackaday Prize, based on the Teensy and its incredible Audio library. The code consists of two oscillators and a pink noise generator. Pressing down button one activates the oscillators, and the frequency is determined by the IR sensor. Button two cycles through various waveforms, while the third and fourth buttons shift the octaves up and down. The output is I2S, and from there everything is out to an amplifier and speaker.

Of course, it’s really not a musical instrument unless it looks cool, and that’s where this project is really great. It’s a fully 3D printed enclosure that actually looks good. There’s an 8×8 LED array to display the current waveform, and this is something that could actually be a product instead of a project. It’s a great synth, and we’re happy to have it in the running for the Hackaday Prize.

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