The Linux Throwie: Powering A Linux Server With A 0.3W Solar Panel

Have you ever had one of those moments, when you’re rummaging through your spare parts heap, and have a rather bizarre project idea that you can’t quite get out of your head? You know, the ones that have no clear use, but simply demand to be born, of glass and steel and silicon?

This time, the stubborn idea in question was sort of like a solar-rechargeable LED throwie, but instead of a blinking light, it has a fully cloud-accessible embedded Linux server in the form of a Raspberry Pi 3 Model B+. Your choice of embedded Linux board should work — I just happen to have a lot of these due to a shipping error.

There were two main challenges here: First, it would have to combine the smallest practical combination of solar panel, power supply, and Li-ion cell that could run the Raspberry Pi. Second, we’ll need to remotely activate and access the Pi regardless of where it is, as well as be able to connect it to WiFi without direct physical access. In this article we’ll be dealing with the first set of problems — stay tuned for the rest.

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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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