Counting objects is an ideal task for automation, and when focusing on a single type of object, there are many effective solutions. But what if you need to count hundreds of different objects? That’s the challenge [Christopher] tackled with his latest addition to his impressive automation projects. (Video, embedded below.)

[Christopher] has released a series of videos showcasing a containerized counting system for various fasteners, available on his YouTube channel. Previously, he built remarkable devices to count and sort fastener hardware for automated packaging, but those systems were designed for a single fastener type. He effectively highlights the vast complexity of the fastener ecosystem, where each diameter has dozens of lengths, multiple finishes, various head shapes, and more.

To address this, he developed a machine that accepts standardized containers of fastener hardware. These uniform boxes can hold anything from a small M2 countersunk screw to a large M8 cap head bolt and everything in between. To identify the loaded box and determine the appropriate operations, the machine features an RFID reader that scans each box’s unique tag.

Once a box is loaded, the machine tilts it to begin counting fasteners using a clever combination of moving platforms, an optical sensor, and gravity. A shelf first pushes a random number of fasteners onto an adjustable ledge. A second moving platform then sweeps excess fasteners off, leaving only those properly aligned. It’s no surprise this system has nine degrees of freedom. The ledge then moves into view of a sensor from a flatbed scanner, which detects object locations with an impressive 0.04 mm resolution across its length—remarkable for such an affordable sensor. At this point, the system knows how many fasteners are on the ledge. If the count exceeds the desired number, a sloped opening allows the ledge to lift just high enough to release the correct amount, ensuring precision.

The ingenuity continues after the initial count. A secondary counting method uses weight, with a load cell connected to the bin where fasteners drop. A clever over-center mechanism decouples the tilting system from the load cell to ensure accurate readings. We love automation projects, and this one incorporates so many ingenious design elements that it’s sure to inspire others for their future endeavors.

There was a time when print-in-place moving parts were a curiosity, but [Tomek] shows that things are now at a point where a hand-cranked turbine blower with integrated planetary gears can be entirely 3D printed. Some assembly is needed, but there is no added hardware beyond the printed parts. The blower is capable of decent airflow and can probably be optimized even further. Have a look at it work in the video below.

Every piece being 3D printed brings a few advantages. Prefer the hand crank on the other side? Simply mirror everything. Want a bigger version? Just scale everything up. Because all of the fasteners are printed as well as the parts, there’s no worry about external hardware no longer fitting oversized holes after scaling things up (scaling down might run into issues with tolerances, but if you manage an extra-small version, we’d love to hear about it).

There are a few good tips that are worth keeping in mind when it comes to print-in-place assemblies with moving parts. First, changing the seam location for each layer to ‘Random’ helps make moving parts smoother. This helps prevent the formation of a seam line, which can act as a little speed bump that gets in the way of smooth movement.

The other thing that helps is lubrication. A plastic-safe lubricant like PTFE-based Super Lube is a handy thing to have around the workshop and does wonders for smoothing out the action of 3D-printed moving parts. And we can attest that rubbing candle wax on mating surfaces works pretty well in a pinch.

One downside is that the blower is noisy in operation. 3D printed gears (and even printed bearings) can be effective, but do contribute to a distinct lack of silence compared to their purpose-built versions.

Still, a device like this is a sign of how far 3D printing has come, and how it enables projects that would otherwise remain an idea in a notebook. We do love 3D-printed gears.

Whatever your day job, many of us would love to jump behind the controls of a dump truck for a lark. In the real world, that takes training and expertise and the opportunity is denied to many of us. However, you can live out those dreams on your desk with this 3D-printed build from [ProfessorBoots.]

The build exists as two separate parts—the tractor, and the trailer. The tractor is effectively a fairly straightforward custom RC build, albeit with a few additional features to make it fit for purpose. It’s got six wheels as befitting a proper semi, and it has a nifty retractable magnetic hitch mechanism. This lets it hook up to various trailers and unhitch from them as desired, all from a press on the remote. The hitch also has provision for power and control lines that control whatever trailer happens to be attached.

As for the trailer, it’s a side-dumper that can drop its load to the left or right as desired. The dumping is controlled via a linear actuator using a small DC motor and a threaded rod. A servo controls a sliding locking mechanism which determines whether the truck dumps to the left or right as the linear actuator rises up.

The design video covers the 3D printed design as well as some great action shots of the dump truck doing its thing. We’ve featured some builds from [ProfessorBoots] before, too, like this neat 3D-printed forklift . Video after the break.

[Anton Gaia]’s SPIRAL sculpture resembles an organizer or modern shelving unit, but what’s really interesting is how it goes together. It’s made entirely from assembling copies of a single component (two, if you count the short ‘end pieces’ as separate) without a fastener in sight. [Anton] made the 3D model available, so check it out for yourself!

The ends of each part form a tight, spiral-shaped joint when assembled with its neighbors. Parts connect solely to themselves without any need of fasteners or adhesives.

The end result is secure, scalable, and with a harmonious structure that is very pleasing to look at. Small wonder [Anton] used it as the basis for artistic work. You can see more pictures here.

The design of the joint is based on the golden spiral (which it turns out is also be a pretty useful chicken coop architecture.)

The parts lend themselves quite well to 3D printing, and we’d like to take a moment to appreciate that [Anton] shared the .step file instead of just an STL. STEP (or STP) files can be imported meaningfully into CAD programs, making it much easier to incorporate the design into one’s own work. STEP is also supported natively in many 3D printer slicers, so there’s no need to convert formats just to print them.

A brief video describing SPIRAL is embedded just below, with a closer look at how the pieces fit together.

[Tommy] has a great write-up about designing and building a minimalistic handheld electronic game called
“Higher Lower”. It’s an audio-driven game in which the unit plays two tones and asks the player to choose whether the second tone was higher in pitch, or lower. The game relies on 3D printed components and minimal electronics, limiting player input to two buttons and output to whatever a speaker stuck to an output pin from an ATtiny85 can generate.

Gameplay may be straightforward, but working with so little raises a number of design challenges. How does one best communicate game state (and things like scoring) with audio tones only? What’s the optimal way to generate a random seed when the best source of meaningful, zero-extra-components entropy (timing of player input) happens after the game has already started? What’s the most efficient way to turn a clear glue stick into a bunch of identical little light pipes? [Tommy] goes into great detail for each of these, and more.

In addition to the hardware and enclosure design, [Tommy] has tried new things on the software end of things. He found that using tools intended to develop for the Arduboy DIY handheld console along with a hardware emulator made for a very tight feedback loop during development. Being able to work on the software side without actually needing the hardware and chip programmer at hand was also flexible and convenient.

We’ve seen [Tommy]’s work before about his synth kits, and as usual his observations and shared insights about bringing an idea from concept to kit-worthy product are absolutely worth a read.

You can find all the design files on the GitHub repository, but Higher Lower is also available as a reasonably-priced kit with great documentation suitable for anyone with an interest. Watch it in action in the video below.

Adding textures is a great way to experiment with giving 3D prints a different look, and [PandaN] shows off a method of adding a wood grain effect in a way that’s easy to play around with. It involves using a 3D model of a log (complete with concentric tree rings) as a print modifier. The good news is that [PandaN] has already done the work of creating one, as well as showing how to use it.

In the slicer software one simply uses the log as a modifier for an object to be printed. When a 3D model is used as a modifier in this way, it means different print settings get applied everywhere the object to be printed and the modifier intersect one another.

In the case of this project, the modifier shifts the angle of the fill pattern wherever the models intersect. A fuzzy skin modifier is used as well, and the result is enough to give a wood grain appearance to the printed object. When printed with a wood filament (which is PLA mixed with wood particles), the result looks especially good.

We’ve seen a few different ways to add textures to 3D prints, including using Blender to modify model surfaces. Textures can enhance the look of a model, and are also a good way to hide layer lines.

In addition to the 3D models, [PandaN] provides a ready-to-go project for Bambu slicer with all the necessary settings already configured, so experimenting can be as simple as swapping the object to be printed with a new 3D model. Want to see that in action? Here’s a separate video demonstrating exactly that step-by-step, embedded below.

[It’s on my MIND] designed a clever BB blaster featuring a four-bar linkage that prints in a single piece and requires no additional hardware. The interesting part is how it turns a trigger pull into launching a 6 mm plastic BB. There is a spring, but it only acts as a trigger return and plays no part in launching the projectile. So how does it work?

The usual way something like this functions is with the trigger pulling back a striker of some kind, and putting it under tension in the process (usually with the help of a spring) then releasing it. As the striker flies forward, it smacks into a BB and launches it. We’ve seen print-in-place shooters that work this way, but that is not what is happening here.

With [It’s on my MIND]’s BB launcher, the trigger is a four-bar linkage that transforms a rearward pull of the trigger into a forward push of the striker against a BB that is gravity fed from a hopper. The tension comes from the BB’s forward motion being arrested by a physical detente as the striker pushes from behind. Once that tension passes a threshold, the BB pops past the detente and goes flying. Thanks to the mechanical advantage of the four-bar linkage, the trigger finger doesn’t need to do much work. The spring? It’s just there to reset the trigger by pushing it forward again after firing.

It’s a clever design that doesn’t require any additional hardware, and even prints in a single piece. Watch it in action in the video, embedded just below.

Want to turn a scaled vector graphic into a multicolor 3D print, like a sign? You’ll want to check out [erkannt]’s svg2solid, a web-based tool that reads an SVG and breaks the shapes up by color into individual STL files. Drag those into your slicer (treating them as a single object with multiple parts) and you’re off to the races.

This is especially handy for making 3D printed versions of things like signs, and shown here is an example of exactly that.

It’s true that most 3D printer software supports the .svg format natively nowadays, but that doesn’t mean a tool like this is obsolete. SVG is a 2D format with no depth information, so upon import the slicer assigns a arbitrary height to all imported elements and the user must make any desired adjustments manually. For example, a handy tip for making signs is to make the “background” as thick as desired but limit colored elements to just a few layers deep. Doing so minimizes filament switching while having no impact on final visual appearance.

Being able to drag SVGs directly into the slicer is very handy, but working with 3D models has a certain “what you see is what you get” element to it that can make experimentation or alternate applications a little easier. Since svg2solid turns an SVG into discrete 3D models (separated by color) and each with user-defined heights, if you find yourself needing that then this straightforward tool is worth having in your bookmarks. Or just go straight to the GitHub repository and grab your own copy.

On the other hand, if you prefer your 3D-printed signs to be lit up in a faux-neon style then here’s how to do that in no time at all. Maybe there’s a way to mix the two approaches? If you do, be sure to use our tips line to let us know!

Within the nuclear sciences, including fuel production and nuclear medicine (radiopharmaceuticals), often specific isotopes have to be produced as efficiently as possible, or allow for the formation of (gaseous) fission products and improved cooling without compromising the fuel. Here having the target material possess an optimized 3D shape to increase surface area and safely expel gases during nuclear fission can be hugely beneficial, but producing these shapes in an efficient way is complicated. Here using photopolymer-based stereolithography (SLA) as  recently demonstrated by [Alice Zanini] et al. with a research article in Advanced Functional Materials provides an interesting new method to accomplish these goals.

In what is essentially the same as what a hobbyist resin-based SLA printer does, the photopolymer here is composed of uranyl ions as the photoactive component along with carbon precursors, creating solid uranium dicarbide (UC₂) structures upon exposure to UV light with subsequent sintering. Uranium-carbide is one of the alternatives being considered for today’s uranium ceramic fuels in fission reactors, with this method possibly providing a reasonable manufacturing method.

Uranium carbide is also used as one of the target materials in ISOL (isotope separation on-line) facilities like CERN’s ISOLDE, where having precise control over the molecular structure of the target could optimize isotope production. Ideally equivalent photocatalysts to uranyl can be found to create other optimized targets made of other isotopes as well, but as a demonstration of how SLA (DLP or otherwise) stands to transform the nuclear sciences and industries.

In the driving simulator community, setups can quickly grow ever more complicated and expensive, all in the quest for fidelity. For [CNCDan], rather than buy pedals off the shelf, he opted to build his own.

[Dan] has been using some commercial pedals alongside his own DIY steering wheel and the experience is rather lackluster in comparison. The build starts with some custom brackets. To save on cost, they are flat with tabs to let you know where to bend it in a vise. Additionally, rather than three sets of unique brackets, [Dan] made them all the same to save on cost. The clutch and throttle are a simple hall effect sensor with a spring to provide feedback. However, each bracket provides a set of spring mounting holes to adjust the curve. Change up the angle of the spring and you have a different curve. The brake pedal is different as rather than measure position, it measures force. A load cell is perfect for this. The HX711 load cell sensor board that [Dan] bought was only polling at 10hz. Lifting a pin from ground and bodging it to VDD puts the chip in 80hz, which is much more usable for a driving sim setup.

[Dan] also cleverly uses a 3d printed bushing without any walls as resistance for the pedal. Since the bushing is just the infill, the bushing stiffness is controlled by the infill percentage. Aluminum extrusion forms the base so [Dan] can adjust the exact pedal positions. To finish it off, a bog standard Arduino communicates to the PC as a game controller.

The project is on GitHub. Perhaps the next version will have active feedback, like this DIY pedal setup.

One of the most basic problems with robotic arms and similar systems is keeping the weight down, as more weight requires a more rigid frame and stronger actuators. Cable-driven systems are a classic solution, and a team of researchers from MIT and Zhejiang University recently shared some techniques for designing fully 3D printed cable-driven mechanisms.

The researchers developed a set of four primitive motion components: a bending component, a coil, screw-like, and a compressive component. These components can work together in series or parallel to make much more complicated structures. To demonstrate, the researchers designed a gripping tentacle, a bird’s claw, and a lizard-like walking robot, but much more complicated structures are certainly possible. Additionally, since the cable itself is printed, it can have extra features, such as a one-way ratcheting mechanism or bumps for haptic feedback.

These printed cables are the most novel aspect of the project, and required significant fine-tuning to work properly. To have an advantage over manually-assembled cable-driven systems, they needed to be print-in-place. This required special printer settings to avoid delamination between layers of the cable, cables sticking to other components, or cables getting stuck in the mechanism’s joints. After some experiments, the researchers found that nylon filament gives the best balance between cable strength and flexibility, while not adhering tightly to the PLA structure.

We’ve seen cable-driven systems here a few times before. If you’re interested in a deeper dive, we’ve covered that too.

Thanks to [Madeinoz67] for the tip!

You know how it is. You’re all cozy in bed but not quite ready to doze off. You’re reading Hackaday (Hackaday is your go-to bedtime reading material, right?) or you’re binge-watching your latest reality TV obsession on your tablet. You feel the tablet growing heavier and heavier as your arms fatigue from holding it inches above your face. You consider the embarrassment you’ll endure from explaining how you injured your nose as the danger of dropping the tablet gradually increases. The struggle is real.

[Will Dana] has been engineering his way out of this predicament for a few years now, and with the recent upgrade to his iPad suspension system he is maximizing his laziness, but not without putting in a fair amount of hard work first.

The first iteration of the device worked on a manual pulley system whereby an iPad was suspended from the ceiling over his bed on three cords. Pulling on a cord beside the bed would raise the bracket used for holding the iPad out of the way while not in use. This new iteration takes that pesky cord pulling out of the user’s hands, replacing it with a motorized winch. A spot of dark ink on one of the cords in combination with a light sensor helps to calibrate the system so that the ESP32 which controls it always knows the proper limits of operation.

Of course, if, like [Will], you’re using an ESP32, and your room is already fully controlled by a voice interface, you may as well integrate the two. After all, there is no sense in wasting precious energy by pressing buttons. Utter a simple command to Alexa once you’re tucked in, and it’s time for hands-free entertainment.

We’ve covered several of [Will]’s previous creations, such as his Motorized Relay Computer and Harry Potter-inspired Sorting Hat.

A recent project over on Hackaday.io from [Michael Gardi] is Trekulator – Where No Maker Has Gone Before.

This is a fun build and [Michael] has done a very good job of emulating the original device. [Michael] used the Hackaday.io logging feature to log his progress. Starting in September 2024 he modeled the case, got his original hardware working, got the 7-segment display working, added support for sound, got the keypad working and mounted it, added the TFT display and mounted it, wired up the breadboard implementation, designed and implemented the PCBs, added some finishing touches, installed improved keys, and added a power socket back in March.

It is perhaps funny that where the original device used four red LEDs, [Michael] has used an entire TFT display. This would have been pure decadence by the standards of 1977. The software for the ESP32 microcontroller was fairly involved. It had to support audio, graphics, animations, keyboard input, the 7-segment display, and the actual calculations.

The calculations are done using double-precision floating-point values and eight positions on the display so this code will do weird things in some edge cases. For instance if you ask it to sum two eight digit numbers as 90,000,000 and 80,000,000, which would ordinarily sum to the nine digit value 170,000,000, the display will show you a different value instead, such as maybe 17,000,000 or 70,000,000. Why don’t you put one together and let us know what it actually does! Also, can you find any floating-point precision bugs?

This was a really fun project, thanks to [Michael] for writing it up and letting us know via the tips line!