Stripping 3D Printed Gears For Science

October 17, 2017 by Tom Nardi 33 Comments

While 3D printing is now well on its way to becoming “boring” in the same way that a table saw or lathe is, there was a time when the media and even some early adopters would have told you that the average desktop 3D printer was perhaps only a few decades behind the kind of replicator technology we saw on the Enterprise. But as the availability of these machines increased and more people got to see one up close, reality sunk in pretty quickly.

Many have dismissed the technology as little more than a novelty, and even within the 3D printing community itself there’s a feeling that most printers are used for little more than producing “dust collectors”. Some would see this attitude as disheartening, but the hackers over at [Gear Down For What?] see it as a challenge. They’ve made it their mission to push printed parts to increasingly ridiculous heights to show just what the technology is capable of, and in their latest entry, set out to push a pair of 3D printed gearboxes to failure.

The video starts out with a head to head challenge between two of their self-designed gearboxes. As they were spun up with battery powered drills, the smaller of the two quickly gave up the ghost, stripping out at 228 lbs. The victor of the first round then went on to pull a static load, only to eventually max out the scale at an impressive 680 lbs.

The gearbox may have defeated the scale, but the goal of the experiment was to run it to failure. By rigging up a compound pulley arrangement, they were able to double the amount of force their scale could detect. With this increased capacity the gearbox was then run up to an astonishing 1,000 lbs before it started to slip.

But perhaps the most impressive: after they got the gearbox disassembled, it was discovered that only a single planet gear out of the ten had broken. Even then, judging by how the gear sheared, the issue was more likely due to poor layer adhesion during printing than from stress alone. No gears were stripped, and in fact no visible damage was seen anywhere in the mechanism. The team is currently unable to explain the failure, other than to say that the stresses may have been so great that the plastic deformed enough that the gears were no longer meshed tightly.

This isn’t the first time we’ve checked in with the team at [Gear Down For What?], just a few months ago they impressed us by lifting an anvil with one of their printed mechanisms. They’re also not the only ones curious to find out just how far 3D printed plastic can go.

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Echo Dot Finds Swanky New Home In Art Deco Speaker

October 16, 2017 by Tom Nardi 15 Comments

The phrase “They don’t make them like they used to” is perhaps best exemplified by two types of products: cars and consumer electronics. Sure, the vehicles and gadgets we have now are so advanced that they may as well be classified as science-fiction when compared to their predecessors, but what about that style. Our modern hardware can rarely hold a candle to the kind of gear you used to be able to buy out of the “Sears, Roebuck and Company” catalog.

So when [Democracity] came into possession of a wickedly retro art deco speaker, it’s no surprise he saw it as a perfect opportunity to bring some of that old school style into the 21st century by rebuilding it with an Amazon Echo Dot at its core. The fact that the original device was a speaker and not a full radio made the conversion much easier, and will have everyone trolling yard sales for months trying to find a donor speaker to build their own.

To start the process, [Democracity] popped the panels off and ripped out what was left of the speaker’s paper cone and coil. In a stroke of luck, the opening where the driver used to go was nearly the perfect size to nestle in the Echo Dot. With a 3D printed cradle he found on Thingiverse and a liberal application of epoxy, the Dot could get snapped into the speaker like it was always meant to be there.

[Democracity] then picked up some absolutely gorgeous speaker cloth on eBay and hot glued it to the inside of the panels. What was presumably the volume knob was pulled out of the bottom and turned out to be a perfect place to run the Dot’s USB cable out of.

A lesser man would have called this project completed, but [Democracity] knows that no hack is truly complete without the addition of multicolored blinking LEDs. With the RGB LED strips installed inside, the light is diffused through the cloth panels and creates a pleasing subtle effect. You can almost imagine a couple of vacuum tubes glowing away inside there. Judging by the final product, it’s no surprise [Democracity] has a fair bit of experience dragging audio equipment kicking and screaming into the modern era.

This isn’t the first time we’ve seen an old piece of audio equipment get a high-tech transfusion, and isn’t even the first time we’ve seen the Dot used to do it. But it’s certainly the one we’d most like to see sitting on our shelf.

The Fine Art Of Heating And Cooling Your Beans

October 16, 2017 by Tom Nardi 27 Comments

They say that if something is worth doing, it’s worth doing right. Those are good words to live by, but here at Hackaday we occasionally like to adhere to a slight variation of that saying: “If it’s worth doing, it’s worth overdoing”. So when we saw the incredible amount of work and careful research [Rob Linnaeus] was doing just to roast coffee beans, we knew he was onto something.

The heart of his coffee roaster is a vortex chamber with an opening on the side for a standard heat gun, and an aperture in the top where an eight cup flour sifter is to be placed. [Rob] modeled the chamber in Fusion 360 and verified its characteristics using RealFlow’s fluid simulation. He then created a negative of the chamber and printed it out on his Monoprice Maker Select 3D printer.

He filled the mold with a 1:1 mix of refractory cement and perlite, and used the back of a reciprocating saw to vibrate the mold as it set so any air bubbles would rise up to the surface. After curing for a day, [Rob] then removed the mold by heating it and peeling it away. Over the next several hours, the cast piece was fired in the oven at increasingly higher temperatures, from 200 °F all the way up to 500 °F. This part is critical, as trapped water could otherwise turn to steam and cause an explosion if the part was immediately subjected to high temperatures. If this sounds a lot like the process for making a small forge, that’s because it basically is. Continue reading “The Fine Art Of Heating And Cooling Your Beans” →

LEGO Row Boat Is The Poolside Companion You Didn’t Know You Needed

October 15, 2017 by Tom Nardi 9 Comments

Maybe it’s the upbeat music, or the views of a placid lake at sunset, or perhaps it’s just seeing those little plastic rods pumping away with all their might. Whatever the reason may be, the video [Vimal Patel] posted of his little remote controlled LEGO row boat cruising around on the open water is sure to put a smile on the face of even the most jaded hacker.

[Vimal] tells us that his creation is made up of over 140 unmodified LEGO parts, and is controlled over Bluetooth which connects to an app on his phone. While we would like to see some more detail on the reciprocating module he came up with to drive the boat’s paddles, we have to admit that the images he provided in his flickr album for the project are impeccable overall. If the toy boat game doesn’t work out for [Vimal], we think he definitely has what it takes to get into the advertising department for a car manufacturer.

[Vimal] was even kind enough to provide a LEGO Digital Designer file for the project, which in the world of little rainbow colored blocks is akin to releasing the source code, so you can build up your own fleet before next summer.

It’s worth noting that [Vimal] is something of a virtuoso in the world of modular building blocks, and no stranger here at Hackaday. His self lacing shoe impressed earlier this year, and this isn’t even his first LEGO watercraft.

All he has to do now to reach the true pinnacle of LEGO construction is to start building with giant versions of everyone’s favorite block.

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Cheap 3D Printers Make Cheaper(er) Bioprinters

October 15, 2017 by Tom Nardi 27 Comments

In case you missed it, prices on 3D printers have hit an all time low. The hardware is largely standardized and the software is almost exclusively open source, so it makes sense that eventually somebody was going to start knocking these things out cheap. There are now many 3D printers available for less than $300 USD, and a few are even dipping under the $200 mark. Realistically, this is about as cheap as these machines are ever going to get.

A startup by the name of 3D Cultures has recently started capitalizing on the availability of these inexpensive high-precision three dimensional motion platforms by co-opting an existing consumer 3D printer to deliver their Tissue Scribe bioprinter. Some may call this cheating, but we see it for what it really is: a huge savings in cost and R&D time. Why design your own kinematics when somebody else has already done it for you?

Despite the C-3PO level of disguise that 3D Cultures attempted by putting stickers over the original logo, the donor machine for the Tissue Scribe is very obviously a Monoprice Select Mini, the undisputed king of beginner printers. The big change of course comes from the removal of the extruder and hotend, which has been replaced with an apparatus that can heat and depress a standard syringe.

At the very basic level, bioprinting is performed in the exact same way as normal 3D printing; it’s merely a difference in materials. While 3D printing uses molten plastic, bioprinting is done with organic materials like algae or collagen. In the Tissue Scribe, the traditional 3D printer hotend has been replaced with a syringe full of the organic material to be printed which is slowly pushed down by a NEMA 17 stepper motor and 8mm leadscrew.

The hotend heating element and thermistor that once were used to melt plastic are still here, but now handle warming the metal frame used to hold the syringe. In theory these changes would have only required some tweaks to the firmware calibration to get working. Frankly, it makes perfect sense, and is certainly a much easier to pull off than some of the earlier attempts at homebrew biological printers we’ve seen.

We won’t comment on the Tissue Scribe’s price point of $999 USD except to say that in the field of bioprinters, that’s pocket change. Still, it seems inevitable that somebody will build and document their own bolt-on biological extruder now that 3D Cultures has shown how simple it really is, so they may find themselves undercut in the near future.

If all this talk of hot extruded collagen has got you interested, we’ve seen some excellent resources on the emerging field of bioprinting that will probably be right up your alley.

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Encrypt Data On The Fly On A Pi With Cryptopuck

October 13, 2017 by Tom Nardi 22 Comments

There was a time that encryption was almost a dirty word; a concept that really only applied to people with something to hide. If you said you wanted to encrypt your hard drive, it may as well have been an admission to a crime. But now more than ever it’s clear that encryption, whether it’s on our personal devices or on the web, is a basic necessity in a digital society. The age of Big Data is upon us, and unless you’re particularly fond of being a row in a database, you need to do everything you can to limit the amount of plaintext data you have.

Of course, it’s sometimes easier said than done. Not everyone has the time or desire to learn how the different cryptographic packages work, others may be working on systems that simply don’t have the capability. What do you do when you want to encrypt some files, but the traditional methods are out of reach?

Enter the latest project from [Dimitris Platis]: Cryptopuck. By combining the ever-versatile Raspberry Pi Zero, some clever Python programs, and a few odds and ends in a 3D printed case, he has created a completely self-contained encryption device that anyone can use. Stick a USB flash drive in, wait for the LED to stop blinking, and all your files are now securely encrypted and only accessible by those who have the private key. [Dimitris] envisions a device like this could be invaluable for reporters and photographers on the front lines, protesters, or really anyone who needs a discreet way of quickly securing data but may not have access to a computer.

The hardware side is really just the Pi, a switch, a single LED for notifications, and a battery. The real magic comes from the software, where [Dimitris] has leveraged PyCrypto to perform the AES-256 encryption, and a combination of pyinotify and udiskie to detect new mounted volumes and act on them. The various Python scripts that make up the Cryptopuck suite are all available on the project’s GitHub page, but [Dimitris] makes it very clear the software is to be considered a proof of concept, and has not undergone any sort of security audit.

For some background information on how the software used by the Cryptopuck works you may want to check out this excellent primer from a few years back; though if you’d like to read up on why encryption is so important, you don’t need to go nearly as far back in time.

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Making Ice Cream With Heavy Metal

October 11, 2017 by Tom Nardi 25 Comments

After his last project left him with an eleven-pound block of aluminum, [Jason] got to thinking of what most of us would in that situation: fresh made ice cream. His mind was on the frozen concoctions of the aptly named Cold Stone Creamery, a mall food court staple where a chilled stone is used to turn fresh ingredients into made to order sundaes.

[Jason] did the math and found that an eleven-pound chunk of aluminum can absorb a little over 67,000 joules, which is over twice the energy required to freeze 100 g of water. In place of water he would be using cream, condensed milk, and strawberries, but believed there was a large enough safety factor to account for the differences between his ingredients and pure water.

His first attempt didn’t go exactly as planned, but with his Flir One he was able to back up his theoretical numbers with some real-world data. He found that he needed to start the aluminum block at a lower temperature before adding his ingredients, and through experimentation determined the block only had enough energy to freeze 30 g of liquid.

In the end [Jason] was satisfied with the frozen treat he managed to make from the leftovers of his radial mill project, but theorizes that an ever better solution would be to use a brine solution and drop the aluminum block all together.

Of course, if putting food on a slab of metal from your workshop doesn’t sound too appealing, you could always go the NASA route and freeze dry it. Either method will probably make less of a mess than trying to print objects with it.