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February 08 2018

Not Your Typical POV Clock

Persistence of vision displays are fun, and a natural for clocks, but they’re getting a little Nixie-ish, aren’t they? There are only so many ways to rotate LEDs and light them up, after all. But here’s something a little different: a POP, or “persistence of phosphorescence” clock.

[Chris Mitchell] turned the POV model around for this clock and made the LEDs stationary, built into the tower that holds the slowly rotated display disk. Printed from glow-in-the-dark PLA, the disk gets charged by the strip of UV LEDs as it spins, leaving behind a ghostly dot matrix impression of the time. The disk rotates on a stepper, and the clock runs on a Nano with an RTC. The characters almost completely fade out by the time they get back to the “write head” again, making an interesting visual effect. Check it out in the video after the break.

Our only quibble is the choice to print the disk rather than cut it from sheet stock. Seems like there has to be commercially available phosphorescent plastic, or even the glow-in-the-dark paper used for this faux LED scrolling sign. But if you’ve got glowy PLA, why not use it?

S.T.E.A.M. Fabrikarium Builds Assistive Tech in Mumbai

Starting this weekend, a group of 65 invited Maker’s from various disciplines, along with 20 awesome Mentors, will gather at the Maker’s Asylum in Mumbai for the five day S.T.E.A.M. Fabrikarium program. The aim is to improve the capabilities of the differently-abled by building and expanding upon existing open source projects. At the same time, the teams will learn more about rapid prototyping techniques.

Among the participants will be at least 15 differently-abled people who will be a part of the whole process of learning as well as providing their inputs on the problems being tackled.  Participants have an opportunity to understand how design thinking works and work on improving the existing designs.

Participants will team up and choose from five existing open source projects:

  • Bionico – a myoelectric prosthesis
  • Braille rap – using a 3D printer as a braille embosser.
  • e-Trotti – a low-cost, removable electrical assistance for wheelchair use, made from electric scooter parts.
  • Project Shiva – customized and beautiful upper limb prosthetics.
  • Flying Wheelchair – a wheelchair specially adapted for use while paragliding.

The Asylum’s fully-fledged workshop facilities offer a wood shop, a laser cutter, a CNC, several 3D printers, electronics tools and instruments and an infectious environment that will allow the participants to learn a lot during the five short days. While working on prototyping their projects, all teams will have constant access to a team of mentors and industry experts who will help solve their problems and give guidance when necessary.

The Maker’s Asylum includes fully-fledged workshop facilities for the build process, and the team succeeded in bringing onboard a slew of industrial partners and supporters to ensure that the program can be offered to the participants for free. That is a great way to bring makerspaces, makers, and the industry together in a symbiotic program that benefits society.  The program was developed in collaboration with My Human Kit , a company from France who selected the five open-source projects mentioned above. The Fabrikarium is made possible via Bonjour-India , which fosters Indo-French partnerships and exchanges.

Hackaday is proud to be a part of this program and will be present to help document all of the awesome projects. Participants will share their progress on Hackaday.io, so watch for updates over the coming week.  To get an idea of what to expect at the S.T.E.A.M. Fabrikarium 2018, check out the video from an earlier version embedded below.

A Freeze Dryer You Can Build in Your Garage

What do trail mix, astronaut ice-cream, and cryogel have in common? This may sound like the introduction to a corny riddle, but they are all things you can make in your garage with a homemade freeze dryer. [The Thought Emporium] built his own freeze dryer with minimum fuss and only a few exotic components like a vacuum pump and a high-quality pressure gauge. The video is also posted after the break which contains a list for the parts and where they can be purchased.

Freeze drying uses a process called cryodesiccation or lyophilization. Below a certain pressure, water skips the liquid phase and goes directly to a gas, so frozen items can transition from ice to dry without a soggy step. When you jump the liquid phase, objects hold their shape when they were frozen, and since no heat is used, you don’t carmelize your sugars.

A freeze-dryer like this has three parts. The first is the pump which doesn’t need any explanation. Next to the pump there must be a water trap. This chilly compartment recondenses the water vapor, so it doesn’t get inside the pump or saturate the things you’re trying to dry. Lastly, there is the drying chamber where your items are placed to have their moisture taken out.

Astronaut ice cream has been made on Hackaday before. [The Thought Emporium] has also been seen including a piece on making your own graphene.

Home Made 8-Bit CPU Is A Wiry Blinky Build

It might look like a random pile of wires to some, but it is far from random: [Paulo Constantino] built this 8-bit CPU himself from scratch. He built his remarkable creation using wires and 74HC shift register chips, plus a selection of LEDs to show the various registers.

Running at a maximum of 5MHz, it has an 8-bit data and address bus, although the latter can be expanded to 16 bits. It’s not mining Bitcoin (yet), but it can do things like play the Mario theme. His latest addition is the addition of the ability to write data out to flash memory, and he is looking to add a keyboard to make programming easier.

At the moment, he has to program the CPU by setting DIP jumpers. It’s an impressive, if somewhat frightening build that [Paulo] says took him a couple of days to design and a week or so to build. We’ve seen a few breadboard CPU builds, (some of which were tidier) and builds with similar shift register chips, but this one scores big in the blinky light and mad genius stakes.

Thanks to [AnalogMind] for the tip!


February 07 2018

Motorized Mini Excavator Rises From Sheets of Plywood

Fathers of Hackaday, we’ve got bad news — you’ve been out-fathered. Behold the mechanism of your undoing: a working miniature excavator, executed in plywood.

To be fair, the rules of the game have changed lately. Time was when a nipper would ask for the impossible, and we dads would never have to deliver. But with CNC routers, 3D-printing, and industrial-grade CAD software you can use for free, the possibility hurdle is getting ever shorter. Still, when his son put in this request, [Alex Lovegrove] really delivered. Everything on this excavator works, from tracks to boom to bucket. There are hundreds of parts, mostly machined from plywood but with a smattering of 3D-printed gears and brackets. The tracks and slew gear are powered by gear motors, while linear actuators stand in for hydraulic rams on the boom. The videos below show the machine under test and the unbearable cuteness of it being loved.

Hacker dads and grandfathers need not despair, of course. There’s plenty of room left for your imagination to run amok. For inspiration, check out this working railway system, or any of the several backyard roller coasters we’ve featured.

Injection Molding iPhone Cases from Trash

We imagine you’ve heard this already, but waste plastic is a problem for the environment. We wrap nearly everything we buy, eat, or drink in plastic packaging, and yet very little of it ends up getting recycled. Worse, it doesn’t take a huge industrial process to melt down a lot of this plastic and reuse it, you can do it at home if you were so inclined. So why aren’t there more localized projects to turn all this plastic trash into usable items?

That the question that [Precious Plastic] asks, and by providing a centralized resource for individuals and communities looking to get into the plastic recycling game, they hope to put a dent in the worldwide plastic crisis. One of their latest projects is showing how plastic trash can be turned into functional iPhone cases with small-scale injection molding.

Pushing plastic into the mold

The video after the break goes into intricate detail about the process involved in creating the 3D CAD files necessary to make the injection molds. Even if you don’t plan on recycling milk jugs at home, the information and tips covered in the video are extremely helpful if you’ve ever contemplated having something injection molded. The video even demonstrates a neat feature in SolidWorks that lets you simulate how molten plastic will move through your mold to help check for problem areas.

Once you’ve designed your mold on the computer, you need to turn it into a physical object. If you’ve got a CNC capable of milling aluminum then you’re all set, but if not, you’ll need to outsource it. [Precious Plastic] found somebody to mill the molds through 3DHubs, though they mention in the video that asking around at local machine shops isn’t a bad idea either.

With the mold completed, all that’s left is to bolt the two sides together and inject the liquid plastic. Here [Precious Plastic] shows off a rather interesting approach where they attach the mold to a contraption that allows them to inject plastic with human power. Probably not something you’d want to do if you’re trying to make thousands of these cases, but it does show that you don’t necessarily need a high tech production facility to make good-looking injection molded parts.

This project reminds us of the tiles made of HDPE plastic with nothing more exotic than what you’d find in the average kitchen. Projects like these really drive home the idea that with the right hardware individuals can turn trash into usable products.

[via 3DHubs]

Quantum Searching in Your Browser

If you’ve made it through the last two posts on quantum computing (QC), then you’ve seen the Quirk simulator, a little of IBM’s web-based offering, and how entanglement and superposition can do strange and possibly wonderful things. However, the superdense encoding I showed you didn’t really feel like a real computer algorithm. This time we will look at Grover’s algorithm which is often incorrectly billed as an “unstructured database search.” In reality, it is an algorithm for making a state — that is a set of qubits — match some desired state without simply setting the state.

By analogy, consider a web service where you guess a number. Most discussions of Grover’s algorithm will tell you that the service will only tell you if the number is correct or not. If the number was from 1 to 16, using traditional computing, you’d have to query the values one at a time to see which is correct. You might get lucky and hit the first time. Or it might take 16 times. With qubits you can get the same result in only four attempts. In fact, if you try more times, you might get the wrong answer. Of course, what you really get is an answer that is probably correct, because that how QC works.

Going Through a Phase

The secret to Grover’s algorithm is there has to exist an oracle function. This function will reverse the phase of the qubits when they have the correct answer. Because of superposition, the values are all at least somewhat likely, but only one gets its phase reversed.

This is why I dislike the database search analogy. Because the oracle function has to know what the answer is ahead of time. I think that a better analogy is a web service, because the rest of the code doesn’t get to know what is happening in the oracle function. With QC, the web service takes all the possible numbers and marks the one that is correct.

Just having the phase reversed isn’t enough, though. We need an operation to effectively subtract the phases from each other. The phases that we didn’t change will cancel out, and the phase that we flipped will become larger. This is known as amplitude amplification. Depending on the total number of qubits, you may have to repeat the entire process, but for now, let’s consider two qubits which can have state |00>, |01>, |10>, and |11>.

The first part of the circuit will create the superimposed states. The inverters set up the original bits in the |1> state and then the H gates create the superposition. I added a chance probe so you can see that now there is exactly a 1 in 4 chance of any single state being the one we’d get if we observed it now.


Match Game

The next step inverts the phase of the item you want to match. Exactly how you’d do that depends on what you want to find, but in our case, we are just going to plug in a constant. That’s easy. The Z gate flips phase and we can control it. By using solid dots and hollow dots on the Probes toolbox, you can ask for any arrangement of 1s (solid) and 0s (hollow) you like. Just put the Z block on a qubit you want to be 1 and then use the dots for the rest. Oddly, it doesn’t matter which qubit the Z box is on (as you will see later) as long as it is a 1 in the resulting pattern. Here’s a search for 10 which is, in this case, our oracle.

Now we get to the Grover diffusion operation which is the heart of the algorithm. What we really want now is to invert the state’s X axis. In Quirk, you can do that by using an X control and then using the small circle with the cross in it under X/Y probes called X-Axis control. Like this:

However, that hides a lot of what is going on. It is really just shorthand for this:

This rotates the qubit around so that X now points to Z , inverts Z (which is now X), and rotates it back. In other words, it inverts around X axis instead of the Z. In practice, I’d use the Quirk shorthand, but for learning purposes, it is nicer to see what’s really happening. Since we only need one pass of the algorithm for two bits, we are done. If you had more, you’d repeat the oracle function and do another diffusion, repeating both until you had enough passes.

You can look at the entire setup with a lot of extra instrumentation in the simulator. Note the phase angle after the Z gate. Only the state of interest flipped. Then notice the probabilities as the qubits flow past the diffusion. You’ll notice that going into the final H gate, the phase angle for the top qubit is 90 degrees instead of 180. That’s because it is only going to be on in one state and not the other.

Try replacing the hollow dot with a solid one, and you’ll “find” |11>. You can also reverse the position of the Z gate and the hollow dot and things will still work.

Bigger, My My

Scaling this up to five qubits is pretty trivial. Here I used the controlled Z gate instead of breaking it out and I put in a lot less instrumentation. You can change the solid dots and the position for the Z gates to control the “search” pattern. Just remember that if you change them in one place, you have to make the same change everywhere else.

Quirk has a way to make a part of the circuit a custom gate. You can also specify custom gates by rotation angles or from a matrix, but I won’t cover that here. The only problem is, once you make a gate, you can’t go back and change it easily. Of course, since everything is stored in the URL (if you haven’t noticed, look in your address bar), you can brute force edit things, if you like.

What’s Next?

These have been three fairly long posts. However, this is just the tiniest tip of the iceberg. There are plenty of gates on Quirk that we haven’t used or talked about. If you use IBM’s real hardware, there’s also a lot more you have to create to do useful things and additional practical considerations, too.

The good news is that there is plenty of material out there on the Internet. The bad news is there isn’t a lot in that middle ground between handwaving generalization and bone-crunching math. What’s more, as I’ve mentioned before, a lot of the generalizations that you’ll hear are oversimplifications that can get in your way of understanding.

If you want to go much further, you are probably going to have to take the math pill. If you know linear algebra and trigonometry, you should be set. If you don’t, take heart because it isn’t as hard as some math out there. You could do worse than start with Kahn Academy.

The other thing I’ve been silent on is how all these qubits exist in physical devices. That’s a fascinating story, too, but just like you don’t need to understand MOSFETS to program a modern CPU, I didn’t think diving into that particular rabbit hole would help gain understanding.

If you are determined and not put off by the math, [Michael Nielsen] has 20 or so videos that are very comprehensive, appropriately titled “Quantum Computing for the Determined.” These are good, but you will need the math. Unfortunately, he never finished the series and the deeper you go, the more the start dealing with proofs and things that you probably should know, but might be more interested in after you get a real understanding.

The IBM User’s Guide has a lot of information that is useful even if you aren’t using their simulator as does the home page for Quirk. IBM also has an interesting example that plays a game using Grover’s algorithm as a web service. Two caveats. Because it is a web-based program, there’s a lot of underpinnings you don’t care about if you are just learning about QC. Also, some of their example code has strings of gates that could be simplified. If you just want to try out the result, you can just open it up from their site.

Finally, MIT has some good examples of how to create complex gates from simpler ones. Sometimes you have to dig a little bit to translate nomenclature between MIT, IBM, and Quirk. It also helps if you learn QASM, which IBM supports but Quirk does not.

Go Forth and Hack

This technology is still in its infancy. While it is hard to get practical devices in your hands, especially when even big labs have fairly small devices, it is easy to work things out in simulation and it is clear there is still more to be developed. The picture to the right is IBM’s newest 50 qubit device. Of course, they aren’t letting you use it on the web. At least, not yet.

To me the danger is the way — deliberately or not — the technology is overhyped. I think some of it is just people generalizing the generalizations they’ve heard somewhere else and you get a little further off the mark each time. Some of it is probably also just marketing hype, which is nothing new. People have to get research grant money and sell stock, after all.

Of course, even if the market is disappointed, the promise that moderately large QC devices will be able to find prime factors quickly (look up Shor’s algorithm) and break military-grade encryption is enough to ensure that those bigger machines will get built. They may get locked away from the likes of us, though.

Without ready access to hardware, I suppose we’ll have to settle for virtual hacking. For today, at least. The hardware is coming and just as in the 1960s no one could guess that computers would be cheap and everywhere, there’s no telling how ubiquitous quantum computing devices will be in fifty years.

Friday Hack Chat: How Do You Collaborate With Hardware?

The world of Open Source software is built on collaboration. In one corner of the world, someone can fix a bug in a piece of software, and push it up to the gits. In another part of the world, someone else can put that fix into the next release, and soon everyone has newer, better software. The Internet, or the ability to rapidly transmit text and binary files, has made this all possible.

Hardware is another story. There’s a financial barrier to entry. Not only do you need a meter and a good iron, you’re probably going to need oscilloscopes, logic analyzers, and a bunch of other expensive tools. You’ll need to buy your BOM. If you’re using a PIC, it might be a good idea to buy the good compiler. Hardware is hard and expensive, and all those software devs who complain don’t know what they’re talking about. Collaborating on hardware is much more difficult than pushing some code up to the cloud.

For this week’s Hack Chat, we’re going to be talking about collaborating on hardware projects. This is a deep dive on how to make collaboration with physical objects work, and this week we’re going to be learning from some of the best.

Our guests for this week’s Hack Chat are Pete Dokter and Toni Klopfenstein of SparkFun Electronics. Pete is formerly the Director of Engineering at SparkFun and now the Brand Ambassador for SparkFun Electronics. He hosts the According to Pete video series expounding on various engineering principles and seriously needs a silverburst Les Paul and a Sunn Model T. Toni is currently the product development manager at SparkFun. She’s served on the Open Source Hardware Association Board and participates in the Open Hardware Summit yearly. In her free time, she spends fifty weeks out of the year finding dust in her art and electronics projects.

During this chat, we’re going to be discussing what makes a collaborative hardware project, how to make distributed development work for your team, and the limits of what you can do with several hardware engineers separated by thousands of miles. This is a hard problem, much harder than a distributed team of software engineers, and a fantastic discussion for all.


Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat is going down Friday, February 9th at noon, Pacific time. Time Zones got you down? Here’s a handy countdown timer!

Click that speech bubble to the left, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Discrete Pong Project Goes Big, Adds a Player

Some projects just take on a life of their own. What started as a pleasant diversion or a simple challenge becomes an obsession, and the next thing you know you’ve built a two-player color Pong game with audio completely from discrete components.

If this one seems familiar, it’s because we were dazzled by its first incarnation last year. As impressive as version 1.0 was, all the more so since it was built using the Manhattan method and seemingly over the course of a weekend, it did have its limitations. [GK] has been refining his design ever since and keeping accurate track of the process, to the tune of 22 pages on the EEVblog forum. We haven’t pored through it all yet, but the state of the project now is certainly worth a look. The original X-Y output to an oscilloscope was swapped out to composite video for a monitor, in both mono and color. This version also allows two people to play head-to-head instead of just battling the machine. It looks like [GK] had to add a couple of blocks worth of real estate to his Manhattan board to accommodate the changes, and he tidied the wiring significantly while he was at it.

It’s a project that keeps on giving, so feast your eyes and learn. We suspect [GK] doesn’t have any plans to finish this soon, but if he does, we can’t wait to see what’s next.

Thanks to [David Gustafik] for reminding us to check back on this one.

Locally Sourced: PLA Adhesive

When I first started getting into 3D printed projects that would require final assembly from multiple parts, I wanted to make sure I had an adhesive that would really hold up. I couldn’t imagine anything worse than spending 10’s of hours printing and assembling something, only to have it fall apart because my adhesive wasn’t up to the task. So I spent a lot of time trolling 3D printing message boards and communities trying to find the best way of gluing PLA. It should come as no surprise that, like everything else in the world, there are a ridiculous number of opinions on the subject.

If you’re printing with ABS, the general wisdom is that solvent welding with acetone is the best bet. You put some acetone on the printed parts, rub them together, and the plastic fuses together. This happens because the ABS melts slightly when exposed to the acetone, so they end up essentially melding into one piece. This sounded like exactly what I wanted, but unfortunately, acetone doesn’t have this same effect on PLA.

After some more research I found people suggesting Weld-On #16, an acrylic adhesive that will actually melt PLA. A little of this applied to the parts, they said, and you can solvent weld PLA just like acetone on ABS. Sure enough, the stuff works great and I’ve used it to put together nearly everything I’ve printed in PLA over the last few years. Only problem is, this stuff is a bit nasty, takes 24 hours to fully cure, and nobody has it locally.

So as an experiment I thought I’d take a look at a few adhesives sold at the local big box retailer and see if I couldn’t find something comparable. Do I need to keep ordering this nasty goop online every time, or can I pick something up off the shelf? More to the point, is solvent welding PLA really any better than just gluing it?

Testing Procedure

To test the different glues, I came up with a simple testing procedure. It’s perhaps not the most scientific of setups, but I think gives me enough information given the relatively stress-free life a 3D printed part lives.

The test setup consists of two rectangles, printed at fairly typical settings (0.2 mm layers, 30% infill), which are glued together at 90 degrees of each other. Through each rectangle is run a metal rod: one of the rods is inserted into two eye hooks installed in an overhead beam, and the other rod is attached to a luggage scale with a short length of chain.

Pulling down on the luggage scale allows me to put tensional force on the two glued pieces, with two possible outcomes: either the printed piece breaks, or the glue releases. For my purposes, I will consider the printed part breaking before the glue releases to be an automatic “win”. Remember, my goal here is only to find if the glue is strong enough to be used for typical 3D printing applications; not an attempt to find the ultimate strength of the bond.

The Glues

I went to the adhesive section of Home Depot and selected a number of glues that advertised they would work on plastics. I avoided anything that cost more than $10 USD, as at that price, I might as well just stick with the Weld-On #16 from Amazon.

For each glue, a pair of rectangles was printed and sanded on the mating surfaces with an 80 grit sanding block. The pieces were then glued as per the instructions, and held together with clamps for the recommended cure time.

Weld-On #16: Designed for PLA Adhesion

As mentioned previously, Weld-On #16 has been my go-to PLA adhesive for years. It has a thick consistency that doesn’t run which is very nice, but it does have that strong chemical smell that acrylic glues tend to have.

Once you apply it to the parts, you can see the top layers of PLA start to melt and get tacky. I usually push the pieces together, rub them back and forth a bit, and then put the part into clamps until everything solidifies. Unfortunately, that’s about 24 hours.

The work time with Weld-On #16 is around 5 minutes, during which time you can reposition the parts easily. This is a big help when trying to line up printed parts that don’t have any pins or features to help keep them oriented correctly.

As expected, this glue preformed very well. The luggage scale maxed out (100 lb), and shortly after that one of the rectangles broke.

Loctite Super Glue Gel: Strong and Fast

This has been my day-to-day cyanoacrylate for awhile now, so I was interested to see how it would work on printed parts. I really like the hard plastic bottle this comes in, as the side mounted “triggers” give you exceptionally fine control over the pressure you put on the internal tube. Combined with the long thin spout, it’s very easy to get this glue down into tight spots.

Being a gel, this glue doesn’t really run once applied. That makes it great for working on vertical surfaces or other hard to reach places. Unfortunately, the gel makes the printed parts extremely slippery. This combined with the roughly 30 second work time makes it difficult to get proper alignment before it sets.

When tested under load, the Loctite Super Glue Gel survived past the breaking point of my test pieces just like Weld-On #16. I’ll admit I was very surprised by this, as I had assumed none of the glues would have been as strong as the solvent welded pieces.

Gorilla Super Glue: Reasonably Strong But Hard to Apply

Truth be told, I actually bought this as a mistake. Originally I thought it was more like the traditional Gorilla glue, and only realized after I got it home that this was yet another cyanoacrylate formula. You’d think I would have noticed that the stuff isn’t brown, but clearly not.

This glue is a little on the watery side, but not too bad. Working time was quite long, on the order of 2 minutes. The instructions don’t call for clamping, but given the long work time I kept it clamped for about 5 minutes to be sure everything had hardened up.

I know it isn’t the most important aspect of this test, but for the sake of completeness I do want to note that the bottle design is a bit annoying. While the spout is the longest out of the all the glues tested, it’s so thick that accurate application is unnecessarily difficult in tight spaces. The nozzle opening is also very wide, so forget about putting this stuff on small pieces.

In the load test, Gorilla Super Glue did quite well, breaking at 87 lb. Even though this glue didn’t end up being the strongest of those tested, the long work time is extremely handy and makes it stand out from the others.

Loctite Plastics Bonding System: Not For PLA

This one is rather interesting, as it is specially formulated for hard to glue plastics and comes in two parts. You first use the “Activator” on the plastic, wait a minute for it to dry, and then apply the glue and clamp the pieces. This seemed a little gimicky to me when I saw it in the store, but figured it was worth a try.

The “Activator” goes on with a felt-tip applicator, and judging by the smell and way it evaporated off the pieces, I’m fairly sure it’s largely isopropyl alcohol. The glue itself is a relatively thick gel and has a working time of about 30 seconds. I was able to reposition the pieces without trouble.

Performance in the load test was the poorest out of all the glues, the bond broke at only 50 lb. To be fair there might be other types of plastic that this product works well on, but PLA is certainly not one of them.

DAP Rapid Fuse: Weak But Longer Working Time

This is a pretty run of the mill “All Purpose” glue that is advertised to be stronger than cyanoacrylate. Unlike most of the other glues tested, this one calls for a half hour of clamp time before reaching full strength.

This turned out to be one of the thicker glues tested, and the claimed 30 seconds work time seems to be a considerable underestimate. In fact, this glue didn’t really start to “stick” until about 2 minutes in. Such a long work time is very forgiving and would make this glue perfect for putting together fiddly little parts.

Unfortunately, DAP Rapid Fuse didn’t do well on the load test. It broke at only 57 lb, the second lowest result. I was particularly disappointed with this one, as I’ve seen this glue specifically mentioned online as being a good choice for PLA parts.

HDX Super Glue: Extremely Strong and (Too) Fast

This is the store-brand cyanoacrylate “Super Glue” from the Home Depot. I got this one because it was very cheap (50 cents per tube, in the 4 pack) and because I thought it would be interesting to test a straight cyanoacrylate glue that wasn’t advertising some special features or formulations.

It’s extremely watery, to the point of literally behaving like water when you put it on the surface to be glued. You need to be very careful about making sure this stuff doesn’t go where you don’t want it. I thought the warning on the back about protecting the work area from spills was odd at first, but not anymore.

The worst part about this glue though is the nearly instantaneous bond. I understand that’s desirable in some situations, but when working with parts that need careful alignment it’s a nightmare. Even for my test pieces, I wasn’t able to get them properly aligned at 90 degrees before the glue had set up and couldn’t be moved. Had this been a multi-part print I was assembling, this could have been a disaster.

In what was probably the biggest surprise of this test however, the basic HDX Super Glue did not fail under the load test. The printed test pieces broke before the bond released, making this an automatic “win”. Working with it is kind of terrible, but credit due on the strength of the bond.

Final Thoughts

Overall, I still think that Weld-On #16 is the best PLA adhesive I’ve personally used. The long work time combined with the high strength bond is simply an ideal combination. Online-only availability, long cure time, and the fact it smells like a chemical factory are bummers to be sure, but not deal-breakers if you want to make absolutely sure your project isn’t going to fail on account of the adhesive used.

That being said, the performance of the Loctite Super Glue Gel really surprised me. Truth be told, I feel a little foolish having used this glue for so long in other applications and only now trying to use it on printed parts. There’s probably a lesson to be learned there about getting stuck in your ways. The work time is a bit short, but otherwise it’s an extremely close alternative to Weld-On #16; close enough that I’ll be using it for most of my PLA gluing from here on out.

Unless I’ve missed something even better? What are you using? Let us know in the comments about your favorite PLA-compatible adhesive. Do we need another round of this PLA adhesive slug fest?

Debugging an Arduino with an Arduino

As every Hackaday reader knows, and tells us at every opportunity in the comments, adding an Arduino to your project instantly makes it twice as cool. But what if, in the course of adding an Arduino to your project, you run into a problem and need to debug the code? What if you could use a second Arduino to debug the first? That would bring your project up to two Arduinos, instantly making it four times as awesome as before you started! Who could say no to such exponential gains?

Debugging an ATTiny85

Not [Wayne Holder], that’s for sure. He writes in to let us know about a project he’s been working on for a while that allows you to debug the execution of code on an Arduino with a second Arduino. In fact, the target chip could even be another AVR series microcontroller such as a the ATTiny85. With his software you can single-step through the code, view and modify values in memory, set breakpoints, and even disassemble the code. Not everything is working fully yet, but what he has so far is very impressive.

The trick is exploiting a feature known as “debugWIRE” that’s included in many AVR microcontrollers. Unfortunately documentation on this feature is hard to come by, but with some work [Wayne] has managed to figure out how most of it works and create an Arduino Sketch that lets the user interact with the target chip using a simple menu system over the serial monitor, similar to the Bus Pirate.

[Wayne] goes into plenty of detail on his site and in the video included after the break, showing many of the functions he’s got working so far in his software against an ATTiny85. If you spend a lot of time working on AVR projects, this looks like something you might want to keep installed on an Arduino in your tool bag for the future.

Debugging microcontroller projects can be a huge time saver when your code starts running on real hardware, but often takes some hacking to get working.

DARPA Enlisting Nemo and Dory to Find You

The ocean is a hostile environment for man-made equipment, no matter its purpose. Whether commercial fishing, scientific research, or military operations, salt water is constantly working to break them all down. The ocean is also home to organisms well-adapted to their environment so DARPA is curious if we can leverage their innate ability to survive. The Persistent Aquatic Living Sensors (yes, our ocean PALS) program is asking for creative ideas on how to use sea life to monitor ocean activity.

Its basic idea is simple: everyday business of life in the ocean are occasionally interrupted by a ship, a submarine, or some other human activity. If this interruption can be inferred from sea life response, getting that data could be much less expensive than building sensors to monitor such activity directly. Everyone who applies to this research program will have the chance to present their own ideas on how to turn this idea into reality.

The program announced it will “study natural and modified organisms” (emphasis ours.) Keeping an open mind to bio-engineering ideas will be interesting, but adding biohacking to the equation also adds to the list of potential problems. While PALS will keep its research within contained facilities, any future military deployment obviously will not. Successful developments in this area will certainly raise eyebrows and face resistance against moving beyond the lab.

But such possibilities are still far away in a future that many never arrive, as is common with DARPA initiatives. Very recently we talked about their interest in brain stimulation and we’ve been fascinated by many DARPA initiatives before that. If PALS takes off, their living sensor nodes might end up face to face with the open-source underwater glider project that won this year’s Hackaday prize.

[via Engadget]

Hacking a Sonoff WiFi Switch

The ESP8266 platform has become so popular that it isn’t just being used in hobby and one-off projects anymore. Companies like Sonoff are basing entire home automation product lines around the inexpensive WiFi card. What this means for most of us is that there’s now an easily hackable and readily available product on the market that’s easily reprogrammed and used with tools that we’ve known about for years now, as [Dan] shows in his latest project.

[Dan] has an aquaponics setup in his home, and needs some automation to run the lights. Reaching for a Sonoff was an easy way to get this done, but the out-of-the-box device can only be programmed in the simplest of ways. To get more control over the unit, he wired a USB-to-Serial UART to the female headers on the board and got to programming it.

The upgraded devices are fully programmable and customizable now, and this would be a great hack for anyone looking to get more out of a Sonoff switch. A lot of the work is already done, like building a safe enclosure, wiring it, and getting it to look halfway decent. All that needs to be done is a little bit of programming. Of course, if you’d like to roll out your own home automation setup from scratch that can do everything from opening the garage door to alerting you when your dog barks, that’s doable too. You’ll just need a little more hardware.

Eating a QR Code May Save Your Life Someday

QR codes are easy to produce, resistant to damage, and can hold a considerable amount of data. But generally speaking, eating them has no practical purpose. Unfortunately the human digestive tract lacks the ability to interpret barcodes, 2D or otherwise. But thanks to the University of Copenhagen, that may soon change.

A new paper featured in the International Journal of Pharmaceutics details research being done to print QR codes with ink that contains medicine. The mixture of medicines in the ink can be tailored to each individual patient, and the QR code itself can contain information about who the drugs were mixed for. With a standard QR reader application on their smartphone, nurses and care givers can scan the medicine itself and know they are giving it to the right person; cutting down the risk of giving patients the wrong medication.

The process involves using a specialized inkjet printer to deposit the medicine-infused ink on a white edible substrate. In testing, the substrate held up to rough handling and harsh conditions while still keeping the QR code legible; an important test if this technology is to make the leap from research laboratory to real-world hospitals.

In the future the researchers hope the edible substrate can be produced and sent to medical centers, and that the medicinal ink itself will be printable on standard inkjet printers. If different medicines were loaded into the printer as different colors, it should even be possible to mix customized drug “cocktails” through software. Like many research projects it seems likely the real-world application of the technology won’t be as easy as the researchers hope, but it’s a fascinating take on the traditional method of dispersing medication.

QR codes have long been a favorite of the hacker community. From recovering data from partial codes to using them to tunnel TCP/IP, we’ve seen our fair share of QR hacks over the years.

[Thanks to Qes for the tip]

ESP32, We Have Ways to Make You Talk

One of our favorite scenes from the [James Bond] franchise is the classic exchange between [Goldfinger] and [Bond]. [Connery] (the One True Bond) says, “You expect me to talk?” And the reply is, “No Mr. Bond, I expect you to die!” When it comes to the ESP32, though, apparently [XTronical] expects it to talk. He posted a library to simplify playing WAV files on the ESP32. There is also a video worth watching, below.

Actually, you might want to back up to his previous post where he connects a speaker via one of the digital to analog converters on the board. In that post, he just pushes out a few simple waveforms, but the hardware is the same setup he uses for playing the WAV files.

By wrapping up the WAV code in a library, [XTronical] makes the actual playback simple. Here’s the core of his simple example:

void loop() {
static uint32_t i=0; // simple counter to output
if(ForceWithYou.Completed) // if completed playing, play again
    DacAudio.PlayWav(&ForceWithYou); // play the wav (pass the wav class object created at top of code
    Serial.println(i); // print out the value of i
    i++; // increment the value of i

Not very hard, but, of course, the heavy lifting is hidden in the two objects PlayWav and ForceWithYou. The video explains how you can add more, but you can probably guess, too. The short version is he uses Audacity to prepare the WAV file and then a hex editor to get the bytes into an array. Since many of us use Linux or Cygwin, we might have been tempted to use od or hexdump, but however you do it, it has to wind up in an array.

If you want to experiment more with waveform generation, [Elliot Williams] did a good piece on that. You might also get some ideas from our signal generator.

February 06 2018

Printed Adapter Teaches an Old Ninja New Tricks

Do you like change for the sake of change? Are you incapable of leaving something in a known and working state, and would rather fiddle endlessly with it? Are you unconcerned about introducing arbitrary compatibility issues into your seemingly straight-forward product line? If you answered “Yes” to any of those questions, have we got the job for you! You can become a product engineer, and spend your days confounding customers who labor under the unrealistic expectation that a product they purchased in the past would still work with seemingly identical accessories offered by the same company a few years down the line. If interested please report to the recruitment office, located in the darkest depths of Hell.

A 2D representation of the adapter in Fusion 360

Until the world is rid of arbitrary limitations in consumer hardware, we’ll keep chronicling the exploits of brave warriors like [Alex Whittemore], who take such matters into their own hands. When he realized that the blades for his newer model Ninja food processor didn’t work on the older motor simply because the spline was a different size, he set out to design and print an adapter to re-unify the Ninja product line.

[Alex] tried taking a picture of the spline and importing that into Fusion 360, but in the end found it was more trouble than it was worth. As is the case with many printed part success stories, he ended up spending some intimate time with a pair of calipers to get the design where he wanted it. Once broken down into its core geometric components (a group of cylinders interconnected with arches), it didn’t take as long as he feared. In the end the adapter may come out a bit tighter than necessary depending on the printer, but that’s nothing a few swift whacks with a rubber mallet can’t fix.

This project is a perfect example of a hack that would be much harder (but not impossible) without having access to a 3D printer. While you could create this spline adapter by other means, we certainly wouldn’t want to. Especially if you’re trying to make more than one of them. Small runs of highly-specialized objects is where 3D printing really shines.

This is an entry in Hackaday’s

Repairs You Can Print contest

The twenty best projects will receive $100 in Tindie credit, and for the best projects by a Student or Organization, we’ve got two brand-new Prusa i3 MK3 printers. With a printer like that, you’ll be breaking stuff around the house just to have an excuse to make replacement parts.


Water Cooling a 3D Printer

It may seem like a paradox, but one of the most important things you have to do to a 3D printer’s hot end is to keep it cool. That seems funny, because the idea is to heat up plastic, but you really only want to heat it up just before it extrudes. If you heat it up too early, you’ll get jams. That’s why nearly all hot ends have some sort of fan cooling. However, lately we have seen announcements and crowd-funding campaigns that make it look like water cooling will be more popular than ever this year. Don’t want to buy a new hot end? [Dui ni shuo de dui] will show you how to easily convert an E3D-style hot end to water cooling with a quick reversible hack.

That popular style of hot end has a heat sink with circular fins. The mod puts two O-rings on the fins and uses them to seal a piece of silicone tubing. The tubing has holes for fittings and then it is nothing to pump water through the fittings and around the heat sink. The whole thing cost about $14 (exclusive of the hot end) and you could probably get by for less if you wanted to.

[Dui] mentions that you don’t need a super powerful pump. We suspect too much pressure in the system would make it much more likely to leak, so this is a case where less is almost certainly more. In fact, [Dui’s] first few attempts had some leakage, so you’ll want to carefully test before you install everything back into the printer.

You might wonder if you need water cooling when fans work fine. Well, first of all, when has that ever stopped any of us? But second, apparently, as you increase flow rate — either for extrusion speed or to use a larger nozzle or both — you have to increase temperatures and this can tax the normal cooling system. That causes clogs and the water cooling is much more efficient.

Water cooling is nothing new for PCs, of course. We’ve seen water-cooled LED lights, too. We’ve even seen chips directly cooled with water.

February 04 2018

Benchtop Fume Extractor Cuts the Cord, Clears the Air

What good is safety gear that isn’t used because it’s annoying and gets in the way of getting the job at hand completed? None, really, and the solder fume extractor is one item that never seems to live in harmony with your workspace. They’re often noisy, they obstruct your vision, and a power cord draped across your bench is a sure way to ruin your soldering zen.

To fix those problems, [Nate] has built a nice battery powered solder fume extractor that’s so low profile and so quiet, you won’t mind sharing a bench with it. Based on a standard 80-mm case fan, the extractor has a built-in 18650 battery for power and a USB charging port. There are nice little features, like a speed control and a low-battery indicator. The fan mounts to a pair of custom PCBs, which form the feet for the fan. [Nate] claims to have run the fan for 12 hours straight on battery before needing a charge, and that it’s so quiet he needs to add a power indicator to the next version. Also making an appearance in rev 2 will be a carbon filter to catch the fumes, but as [Nate] notes, better to spread them around for now than let them go directly up his nose.

Are you in the hacking arts for the long haul? Let’s hope so. If you are, make sure you’re up on the basics of mitigating inhalation hazards.

Repairs You Can Print: Nintendo 3DS XL Lives Again!

Handheld game consoles have a hard life, and even the most well-built models can sometimes fail. The Nintendo 3DS XL, for example, can fail at its hinge, which is what happened to the one owned by [Mark]. Would he fix the hinge? No, he had a far simpler if a little less flexible solution, a 3D-printed bracket that clips over the whole device.

Sometimes the best pieces of work are also the simplest ones, and this one certainly fits that bill on both counts. When your console dies, you want it fixed, and though this doesn’t extend as far as providing a working hinge action it should allow you to play without further damaging anything. It’s not impossible to imagine that it could be made to incorporate a flexible zig-zag section to produce a closeable hinge, but if your Nintendo is broken you’ll care little for such niceties. The project can be downloaded from its Thingiverse page.

A common failure that we’d expect to accompany a broken hinge would be a faulty flexible ribbon cable. Fortunately, those are fixable on the 3DS, too.

A Few Laser-Cut Cases For Your SBCs

Single-board computers, usually featuring ARM processors, have revolutionized the world of the hardware hacker over the last decade. The computing power you would have found in a desktop computer not so long ago, mounted on a small PCB and powered from a mobile phone charger.

With a few notable exceptions though, these single board computers are just that, boards. No cases in the pack, which has, of course, spawned a huge aftermarket of commercial offerings and a pile of homemade ones of varying sophistication. If these homemade offerings are your fancy then today’s link may be of interest, some very well-designed laser-cut cases from [Nick Smith] for a selection of popular and less well-known boards.

The Orange Pi Lite and Raspberry Pi Zero are both familiar enough, but one of the delights of writing for Hackaday reveals itself in the discovery of the more esoteric Marvell ESPRESSObin, an SBC with multiple network ports and serial ATA.

Are cases your passion? Step back in time for our round-up of case designs for the first Raspberry Pi.

Via Hacker News.


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