Woodworker Goes From 3D-Printing Skeptic To Believer

December 20, 2018 by Dan Maloney 30 Comments

If there’s one place where the old ways of doing things live a longer life than you’d otherwise expect, it’s the woodshop. Woodworkers have a way of stubbornly sticking to tradition, and that usually works out fine. But what does it take to change a woodworker’s mind about a tool that seems to have little role in the woodshop: the 3D-printer?

That’s the question [Marius Hornberger] asked himself, and at least for him, there are a lot of woodworking gadgets that can be 3D-printed. [Marius] began his journey into additive manufacturing three years ago as a skeptic, not seeing how [Benchy] and friends could be of any value to his endeavors. But as is often the case with a tool that can build almost anything, all it takes is a little ingenuity to get started. His first tool was a pair of soft jaws for his bench vise. This was followed by a flood of useful doodads, including a clever center finder for round and square stock, custom panels for electrical switches, and light-duty pulleys for some of the machines he likes to build. But [Marius] obviously has an issue with dust, because most of his accessories have to do with helping control it in the shop. The real gem of this group is the hose clamp for spiral-reinforced vacuum hose; standard band clamps don’t fit well on those, but his clamps have an offset that straddles the wire for a neat fit. Genius!

[Marius] has kindly made all his models available on Thingiverse, so feel free to dig in and start kitting out your shop. Once you do maybe you can start building cool things like his all-wood scissors lift.

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3D Printed Head Can Unlock Your Phone

December 19, 2018 by Al Williams 23 Comments

[Thomas Brewster] writes for Forbes, but we think he’d be at home with us. He had a 3D printed head made in his own image and then decided to see what phones with facial recognition he could unlock. Turns out the answer is: most of them — at least, those running Android.

The models tested included an iPhone X, an LG, two Samsung phones, and a OnePlus. Ironically, several of the phones warn you when you enroll a face that the method may be less secure than other locking schemes. Conversely, one phone had a faster feature that is known to make the phone less secure.

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Hacker Makes A Flawless Booby Trap, Strikes Back Against Package Thieves

December 17, 2018 by Ben James 158 Comments

[Mark Rober] was fed up with packages going missing. He kept receiving notifications that his shipments had been delivered, but when checking his porch he found nothing there. Reviewing the CCTV footage revealed random passers-by sidling up to his porch and stealing his parcels. It was time to strike back. Over six months, [Mark] and his friends painstakingly designed, prototyped and iterated the perfect trap for package thieves, resulting in a small unit disguised as an Apple HomePod. The whole scheme is wonderfully over-engineered and we love it.

The main feature of the device is a spinning cup on the top which contains a large amount of glitter. When activated, it ejects glitter in every directions. You could say it’s harmless, as it’s just glitter. But then again, glitter has a way of staying with you for the rest of your life — turning up at the least expected times. It certainly leaves an emotional impression.

Activation is quite clever; the fake package sits on the porch until an accelerometer detects movement. At that point, GPS checks to see if the package has traveled outside a geo-fence around [Mark]’s house. A signal is then sent to the four smartphones to start recording — yes, that’s right, there are 4 phones inside, one on each side to capture the reaction of the thief.

How can [Mark] be so confident that he’ll be able to recover the four phones and their footage? That’s answered by GPS tracking and a can of fart spray actuated by a 3D printed cam and DC motor, ensuring the thief won’t want this package around for long. This actuator and the glitter motor are controlled by a custom PCB, which also triggers the phones to start recording through their headphone jacks and detects the opening of the package with some microswitches. This is truly a masterpiece that outsmarts the package thieves in a way that leaves an impression while still being playful.

(Editor’s Note 2: On 12/20/18 it was announced that two of the five thieves shown in the originally video were staged, apparently without [Mark Rober’s] knowledge. Here is his statement on the matter.)

(Editor’s Note 1: [Sean Hodgins] wrote in with bonus video on how the Glitter Bomb works and how it was made.)

If booby traps are your thing, we’ve got you covered. Check out this ticking bomb style puzzle, or this crate challenge which is rigged to blow.

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How Not To Design A 3D Printed Belt Clamp

December 16, 2018 by Donald Papp 17 Comments

[Mark Rehorst] has been busy with his Ultra MegaMax Dominator (UMMD) design for a 3D printer, and one of the many things he learned in the process was how not to design a 3D printed belt clamp. In the past, we saw how the UMMD ditched the idea of a lead screw in favor of a belt-driven Z axis, but [Mark] discovered something was amiss when the belts were flopping around a little, as though they had lost tension. Re-tensioning them worked, but only for a few days. It turned out that the belt clamp design he had chosen led to an interesting failure.

The belts used were common steel-core polyurethane GT2 belts, and the clamp design uses a short segment of the same belt to lock together both ends, as shown above. It’s a simple and effective design, but one that isn’t sustainable in the longer term.

The problem was that this design led to the plastic portion of the belt stretching out and sliding over the internal steel wires. The stretching of the polyurethane is clear in the image shown here, but any belt would have had the same problem in the clamp as it was designed. [Mark] realized it was a much better idea to use a design in which the belts fold over themselves, so the strain is more evenly distributed.

[Mark] has been sharing his experiences and design process when it comes to building 3D printers, so if you’re interested be sure to check out the UMMD and its monstrous 695 mm of Z travel.

OpenLH: Automating Biology For Everyone

December 16, 2018 by Al Williams 9 Comments

When we took a biology lab, you had to use a mouth pipette to transfer liquids around. That always seemed odd to use your mouth to pick up something that could be dangerous. It’s also not very efficient. A modern lab will use a liquid handling robot, but these aren’t exactly cheap. Sometimes these are called pipettors and even a used one on eBay will set you back an average of $1,000 — and many of them much more than that. Now there’s an open source alternative, OpenLH, that can be built for under $1,000 that leverages an open source robot arm. You can find a video about the system below.

The robot arm, a uArm Swift Pro, is the bulk of the cost. The Pro can also operate as a 3D printer or a laser engraver with a little work. In fact, we wondered if you could use the arm to make a 3D printer and then print the parts you need to convert it to a liquid handler. Seems like it should work.

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Shape Shifting Structures Work With Magnets

December 15, 2018 by Brian McEvoy 12 Comments

In The Dark Knight, Lucius Fox shows Bruce Wayne a neat bit of memory weave fabric. In its resting state, it is a light, flexible material, but when an electrical current is applied, it pops into a pre-programmed shape. That shape could be a tent or a bat-themed paraglider. Science has not caught up to Hollywood in this regard, but the concept has been demonstrated in a material which increases its rigidity up to 318% within one second when placed in a magnetic field. Those numbers do not mean a lot by themselves, but increasing rigidity in a reversible, non-chemical way is noteworthy.

The high-level explanation is that hollow tubes are 3D printed and filled with magnetorheological fluid which becomes more viscous in the presence of a magnet because the ferrous suspended particles bunch up to form chains instead of sliding over one another. Imagine a bike tire filled with gel, and when you need a little extra traction the tire becomes softer, but when you are cruising on a paved trail, the tire becomes as hard as a train wheel to reduce friction. That could be darn handy in more places than building a fast bike.

Imploding Tiny 3D Prints

December 15, 2018 by Al Williams 10 Comments

If you think about 3D printing, the ultimate goal would be to lay down specific atoms or molecule and build anything. Despite a few lab demonstrations at that scale, generally, it is easier to print in the macro scale than the micro. While it won’t get down to the molecule level, implosion fabrication is a new technique researchers hope will allow you to print large things and then shrink them. The paper describing the process appeared in Science. If you don’t want to pay your way through the paywall, you can read a summary on NewScientist or C&EN. Or you can scour the usual sources.

The team at MIT uses the same material that is found in disposable diapers. A laser traces patterns and the light reacts to a chemical implanted in the diaper material (sodium polyacrylate). That material can swell to many times its normal size which is why it is used in diapers. In this case, though, the material is swollen first and then reduced back to normal size.

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