3D Printed Tourniquets Are Not A Cinch

June 28, 2018 by Brian McEvoy 32 Comments

Saying that something is a cinch is a way of saying that it is easy. Modeling a thin handle with a hole through the middle seems like it would be a simple task accomplishable in a single afternoon and that includes the time to print a copy or two. We are here to tell you that is only the first task when making tourniquets for gunshot victims. Content warning: there are real pictures of severe trauma. Below, is a video of a training session with the tourniquets in Hayat Center in Gaza and has a simulated wound on a mannequin.

On the first pass, many things are done correctly: the handle is the correct length and diameter, the strap hole fit the strap, and the part is well oriented on the platen. As with many first iterations, it looks good on a screen, but in the real world, we all live under Murphy’s law. In practice, some of the strap holes had sharp edges that cut into the strap, and one of the printed buckles broke unexpectedly.

On the whole, the low cost and availability of the open-source tourniquets outweigh the danger of operating without them. Open-source medical devices are not just for use in the field, they can help with training too. This tourniquet is saving people and proving that modeling skills can be a big help in the real world.
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Tiny Printers Get Color Mixing

June 28, 2018 by Brian Benchoff 8 Comments

Last weekend was the inaugural East Coast RepRap Festival in beautiful Bel Air, Maryland. Like it’s related con, the Midwest RepRap Festival, ERRF is held in the middle of nowhere, surrounded by farms, and is filled with only people who want to be there. It is the anti-Maker Faire; only the people who have cool stuff to show off, awesome prints, and the latest technology come to these RepRap Fests. This was the first ERRF, and we’re looking forward to next year, where it will surely be bigger and better.

One of the stand-out presenters at ERRF didn’t have a big printer. It didn’t have normal stepper motors. There weren’t Benchies or Marvins or whatever the standard test print is these days. [James] is showing off tiny printers. Half-scale printers. What’s half the size of a NEMA 17 stepper motor? A NEMA 8, apparently, something that isn’t actually a NEMA spec, and the two companies that make NEMA 8s have different bolt hole patterns. This is fun.

If these printers look familiar, you’re right. A few years ago at the New York Maker Faire, we checked out these tiny little printers, and they do, surprisingly, print. There are a lot of tricks to make a half-size printer, but the most impressive by far is the tiny control board. This tiny little board is just 2.5 by 1.5 inches — much smaller than the standard RAMPS or RAMBO you’d expect on a DIY printer. On the board are five stepper drivers, support for two heaters, headers for OLEDs and Graphic LCDs, and a switching regulator. It’s a feat of microelectronics that’s impressive and necessary for a half-size printer.

Since we last saw these tiny printers, [James] has been hard at work expanding what is possible with tiny printers. The most impressive feat from this year’s ERRF was a color-mixing printer built around the same electronics as the tiny printers. The setup uses normal-size stepper motors (can’t blame him) and a diamond-style hotend to theoretically print in three colors. If you’ve ever wanted a tiny printer, this is how you do it, and I assure you, they’re very, very cute.

Pool Ball Return System Chalked Up To Ingenuity

June 27, 2018 by Kristina Panos 12 Comments

Do you play pool? If so, you probably take the automatic ball return systems in bar and billiard hall tables for granted. [Roger Makes] was tired of walking around his home table to collect the balls every time he wanted to play, so he designed a time-saving ball return system.

Instead of falling into the little netted baskets that came with the table, the balls now drop into 3D-printed pockets and ride along dowel rod rails into a central collection box, which is suspended by straps beneath the rack-em-up end of the table. The rails themselves are fortified with ABS ribs that keep the balls from falling through.

Pool is all about geometry, and this really hit home when [Roger] was trying to merge the funnel part of the pocket with the exit chute in the design phase. He covered all the angles with a modular design that lets the chute rotate freely, which takes a lot of stress away from the dowel rods. We’ve got the video cued up after the break, so don’t bother with getting out your film canister full of quarters.

We can’t wait to see what [Roger Makes] next. Maybe it’ll be something like this OpenCV score-keeping system.

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Apple Coin Bank Plants The Seed Of Saving

June 25, 2018 by Kristina Panos 14 Comments

Consider the piggy bank. Behind that innocent, docile expression is a capitalistic metaphor waiting to ruin your fond memories of saving for that BMX bike or whatever else it was that drove home the value of a dollar. As fun as it is to drop a coin in a slot, the act of saving your pennies and learning financial responsibility could be a bit more engaging.

It seems like [gzumwalt] feels the same way. He’s designed a coin bank for his grand-kids that takes a more active role in the deposit process—it straight up eats the things. Put a coin on the platform and the upper half of the apple’s face is pushed open by an arm that pulls the coin inside on its return path.

Continuing with the money-saving theme, [gzumwalt] didn’t use a micro or even a 555. No, the core of this project is a pair of micro lever switches, a small gear motor, and 4.5V DC. When a coin hits the platform, the first switch engages the motor. The motor drives a 3-D printed mechanism modeled after Hoeckens’ linkage, which converts rotational motion to (nearly) straight-line motion. The second switch stops the cycle. Confused? You can sink your teeth into it after the break.

Don’t worry, the kids don’t have to slice up the apple when it’s time to go to the candy store, ’cause there’s a screw-in hatch on the bottom. This is because [gzumwalt] is a wizard of 3-D printing and design. Not convinced? Check out his balloon-powered engine or his runs-on-air plane.

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Lost In Space Gets 3D Printing Right

June 25, 2018 by Tom Nardi 100 Comments

When it has become so common for movies and television to hyper-sensationalize engineering, and to just plain get things wrong, here’s a breath of fresh air. There’s a Sci-Fi show out right now that wove 3D printing into the story line in a way that is correct, unforced, and a fitting complement to that fictional world.

With the amount of original content Netflix is pumping out anymore, you may have missed the fact that they’ve recently released a reboot of the classic Lost in Space series from the 1960’s. Sorry LeBlanc fans, this new take on the space traveling Robinson family pretends the 1998 movie never happened, as have most people. It follows the family from their days on Earth until they get properly lost in space as the title would indicate, and is probably most notable for the exceptional art direction and special effects work that’s closer to Interstellar than the campy effects of yesteryear.

But fear not, Dear Reader. This is not a review of the show. To that end, I’ll come right out and say that Lost in Space is overall a rather mediocre show. It’s certainly gorgeous, but the story lines and dialog are like something out of a fan film. It’s overly drawn out, and in the end doesn’t progress the overarching story nearly as much as you’d expect. The robot is pretty sick, though.

No, this article is not about the show as a whole. It’s about one very specific element of the show that was so well done I’m still thinking about it a month later: its use of 3D printing. In Lost in Space, the 3D printer aboard the Jupiter 2 is almost a character itself. Nearly every member of the main cast has some kind of interaction with it, and it’s directly involved in several major plot developments during the season’s rather brisk ten episode run.

I’ve never seen a show or movie that not only featured 3D printing as such a major theme, but that also did it so well. It’s perhaps the most realistic portrayal of 3D printing to date, but it’s also a plausible depiction of what 3D printing could look like in the relatively near future. It’s not perfect by any means, but I’d be exceptionally interested to hear if anyone can point out anything better.

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Clock This! A 3D-Printed Escapement Mechanism

June 21, 2018 by Jenny List 13 Comments

Traditional mechanical clockmaking is an art that despite being almost the archetype of precision engineering skill, appears rarely in our world of hardware hackers. That’s because making a clock mechanism is hard, and it is for good reason that professional clockmakers serve a long apprenticeship to learn their craft.

Though crafting one by hand is no easy task, a clock escapement is a surprisingly simple mechanism. Simple enough in fact that one can be 3D-printed, and that is just what [Josh Zhou] has done with a model posted on Thingiverse.

The model is simply the escapement mechanism, so to make a full clock there would have to be added a geartrain and clock face drive mechanism. But given a pair of 608 skateboard wheel bearings and a suitable weight and string to provide a power source, its pendulum will happily swing and provide that all-important tick. We’ve posted his short video below the break, so if Nixie clocks aren’t enough for you then perhaps you’d like to take it as inspiration to go mechanical.

A pendulum escapement of this type is only one of many varieties that have been produced over the long history of clockmaking. Our colleague [Manuel Rodriguez-Achach] took a look at some of them back in 2016.

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Print Physical Buttons For Your Touch Screen

June 20, 2018 by Brian McEvoy 5 Comments

Modern handheld gaming hardware is great. The units are ergonomic powerhouses, yet many of us do all our portable gaming on a painfully rectangular smartphone. Their primary method of interaction is the index finger or thumbs, not a D-pad and buttons. Shoulder triggers have only existed on a few phones. Bluetooth gaming pads are affordable but they are either bulky or you have to find another way to hold your phone. Detachable shoulder buttons are a perfect compromise since they can fit in a coin purse and they’re cheap because you can make your own.

[ASCAS] explains how his levers work to translate a physical lever press into a capacitive touch response. The basic premise is that the contact point is always touching the screen, but until you pull the lever, which is covered in aluminum tape, the screen won’t sense anything there. It’s pretty clever, and the whole kit can be built with consumables usually stocked in hardware stores and hacker basements and it should work on any capacitive touch screen.

Physical buttons and phones don’t have to be estranged and full-fledged keyswitches aren’t exempt. Or maybe many capacitive touch switches are your forte.

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