3D Printed Key-Code Is Plastic Digital Logic

3D printers are great for creating static objects, but if you’re clever, it’s possible to print functional devices. If you’re absolutely brilliant you can go far beyond that, which is the case here. This door handle with a key-code lock does it all with 3D printing using mechanism designs that look like alien technology. This is just one application of a much more interesting mechanical digital logic they’re developing (PDF).

Working from the [Hasso-Plattner-Institut], the research team is focusing on metamaterials as mechanisms in and of themselves. The crux of this lock is a series of bistable springs that — if the correct code is entered — will trigger in series to unlock the door. The project builds on the grid of shearing cells seen in the door handle we featured last year. It happens quickly in the video, but the intricate cascade of the handle unlocking is a treat to witness.

It’s a fascinating show of mechanical design. The common elements of digital electronics are all present: set or unset bits, logic gates, propagation issues, the whole works. But there are added challenges in this system, like the need for special cells that can turn the logic chain by 90 degrees and split the signal into more than one part.

This signal splitting is seen in the upper right (bifurcation) and leads into what is in effect an amplifier. The locking bolt must be moved twice the distance of a normal cell, so a dual-cell input is necessary to offset the loss of force from the incoming smaller cells. Cognitively we understand this, but we’re still trying to gain an intuitive sense of the amplifer mechanism.

One thing’s for sure, the overall concept is far cooler than this admittedly awesome door lock mechanism. The paper is worth your time for a deep dive. It mentions their design editor software. You can play with it online but we don’t think it’s been updated to include the new logic cells yet.

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VCF: 3D Printing In The 80s

The Vintage Computer Festival East is going down right now, and I’m surrounded by the height of technology from the 1970s and 80s. Oddly enough, Hackaday frequently covers another technology from the 80s, although you wouldn’t think of it as such. 3D printing was invented in the late 1980s, and since patents are only around for 20 years, this means 3D printing first became popular back in the 2000’s.

In the 1970s, the first personal computers came out of garages. In the early 2000s, the first 3D printers came out of workshops and hackerspaces. These parallels pose an interesting question – is it possible to build a 1980s-era 3D printer controlled by a contemporary computer? That was the focus of a talk from [Ethan Dicks] of the Columbus Idea Foundry this weekend at the Vintage Computer Festival.

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Endstops That Stay Out Of The Way

In the course of building a new delta printer, [thehans] decided he needed his own endstop design that used minimal hardware. Endstops are just switches that get hit when the printer moves at the extreme of an axis, but [thehans] wanted something with a bit of refinement for his BigDelta 3D Printer build.

The result is a small unit that cradles a microswitch and needs only a single zip tie that mounts flush, resulting in a super tidy looking piece. In addition, it mounts on the delta’s v-slot rails such that the mount does not take up any of the machine’s range of motion, because the carriage can travel past it. It is a parametric design made in OpenSCAD, so feel free to modify it to accommodate other types of switches.

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The Midwest RepRap Festival Spectacular

Every year, nestled between a swine auction and beef auction at the fairgrounds in Goshen, Indiana, the world’s greatest 3D-printing meetup happens. The Midwest RepRap Festival draws the greatest minds in 3D printing from around the world, with teams flying in from Prague, Oxford, and Hong Kong. This year was bigger than any other year. Over 1,000 people ventured forth into the sticks to attend this awesome festival dedicated to DIY printers.

What did we see this year? The PartDaddy, SeeMeCNC’s 18-foot-tall delta printer made an appearance. We saw a new extruder from E3D, and an announcement that Open Source filaments will soon be a reality. True color printing with a five filament CMYKW system is weird and cool. DIY resin printers using laser diodes and galvos are now a thing. An Easy Break Oven isn’t broken. Printers with an infinite build volume now exist, and it skirts around a MakerBot patent, too.

There was more to see at MRRF than a single weekend would allow. [Jason Kridner] from BeagleBone was there talking about the latest in fancy single-chip Linux computers. Hackerspaces were there talking about their coolest builds and doing the calculations necessary to strap model rocket engines to 3D printed rockets. A few local colleges sent teams out to talk about their efforts to bring additive manufacturing to their programs. YouTube personalities were there. Check out the rest of the goodies we saw below.

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MRRF 17: A Working MakerBot Cupcake

The Midwest RepRap Festival is the best place to go if you want to see the latest in desktop 3D printing. This weekend, we saw full-color 3D printers, a printer with an infinite build volume, new extruders, a fantastic development in the pursuit of Open Source filament, and a whole bunch of D-bots. If you want the bleeding edge in 3D printing, you’re going to Goshen, Indiana.

Of course, it wasn’t always like this. In 2009, MakerBot released the Cupcake, a tiny printer that ushered in the era of democratized 3D printing. The Cupcake was a primitive machine, but it existed, it was open source, and it was cheap – under $500 if you bought it at the right time. This was the printer that brought customized plastic parts to the masses, and even today no hackerspace is complete without an unused Cupcake or Thing-O-Matic sitting in the corner.

The MakerBot Cupcake has not aged well. This should be expected for a technology that is advancing as quickly as 3D printing, but today it’s rare to see a working first generation MakerBot. Not only was the Cupcake limited by the technology available to hackers in 2009, there are some pretty poor design choices in these printers. There’s a reason that old plywood MakerBot in your hackerspace isn’t used anymore – it’s probably broken.

This year at MRRF, [Ryan Branch] of River City Labs brought out his space’s MakerBot Cupcake, serial number 1515 of 2,625 total Cupcakes ever made. He got his Cupcake to print a test cube. If you’re at all familiar with the Cupcake, yes, this is a hack. It’s a miracle these things ever worked in the first place.

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MRRF 17: Laser Resin Printers

The Midwest RepRap Festival is the best 3D printer con on the planet. In the middle of Indiana, you’ll find the latest advances for CNC hot glue guns and the processes that make squirting filament machines better, more accurate, and more efficient. There’s more to 3D printing than just filament-based machines, though, and for the last few MRRFs we’ve been taking a look at resin-based machines.

While most of the current crop of resin printers use either DLP projectors or LCDs and a big, bright backlight [Mark Peng]’s Moai printer uses a 150 mW laser diode and galvos. This is somewhat rare in the world of desktop 3D printers, thanks in no small part to the ugliness between Formlabs and 3D Systems. Still, it’s a printer that looks fantastic and produces prints that are far beyond what’s possible with a filament-based machine.

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MRRF 17: True Color 3D Printing

3D printing has evolved to a point where dual extrusion isn’t really that special anymore. A few years ago, a two-color frog print would have been impressive, but this isn’t the case anymore. The Midwest RepRap Festival is all about the bleeding edge of what 3D printers are capable of, and this year is no exception. This year, we were graced with a few true multicolor filament-based 3D printers. The biggest and best comes from [Daren Schwenke] and the rest of the Arcus3D crew. This printer is a full color, CMYKW mixing printer that’s able to print in any color imaginable.

The bizarre mixing hotend, powered by a brushless motor

The electronics for this printer are, to say the least, very weird. The controller board is BeagleBone Black plus a CRAMPS running Machinekit. The hotend is bizarre, feeding six PTFE tubes into a weird water-cooled assembly that mixes and squirts filament out of the nozzle with the help of a small brushless motor. Thanks to a clever design, the end effector of the hotend weighs only about 150 grams – about the same as any other delta printer out there – and this printer is able to move very fast.

Over the last year, we’ve seen a lot of improvements in the state of multi-material and multi-color extrusion for 3D printers. At last year’s Maker Faire NY, Prusa’s i3 quad extruder made an appearance alongside the ORD Solutions RoVa4D printer. These are two completely different approaches to multicolor 3D printing, with the RoVa mixing filament, and the Prusa merely extruding multiple colors. Both approaches have their merits, but mixing extruders are invariably harder to build and the software stack to produce good prints isn’t well-defined.

Even though we’re still in the early years of full-color filament-based printing, this is still an awesome result. In a few years, we’ll be able to look back on [Daren]’s efforts and see where our full-color 3D printers came from – open source efforts to create the best hardware possible.

[Daren] has been working on this printer for a while, and he’s been uploading all his project updates to hackaday.io. You can check out the build log here.