Tiny Robot Clings To Leaves With Static Electricity

Flying is an energy-intensive activity. The birds and the bees don’t hover around incessantly like your little sister’s quadcopter. They flit to and fro, perching on branches and leaves while they plan their next move. Sure, a quadcopter can land on the ground, but then it has to spend more energy getting back to altitude. Researchers at Harvard decided to try to develop flying robots that can perch on various surfaces like insects can.

Perching on surfaces happens electrostatically. The team used an electrode patch with a foam mounting to the robot. This allows the patch to make contact with surfaces easily even if the approach is a few degrees off. This is particularly important for a tiny robot that is easily affected by even the slightest air draft. The robots were designed to be as light as possible — just 84mg — as the electrostatic force is not particularly strong.

It’s estimated that perching electrostatically for a robot of this size uses approximately 1000 times less power than during flight. This would be of great use for surveillance robots that could take up a vantage point at altitude without having to continually expend a great deal of energy to stay airborne. The abstract of the research paper notes that this method of perching was successful on wood, glass, and a leaf. It appears testing was done with tethers; it would be interesting to see if this technique would be powerful enough for a robot that carries its own power source. Makes us wonder if we ever ended up with tiny flyers that recharge from power lines?

We’re seeing more tiny flying robots every day now – the IMAV 2016 competition was a great example of the current state of the art.

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How To Sharpen Your Woodworking Tools On A Budget

Wood may seem like a soft, weak material if you’re used to working with steel, but to do good work, you’ll quickly learn you need your tools sharp. Buying and maintaining a good set of tools can be expensive for the home gamer, so [shopbuilt] put together an Instructable on how to sharpen your woodworking tools on a budget.

The trick is to use sandpaper. It’s a good quality abrasive material and is readily available. You’ll want a selection of different grits – low grits to get started, higher grits when finishing. The reason this is cheaper is that you can get a selection of 5-10 different sandpapers for under $20. Getting even a couple of decent sharpening stones wouldn’t be possible at that price. In the long run, they’ll last longer but this is a budget option we’re talking about.

Obviously you can’t just sharpen something with sandpaper – [shopbuilt] suggests mounting the paper to the flattest surface you can find. The use of a tempered glass panel from a fridge shelf is, in our mind, an inspired choice here. 3D printer enthusiasts have been using similar techniques for heated beds for the best part of a decade now.

We love woodworking here at Hackaday, so get your feet wet with these woodworking basics for the hardware hacker.

Woodworking Basics for the Hardware Hacker

Hackaday is primarily a place for electronics hackers, but that’s not to say that we don’t see a fair number of projects where woodworking plays a key role. Magic mirror builds come to mind, as do restorations of antique radios, arcade machines built into coffee tables, and small cases for all manner of electronic and mechanical gadgets. In some of these projects, the woodworking really shines and makes the finished project pop. In others — well, let’s just say that some woodwork looks good from far, but is far from good.

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Foldable Dymaxion Globe

Some time back, we posted about [Gavin]’s laser-cut/3D printed Dymaxion Globe — if you haven’t read about it yet, you should check it out. [noniq] loved the idea, and like a true hacker, built and shared an improved Foldable Dymaxion Globe. It can snap together to form an icosahedron globe, or it can be laid flat to form a map.

Duct tape, stoppers and magnet holders
Duct tape, stoppers and magnet holders

Like the original, [noniq]’s version is laser cut and engraved, and uses some 3D printed parts. But it does away with the fasteners (that’s 60 pairs of nuts and bolts), and instead uses neodymium magnets to make all the triangle pieces snap together to form the icosahedron globe. The hinges are simply some pieces of gaffer-tape.

This design improvement creates a cleaner globe and also addresses some of the concerns posted in the comments of the earlier build. The design files are available for download on [noniq]’s blog — you need to 3D print some magnet holders and stopper plates, and laser cut the 20 triangle tiles. The stopper plates help ensure that the angle between tiles when it is put together is limited to 138 degrees, making it easier to assemble the globe.

Check out the video after the break to hear the satisfying “thunk” of neodymium magnets snapping together.

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Laser Cutting a Wooden Dymaxion Globe

Everyone knows that globes are cool — what else would you use as the centerpiece of your library/study? But, sadly, making your own isn’t a simple process. Even if you had a large (preferably hollow) sphere to work with, you’d still have to devise a clever way of printing the map in sections that can be glued to the curved surface. Wouldn’t it be easier if you could just laser cut flat sections, and assemble them to form a faceted “globe?”

Well, it is, and you can! Because, [Gavin] over at tinkerings.org (a Hackaday favorite) has created the files to do just that! This map projection, originally designed by the very interesting Buckminster Fuller, is designed to be either laid flat or three-dimensionally on an icosahedron (a 20-sided polyhedron). That makes it perfect for laser cutting, as each of the 20 faces can be cut from flat stock.

600px-fuller_projection_with_tissot27s_indicatrix_of_deformation

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Wooden Puzzle Book Will Twist and Dazzle Your Brain

In what might be one of the coolest applications of laser cutting, joinery, puzzles, writing, and bookbinding, [Brady Whitney] has created the Codex Silenda — a literal puzzle book of magnificent proportions.

[Whitney] had originally conceived the idea of the Codex for his senior thesis research project at Iowa State University, and the result is something for almost everyone. On each of the Codex’s five pages lies a mechanical puzzle that must be solved to progress to the next, while an accompanying text weaves a story as you do so. These intricate pages were designed in SolidWorks and painstakingly assembled from laser cut wood. Breaking the fourth wall of storytelling by engaging the reader directly in uncovering the book’s mysteries is a unique feat, and it looks gorgeous to boot.

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Maslow Brings The Wall Plotter Into The Woodshop

Hanging plotters, or two steppers controlling a dangling Sharpie marker on an XY plane, are nothing new to our community. But have you ever thought of trading out the Sharpie for a wood router bit and cutting through reasonably thick plywood sheets? That would give you a CNC machine capable of cutting out wood in essentially whatever dimensions you’d like, at reasonably low-cost. And that’s the idea behind [Bar]’s Maslow. It’s going to be a commercial product (we hope!), but it’s also entirely open source and indubitably DIYable.

[Bar] walks us through all of the design decisions in this video, which is a must-watch if you’re planning on building one of these yourself. Basically, [Bar] starts out like any of us would: waaaay over-engineering the thing. He starts out with a counterweight consisting of many bricks, heavy-duty roller chain, and the requisite ultra-beefy motors to haul that all around. At some point, he realized that there was actually very little sideways force placed on a sharp router bit turning very quickly. This freed up a lot of the design.

His current design only uses two bricks for counterweights, uses lighter chains, and seems to get the job done. There’s a bit of wobble in the pendulum, which he admits that he’s adjusted for in software. Motors with built-in encoders and gearing take care of positioning accurately. We haven’t dug deeply enough to see if there’s a mechanism to control the router’s plunge, which would be great to cut non-continuous lines, but first things first.

Taking the wall plotter into the woodshop is a brilliant idea, but we’re sure that there’s 99% perspiration in this design too. Thanks [Bar] for making it open! Best of luck with the Kickstarter. And thanks to [Darren] for the tip.