Cooking Eggs With Magnets In Motion

November 2, 2018 by 71 Comments

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” →

Vibrosight Hears When You Are Sleeping. It Knows When You’re Awake.

October 22, 2018 by 16 Comments

No matter how excited you are to dive headfirst into the “Internet of Things”, you’ve got to admit that the effort and expense of going full-on Jetsons is a bit off-putting. To smarten up your home you’ve generally got to buy all new products (and hope they’re all compatible) or stick janky after-market sensors on the gear you’ve already got (and still hope they’re all compatible). But what if there was a cheap and easy way to keep tabs on all your existing stuff? The answer may lie in Cold War era surveillance technology.

As if the IoT wasn’t already Orwellian enough, Vibrosight is a project that leverages a classic KGB spy trick to keep tabs on what’s going on inside your home. Developed by [Yang Zhang], [Gierad Laput] and [Chris Harrison], the project uses retro-reflective stickers and a scanning laser to detect vibrations over a wide area. With this optical “stethoscope”, the system can glean all kinds of information; from how long you’ve been cooking something in the microwave to whether or not you washed your hands.

The project takes its inspiration from the optical eavesdropping system developed by Léon Theremin in the late 1940’s. By bouncing a beam of light off of a window, Theremin’s gadget was able to detect what people inside the room were saying from a distance. The same idea is applied here, except now it uses an automated laser scanner and machine learning to turn detected vibrations into useful information that can be plugged into a home automation system.

For Vibrosight to “listen” to objects, the user needs to place retro-reflective tags on whatever they want to include in the system. The laser will periodically scan around the room looking for these tags. Once the laser finds a new tag, will add it to a running list of targets to keeps an eye on. From there Vibrosight is able to take careful vibration measurements which can provide all sorts of information. In the video after the break, Vibrosight is shown differentiating between walking, jogging, and running on a treadmill and determining what kind of hand tools are being used on a workbench. The team even envisions a future where Vibrosight-ready devices would “hum” their IP address or other identifying information to make device setup easier.

If all this talk of remote espionage at a distance has caught your interest, we’ve covered Theremin’s unique surveillance creations in the past, and even a way to jam them if you’re trying to stay under the radar.

Continue reading “Vibrosight Hears When You Are Sleeping. It Knows When You’re Awake.” →

Build Your Own Rowing Machine, Now With Digital Readout!

July 4, 2018 by 12 Comments

An ergometer is a fancy fitness word for a rowing machine, a device which can be used to work out the muscles used in rowing. It’s an excellent cardio workout that can also build upper body strength, and resistance can be varied depending on the individual’s fitness goals. But perhaps you need to measure your workout to see your progress – in which case, [Dave]’s instrumentation package might be right up your alley.

The basic mechanical build involves a wooden frame, fitted with a rowing setup built around a modified bicycle wheel. The wheel has vanes attached, made of what appears to be cut sections of PVC pipe. These act essentially as dampers, using the air to create the resistance for the rower to work against.

The wheel is instrumented with a chopper wheel and an IR optical switch, which measures the rotational speed of the wheel during rowing. This signal is fed into an ATMega328 which runs the calculations on the rower’s performance. It’s all fed to a Nokia 5110 screen for display, which makes a lovely throwback for those that remember the brick fondly.

[Dave] touches not only on the electronic aspects of the build, but also does an excellent job of breaking down the mathematics behind rowing performance. It’s a great resource that builds on top of the excellent work by the OpenErgo project.

If we’ve whet your thirst for exercise machine hacks, you’d better check out this treadmill to belt grinder mod.

Christal Gordon: Sensors, Fusion, And Neurobiology

December 12, 2017 by 3 Comments

Some things don’t sound like they should go together, but they do. Peanut butter and chocolate. Twinkies and deep frying. Bacon and maple syrup. Sometimes mixing things up can produce great results. [Dr. Christal Gordon’s] expertise falls into that category. She’s an electrical engineer, but she also studies neuroscience. This can lead to some interesting intellectual Reese’s peanut butter cups.

At the 2017 Hackaday Superconference, [Christal] spoke about sensor fusion. If you’ve done systems that have multiple sensors, you’ve probably run into that before even if you didn’t call it that. However, [Christal] brings the perspective of how biological systems fuse sensor data contrasted to how electronic systems perform similar tasks. You can see a video replay of her talk in the video below.

Continue reading “Christal Gordon: Sensors, Fusion, And Neurobiology” →

Ok Google. Navigate To The International Space Station

July 23, 2017 by 18 Comments

If you’d have asked most people a few decades ago if they wanted a picture of every street address in the world, they would have probably looked at you like you were crazy. But turns out that Google Street View is handy for several reasons. Sure, it is easy to check out the neighborhood around that cheap hotel before you book. But it is also a great way to visit places virtually. Now one of those places is the International Space Station (ISS).

[Thomas Pesquet] in a true hack used bungee cords and existing cameras to take panoramas of all 15 ISS modules. Google did their magic, and you can enjoy the results. You can also see a video on how it was all done, below.

Continue reading “Ok Google. Navigate To The International Space Station” →

Exoskeleton Aims To Prevent Falls For Seniors

May 17, 2017 by 12 Comments

When we think of exoskeletons, we tend to think along comic book lines: mechanical suits bestowing superhero strength upon the villain. But perhaps more practical uses for exoskeletons exists: restoring the ability to walk, for instance, or as in the case of these exoskeleton shorts, preventing hip fractures by detecting and correcting falls before they happen.

Falls and the debilitating injuries that can result are a cruel fact of life for the elderly, and anything that can potentially mitigate them could be a huge boon to public health. Falls often boil down to loss of balance from slipping, whether it be a loose rug, a patch of ice, or even the proverbial banana peel. The “Active Pelvic Orthosis” developed by [Vito Monaco] and colleagues seeks to sense slips and correct them by applying the correct torque to the hip joints. Looking a little bulky in their prototype form and still tethered to an external computer, the shorts have motors with harmonic drives and angle sensors for each hip, plus accelerometers to detect the kinematic signature of a slip. The researchers discovered that forcing the leg that slipped forward while driving the stable leg back helped reduce the possibility of a fall. The video below shows the shorts in action preventing falls on a slip-inducing treadmill.

At the Hackaday Unconference in Pasadena, we heard from [Raul Ocampo] on his idea for autonomous robots to catch falling seniors. Perhaps wearing the robot will end up being a better idea.

Continue reading “Exoskeleton Aims To Prevent Falls For Seniors” →

“Look Ma, No Gyros!”: A Self-Balancing Mechanical Velociraptor

May 7, 2017 by 22 Comments

You’ve got to walk before you can run, right? Perhaps not, if this bipedal dino-like running robot is any indication.

Officially dubbed a “Planar Elliptical Runner,” the bot is a test platform for bipedal locomotion from the Institute for Human and Machine Cognition. Taking inspiration from the gait of an ostrich — we think it looks more like a T. rex or velociraptor, but same difference — [Jerry Pratt]’s team at IHMC have built something pretty remarkable. Contrary to all the bipedal and quadrupedal robots we’ve seen, like Boston Dynamics’ Big Dog and PETMAN, which all fairly bristle with sensors and actuators, the PER is very stripped down.

A single motor runs the entire drive chain using linkages that will look familiar to anyone who has taken an elliptical trainer apart, and there’s not a computer or sensor on board. The PER keeps its balance by what the team calls “reactive resilience”: torsion springs between the drive sprocket and cranks automatically modulate the power to both the landing leg and the swing leg to confer stability during a run. The video below shows this well if you single-frame it starting at 2:03; note the variable angles of the crank arms as the robot works through its stride.

The treadmill tests are constrained by a couple of plastic sheets, but the next version will run free. It’s not clear yet how directional control will be achieved, not is it obvious how the PER will be able to stop running and keep its balance. But it’s an interesting advance in locomotion and we look forward to seeing what IHMC’s next trick will be.

Continue reading ““Look Ma, No Gyros!”: A Self-Balancing Mechanical Velociraptor” →