Gradient Infill Puts More Plastic Where You Want It

It is always tricky setting the infill for a 3D printed part. High infill parts are strong but take longer to print, while low infill prints take less time, but are weaker internally and in danger of surface layer droop between the infill pattern. [Stephan] has a better answer: gradient infill. You can see a video below and find his Python code on GitHub.

The idea is simple enough. In most cases, parts under stress see higher stress near the surface. Putting more material there will make the part stronger than adding plastic in places where the stress is lower. [Stephan] has done finite element analysis to determine an optimal infill pattern before, but this is somewhat difficult to do. Since the majority of parts can follow the more at the edges and less at the center rule, gradient infill makes sense except for a few special cases.

Of course, the real question is: how do you create parts with this type of infill? Some slicers have infill settings that can almost get you there. However, the setup for them isn’t easy. For example, KISSSlicer’s paid version will take a grayscale image to set the infill density. [Stephan] noticed, though, that Cura — and probably most other slicers — put comments in the G-code to show where different features such as infill start. By changing the extrusion amount during infill, you can use the same basic pattern, but still, get the gradient you want.

He wrote a simple program to postprocess the G-code before it is sent to the printer. He computes the distance from the outside of the part and based on that changes the amount of extrusion. This works because of an unusual type of infill he uses that is already in small line segments. However, for more conventional infill patterns, the lines are long, so his program has to chop the lines into shorter segments and then apply the algorithm. This makes for a larger file, of course.

There are a few stipulations. You need to have walls print before infill and you need to be set for relative extrusion. If your slicer doesn’t emit comments to mark where infill starts and stops, that’s going to be a problem. Even then, if the comments aren’t the same as Cura’s, you’ll probably need to change the code to suit. Or just use Cura for slicing.

The test results were good. The parts were stronger, although in some cases, simply increasing the infill would get you the same result. As [Stephan] notes, it may not be perfect, but it is useful for many parts.

We aren’t strangers to postprocessing G code. For some jobs, you just need to make your own G-code, anyway.

Posted in 3d Printer hacks, 3d printing, cura, g-code, gcode, infill | Leave a comment

Random Numbers From Outer Space

Need a random number? Sure, you could just roll a die, but if you do, you might invite laughter from nearby quantum enthusiasts. If it’s truly, unpredictably random numbers you need, look no farther than the background radiation constantly bombarding us from the safety of its celestial hideout.

In a rare but much appreciated break from the Nixie tube norm of clock making, [Alpha-Phoenix] has designed a muon-powered random number generator around that warm, vintage glow. Muons are subatomic particles that are like electrons, but much heavier, and are created when pions enter the atmosphere and undergo radioactive decay. The Geiger-Müller tube, mainstay of Geiger counters the world over, detects these incoming muons and uses them to generate the number.

Inside the box, a 555 in astable mode drives a decade counter, which outputs the numbers 0-9 sequentially on the Nixie via beefy transistors. While the G-M tube waits for muons, the numbers just cycle through repeatedly, looking pretty. When a muon hits the tube, a second 555 tells the decade counter to stop immediately. Bingo, you have your random number! The only trouble we can see with this method is that if you need a number right away, you might have to go get a banana and wave it near the G-M tube.

Whether this all makes sense or not, you should check out [Alpha-Phoenix]’s project video, which is as entertaining as it is informative. He’s planning a follow-up video focused on the randomness of the G-M tube, so look out for that.

Looking for a cheaper way to catch your random numbers? You can do it with a fish tank, some air pumps, and a sprinkle of OpenCV.

Via r/electronics

Posted in 555, classic hacks, decade counter, Geiger tube, muon, nixie, random number, random number generator | Leave a comment

Electric Unicorn Is Our Kind Of Rideable

When [Charlyn] took a unicorn rocking horse in to work, it was an instant hit. Naturally, the people wanted more, and suggested it needed electric propulsion. Naturally, she rose to the challenge, and Rocky the Unicorn got a motorized upgrade.

The build consists of a frame built out of PVC pipes, hooked up with Formufit fittings. These are a great way to build useful structures out of PVC pipe, and made the build a cinch. The frame has a footrests for the rider, and the rocking horse already has a comfortable seat. For propulsion, a hoverboard is installed in the base, with the frame sporting a pair of casters to avoid tip over. Twin PVC handles are used to interface with the footplate of the hoverboard, allowing the user to drive and steer, as well as turn on the spot. A bouquet of fake flowers round out the aesthetic and hide some of the zipties.

It goes to show that PVC pipe can be an excellent material for quick, fun projects – all you need is the right fittings to make it all happen! It’s also fun to see a hoverboard used in such a way that doesn’t end with severe injuries.  Unicorns always bring a nice flair to a project, too. Video after the break.

Posted in hoverboard, rideable, toy hacks, transportation hacks, unicorn | Leave a comment

Testing Your Grit: Tales of Hacking in Difficult Situations

What’s your work area like? Perhaps you’re mostly a software person, used to the carpeted land of cubicles or shared workspaces, with their stand-up desks and subdued lighting. Or maybe you’ve got a lab bench somewhere, covered with tools and instruments. You might be more of a workshop person, in a cavernous bay filled with machine tools and racks of raw material. Wherever you work, chances are pretty good that someone is paying good money to keep a roof over your head, keeping the temperature relatively comfortable, and making sure you have access to the tools and materials you need to get the job done. It’s just good business sense.

Now, imagine you’ve lost all that. Your cushy workspace has been stripped away, and you’ve got to figure out how to get your job done despite having access to nothing but a few basic tools and supplies and your own wits. Can you do it? Most of us would answer “Yes,” but how many of us have ever tested ourselves like that? Someone who has tested her engineering chops under difficult conditions — and continues to do so regularly — is Laurel Cummings, who stopped by the 2019 Hackaday Superconference to tell us all about her field-expedient life with a talk aptly titled, “When It Rains, It Pours”.

Trip from Hell

Laurel shared quite a bit of her background in the talk, which really showed how the circumstances of her life prepared her for her current gig. Right after finishing her EE degree she decided to take a little break from the action by helping her dad move his boat down the east coast of the United States. The short, relaxing jaunt she expected evaporated soon after setting sail when the boat broke down in about as many ways as a boat can. She soon found herself hanging upside down in the engine compartment trying to solder the regulator from a truck alternator into place with a butane torch, sewing a torn sail back together in the dark, and being towed back into port by the Coast Guard.

After that experience, a nice, safe office job would seem to be the logical choice, but instead Laurel went to work for Building Momentum, a technology development and education outfit based in Virginia. The company’s major clients are active-duty military units and disaster-response NGOs, leading Laurel to places like Kuwait during historic floods, or to a Marine Corps base after Hurricane Florence drenched North Carolina in 2018.

Watney Your Troubles Away

There she learned the importance of delivering something — anything — within 24 hours of arriving, which she stressed is important for establishing your bona fides as someone who can help rather than hinder. For the Marines, her team rapidly identified a problem — the base’s many emergency generators all had to be checked manually for fuel use — and built a version 0.1 solution, which ended up looking like a breadboard project in a plastic bag. But it was enough to get a toe in the door, giving her team the cachet needed to improve the design and pitch in elsewhere.

Full life cycle of the fuel gauge project

In her talk, Laurel outlined a simple but sensible process for attacking problems quickly. It’s designed for austere conditions, but it applies to everyday engineering just as well. Her approach to identifying the problems and deciding which ones to attack stuck out the most to me; to accomplish this, she suggests listing all the problems that the clients relate and then organizing them into a sort of “tag cloud” of similar issues. That helps find the real root issues and identifies which ones to attack first to deliver the most bang for the buck.

It sounds like Laurel has found a challenging and exciting work environment that’s a bit out of the ordinary. But when you think about it, a lot of engineers end up in similar situations. A lot of engineering gets done on remote mountaintops, at dams and in jungles, and in the bowels of ships far from shore. In those situations, one rapidly learns that if you didn’t bring it with you, it might as well not exist, and you have to make do with what you’ve got. Chance favors the prepared mind in those situations, and it sounds like Laurel has a leg up on her desk-bound colleagues in that regard.

[Main image via @BrucePerens]

Posted in 2019 Hackaday Superconference, austere, cons, disaster, emergency, FIELD | Leave a comment

Teardown: BilBot Bluetooth Robot

Historically, the subject of our January teardown has been a piece of high-tech holiday lighting from the clearance rack; after all, they can usually be picked up for pocket change once the trucks full of Valentine’s Day merchandise start pulling up around the back of your local Big Box retailer. But this year, we’ve got something a little different.

Today we’re looking at the BilBot Bluetooth robot, which over the holidays was being sold at Five Below for (you guessed it) just $5 USD. These were clearly something the company hoped to sell a lot of, with stacks of the little two-wheeled bots in your choice of white and yellow livery right by the front door. With wireless control from your iOS or Android device, and intriguing features like voice command, I’d be willing to bet they managed to move quite a few of these at such a low price.

For folks like us, it can be hard to wrap our minds around a product like this. It must have a Bluetooth radio, some kind of motor controller, and of course the motors and gears themselves. Yet they can sell it for the price of a budget hamburger and still turn a profit. If you wanted to pick up barebones robotics platform, with just a couple gear motors and some wheels, it would cost more than that. The economies of scale are a hell of a thing.

Which made me wonder, could hackers take advantage of this ultra-cheap robot for our own purposes? It’s pretty much a given that the software for this robot will be terrible, and that whatever control electronics live inside it will be marginal at best. But what if we write those off and just look at the BilBot as a two-wheeled platform to carry our own electronics? It’s certainly worth $5 to find out.

Getting Geared Up

So what do you get for your hard earned five spot? Upon cracking open the BilBot’s case, we see the gearbox down at the bottom, a small PCB up in the “head”, and…not a whole lot else. Of course, this shouldn’t come as much surprise. To get the cost down this far, the hardware needs to be as minimal as possible.

That said, the gearbox isn’t half bad. It’s got plastic gears of course, and with brushed motors and no encoders you won’t get any positioning feedback, but you could say the same about plenty of low-cost robotic platforms that are out there. You won’t be taking it off-road, but this setup will have no problem scooting around your workbench. Though I would suggest adding some grip to the wheels; which could be as easy as finding properly sized rubber bands to fit around them.

The BilBot’s Brain

Removing the two screws holding in the single PCB, we can get a good look at the electronics in their entirety. Originally I’d hoped to find a relatively standard Bluetooth module inside the BilBot, as we’ve seen in previous teardowns. But the Bluetooth chip used in the BilBot, a JL E90005-9BO, seems to be something of a mystery. I haven’t been able to find any mention of it in the usual places, and would be interested to hear if anyone in the audience has ever run across one in the past.

Luckily the other chip on the board, an MX1508L, is another story entirely. This is a fairly common dual H bridge DC motor driver for which the datasheet is readily available. This chip could easily be connected to your microcontroller of choice, and there’s plenty of sample code floating around online that shows how to interface with it.

One would simply need to cut the traces between the MX1508L and the Bluetooth chip, and then wire it up to their own MCU to take control of the BilBot hardware. Slapping an ESP8266 into this bot and converting it to WiFi control would be absolutely trival, and with all that empty space inside its cute little body, there’s plenty of room to add in new sensors, batteries, or whatever else you could come up with.

It’s also worth noting that the BilBot is one of the very few products I’ve seen in the FCC ID database that actually has its circuit schematics available for download. Not that it’s a particularly complex PCB, of course, but there’s no such thing as having too much information when trying to reverse engineer a gadget.

Speaking the BilBot’s Language

Obviously hardware hacking is what we’re all about here, but for the sake of argument, let’s say you wanted to take a more nuanced approach with the BilBot. As the little fellow is designed to be controlled remotely over Bluetooth, it would seem reasonable enough that we could capitalize on that feature and take command of the bot without having to crack open the case at all.

I should start by saying that I refused to actually install the BilBot’s software on any of my devices, and I would advise anyone else who might be experimenting with this bot to do the same. The application cannot be found in the Google Play Store, and instead you are expected to scan a QR code in the manual which points you to an IP address in Hangzhou where the APK can be downloaded for sideloading. Yeah, no thanks.

That said, I did download the 30 MB (!) APK on my computer and used apktool to have a look around inside. I didn’t see anything obviously nefarious, but I certainly don’t claim to be an Android security expert. It just seems exceedingly suspicious that this is how they would distribute the software for their product.

Halfhearted security analysis aside, poking around the application’s source code did give me a pretty good idea about how it works. Essentially moving the virtual joystick around or speaking voice commands into the application chains together byte sequences which eventually get fired off towards the Bilbot over a simple Bluetooth serial connection. That means writing a library to get the robot moving should be very simple, should anyone feel so inclined.

As a proof of concept, you can see here how I am able to connect (with no authentication) to the robot using bettercap, enumerate the writable Service Characteristic, and send a few bytes down the line.

The result is the bot lurching backwards an inch or so. If you were particularly bored, you could probably brute force the byte sequences like this to figure out how to control the motors, but would-be BilBot library writers will likely find that lifting them from the application is a much more efficient use of their time.

Bot on a Budget

In short, I believe the BilBot is a fantastic deal at $5. Not for its intended purpose, mind you, but as an ultra cheap robotics platform that’s just begging to get upgraded. Whether you want to write a Python library to control an army of stock BilBots, or rip its brain in half and augment it with a beefy MCU and all the trimmings, you could do worse than stocking up on these little guys.

One thing I did notice on my particular BilBot, and it could have been a fluke, is that there were no screws holding the gearbox together. So after a few seconds of driving around, the box would pop open and the gears would no longer mesh. Finding a few suitably small screws was no problem, but it does make me wonder how many of these bots were deemed DOA when they sprung a sprocket on Christmas morn.

But really, what do you expect for $5?

Posted in apktool, bettercap, ble, bluetooth, h-bridge motor controller, Hackaday Columns, MX1508L, repurpose, robotics, teardown, toy hacks | Leave a comment

RasterCarve Converts Images to CNC

CNC machines are an essential part of the hacker’s toolset. These computer-controlled cutters of wood, metal and other materials can translate a design into a prototype in short order, making the process of iterating a project much easier. However, the software to create these designs can be expensive, so [Franklin Wei] decided to write his own. In particular, he decided to write his own program to engrave images, converting a photo into a toolpath that can be cut. The result is RasterCarve, a web app that converts an image into a GCode that can be fed into a CNC machine.

The motivation for this project was to learn how to do it, but also frustration at the cost of software such as PhotoVCarve. Costing $149, this program does much the same as the one written by [Wei], albeit with a number of additional bells and whistles. He does an excellent job of describing how the conversion process works: his code creates a series of paths across the image, then converts the color of each pixel into a depth: The darker the image, the deeper the cut.

He also describes the process of taking this simple code and converting it into a Javascript web app, a process that has driven many a programmer to madness. It just goes to show that, although using other people’s stuff is fine, it often makes sense to try and do it yourself.

Posted in cnc, cnc hacks, javascript, render | Leave a comment

Hackaday Links: January 19, 2020

We’ve seen some interesting pitches in personal ads before, but this one takes the cake. Japanese billionaire Yusaku Maezawa is looking for a date to go along with him on his paid trip to the Moon, with the hope of finding a life partner. Maezawa is slated to be SpaceX’s first commercial lunar flyby customer, and will make the trip no earlier than 2023. That should give him plenty of time to go through the 20,000 applications he received from single women 20 and older with bright personalities and positive attitudes. And he should have plenty of time to make an awesome mixtape for the ride.

Imagine snooping through your kid’s garbage can only to find a used syringe lying in there. Most of us would likely be able to tell that the syringe once contained thermal compound or solder paste and be suitably proud of the little chip off the block, but apparently Cooler Master has fielded enough calls from panicked normie parents that they decided to change the design of their applicators. Given the design of the new applicator we doubt that’s really the reason, but it’s a good marketing story, and we can totally see how someone could mistake the old applicator for something illicit.

It looks as though SpaceX could be getting itself into legal trouble with its Starlink launches. Or more correctly, the FCC might, having apparently violated the National Environmental Policy Act, a Nixon-era law that requires government agencies to consider the environmental impact of any projects they approve. The Federal Communications Commission has been using a loophole in the law to claim a “categorical exemption” from these reviews when approving communications projects, particularly space-based projects. It’s not clear whether space is legally considered part of the environment, so the lawyers are hashing that out. If the FCC gets sued and loses, it’s not clear what happens to the existing Starlink satellites or future launches. Stay tuned for details.

Don’t forget that the Open Hardware Summit is coming soon. The 2020 meeting is the 10th anniversary of the confab, to be held on March 13 in New York. Hackaday is, of course, a proud sponsor of the conference, and our own Sophi Kravtiz will be the keynote speaker! Get your tickets soon.

Tired of off-loading data manipulation and analysis tasks to R in your Python programs? Then you’re probably already aware of Pandas, the Python library that converts data into dataframe objects for easier manipulation. Pandas has (have?) been in pre-release for years, but there’s now a legit 1.0.0 release candidate available. Now might be the time for you Python data mungers to get onboard the Pandas Express.

And finally, the Consumer Electronics Show is a yearly gift to anyone in the tech media, providing as it does so many examples of outrageous uses for the latest technology. To wit, we have LuluPet, the world’s first feces-analyzing cat litter box. LuluPet uses a built-in camera along with IR sensors and an “AI chip” to monitor your cat’s dookie and provide an alert if anything looks awry. On the one hand, inspecting cat poop is a job we’d love to outsource, but on the other hand, most cats we know are quick to cover the evidence of their excretions with kitty litter, leaving a clay-encrusted blob rather than the turds with defined borders that would seem to be needed for image recognition to do its job. We’ll reserve judgment on this one until we see a review.

Posted in feces, Hackaday Columns, Hackaday links, open hardware, Pandas, personal ads, python, R, space tourism, SpaceX, Starlink | Leave a comment

Be Still, My Animatronic Heart

Fair warning for the squeamish: some versions of [Will Cogley]’s animatronic heart are realistic enough that you might not want to watch the video below. That’d be a shame though, because he really put a lot of effort into the build, and the results have a lot to teach about mimicking the movements of living things.

As for why one would need an animatronic heart, we’re not sure. [Will] mentions no specific use case for it, although we can think of a few. With the Day of Compulsory Romance fast approaching, the fabric-wrapped version would make a great gift for the one who stole your heart, while the silicone-enrobed one could be used as a movie prop or an awesome prank. Whatever the reason, [Will]’s build is a case study in incremental development. He started with a design using a single continuous-rotation servo, which powered four 3D-printed paddles from a common crank. The four paddles somewhat mimicked the movements of the four chambers of the heart, but the effect wasn’t quite convincing. The next design used two servos and complex parallelogram linkages to expand each side of the heart in turn. It was closer, but still not quite right.

After carefully watching footage of a beating heart, [Will] decided that his mechanism needed to imitate the rapid systolic contraction and slow diastolic expansion characteristic of a real heart. To achieve this, his final design has three servos plus an Arduino for motion control. Slipped into a detailed silicone jacket, the look is very realistic. Check out the video below if you dare.

We’ve seen plenty of animatronic body parts before, from eyes to hands to entire faces. This might be the first time we’ve seen an animatronic version of an internal organ, though.

Posted in animatronic, arduino, beating, diastole, heart, misc hacks, organ, robots hacks, servo, systole | Leave a comment

Binary Advent Calendar Does More With Fewer Doors

[John] sent this one in to us a little bit after Christmas, but we’ll give him a pass because it’s so beautiful. Think of it this way: now you have almost a full year to make a binary advent calendar of your own before December 1st rolls around again.

Normal advent calendars are pretty cool, especially when there is chocolate behind all 24 doors. But is it really a representational ramp-up if you never get more than one chocolate each day? [John] doesn’t think so. The economics of his binary advent calendar are a bit magical, much like the holiday season itself. Most days you’ll get two pieces of chocolate instead of one, and many days you’ll get three. That is, as long as you opened the right doors.

A momentary switch hidden behind the hinge of each door tells the Arduino clone when it’s been opened. The Arduino checks your binary counting abilities, and if you’re right, a servo moves a gate forward and dispenses one chocolate ball per opened door. We love the simplicity of the dispensing mechanism — the doors are designed with a ceiling that keeps non-qualifying chocolates in their channels until their flag comes up.

[John] is working out the kinks before he releases this into the wild. For now, you can get a taste in the demo video featuring a bite-sized explanation. If you don’t like chocolate, maybe this blinky advent calendar will light you up inside.

Posted in advent, advent calendar, binary, binary calendar, chocolate, Holiday Hacks | Leave a comment

Experiments In Soft Robotics

[Arnav Wagh] has been doing some cool experiments in soft robotics using his home 3D printer.

Soft robots have a lot of advantages, but as [Arnav] points out on his website, it’s pretty hard to get started in the same way as one might with another type of project. You can’t necessarily go on Amazon and order a ten pack of soft robot actuators in the way you can Arduinos.

The project started by imitating other projects. First he copied the universities who have done work in this arena by casting soft silicone actuators. He notes the same things that they did, that they’re difficult to produce and prone to punctures. Next he tried painting foam with silicone, which worked, but it was still prone to punctures, and there was a consensus that it was creepy. He finally had a breakthrough playing with origami shapes. After some iteration he was able to print them reliably with an Ultimaker.

Finally to get it into the “easy to hack together on a weekend” range he was looking for: he designed it to be VEX compatible. You can see them moving in the video after the break.

Posted in 3d printing, flxo, programmable air, robot, robots hacks, soft robotics, TPU | Leave a comment