The $16 PCB Robot

It is a fun project to build a simple robot but, often, the hardest part these days is creating the mechanical base. [Concrete Dog] has a new open source design for stoRPer that uses a PC board as the base. The board has a Raspberry Pi Pico and motor drivers. The modular design allows you to add to it easily and use custom wheels. The video below shows some treaded wheels and some mechanum wheels with gears.

There are mounting holes for sensors and also a way to put another deck above to hold other circuits, power, or whatever you like. There’s lots you could do with this as a starting point.

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Tricky 3D Printed Joinery Problem? Give Heat Staking A Try

When you just can’t 3D print something as a monolithic part, you’re going to have to join pieces together. In such cases, most of us instinctively include threaded inserts or nut slots in the design, or even reach for a tube of CA glue. But perhaps you should be thinking more along the lines of heat-staking your printed parts together.

Although you might not be familiar with the term, if you’ve looked inside anything made out of plastic, chances are good you’ve seen a heat-staked joint. As [Richard Sewell] explains, a heat-staked joint is nothing more than the classic mortise-and-tenon made from plastic where the tenon stands proud of the joint face so it can be softened with heat. The tenon spreads out so the joint can’t be pulled apart. A variant on the theme includes a mortise with a generous chamfer so the melted tenon can spread out, providing not only extra resistance to pull-out be also a more flush surface.

To melt the joint, [Richard] simply uses a soldering iron and a little pressure. To spread out both the heat and the force a bit, he uses the barrel of the iron rather than a tip, although we could see a broad chisel tip being used for smaller joints. Either way, a layer of Kapton tape helps keep the iron from getting gunked up with melted plastic. [Richard] lists a host of advantages for this kind of plastic joinery, including eliminating the need for additional hardware. But we think the best feature of this joint is that by avoiding monolithic prints, each aspect of a part can have its layer lines optimized.

While it probably isn’t applicable everywhere, heat-staking looks like a technique to keep in mind. We’d love to see [Stefan] over at CNC Kitchen do some of his testing magic on these joints, like he did for threaded inserts.

Reducing Poop On Multicolor Prints

While multicolor printing eliminates painting steps and produces vibrant objects, there are two significant downsides; filament consumption and print time. A single-nozzle filament printer needs to switch from one color to another, and doing so involves switching to the other filament and then purging the transition filament that contains a mixture of both colors, before resuming the print with the clean new color.

[teachingtech] tests out a variety of methods for reducing print time and waste. One surprising result was that purging into the infill didn’t result in significant savings, even when the infill was as high as 50%. Things that did have a positive effect included reducing the amount of purge per transition based on light to dark color changes, and printing multiple copies at once so that even though the total amount of waste was the same as a single part, the waste per part was reduced.

All of the tests were with the same model, which had 229 color changes within a small part, so your mileage may vary, but it’s an interesting investigation into some of the deeper settings within the slicer. Reducing filament waste and print time is an admirable goal, and if you make your own extruder, you can turn all of that purge waste into various shades of greenish brownish filament. Continue reading “Reducing Poop On Multicolor Prints”

Mobile phone reading an NFC tag with information on a garden plant

NFC Puts A Stake In The Ground

Sometimes we have a new part or piece of tech that we want to use, and it feels like a solution looking for a problem. Upon first encountering NFC Tags, [nalanj] was looking for an application and thought they might make a great update to old-fashioned plant markers in a garden. Those are usually small and, being outside 24/7, the elements tend to wear away at what little information they hold.

traditional plant marker

[nalanj] used a freeform data structuring service called Cardinal to set up text information fields for each plant and even photos. Once a template has been created, every entry gets a unique URL that’s perfect for writing to an NFC tag. See the blog post on Cardinal’s site for the whole process, the thought behind the physical design of the NFC tag holder, and a great application of a pause in the 3D print to encapsulate the tags.

NFC tags are super hackable, though, so you don’t have to limit yourself to lookups in a plant database. Heck, you could throw away your door keys.

A small black microphone in a black 3d printed mount. The mount is attached to an adjustable silver neck attached to a desk clamp from an IKEA lamp.

IKEA Hack – Kvart Into Mic Stand

While audiophiles might spend gazillions of hours finely honing a microphone stand that isolates their equipment from the trials and perturbations of the world, most of us who use a microphone don’t need anything so elaborate. Hackaday contributing editor [Jenny List] hacked together some thrift store finds into a snazzy adjustable mic setup as you can see in the video below the break.

Using the flexible neck and clamp of an IKEA Kvart as a base, [Lists]’s mic stand looks like a simple, but exceedingly useful tool. She first removed the lamp, shade, and cord before designing a 3D-printed mount to attach to the lamp’s neck. Since the bolted lamp end of the connection goes straight to an action camera mounting system, we can see this being handy for mounting any number of other things besides microphones. Another 3D-printed mount attaches the Logitech gaming microphone to the action camera connector, and the whole thing can either be bolted together or use a printed pin. All the parts can be found in a GitHub repository.

Looking for more microphone hacks? Check out this DIY ribbon microphone or the Ambi-Alice ambisonic mic.

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Wood game piece being carved by a CNC mill with a hacked rotary axis

This $12 CNC Rotary Axis Will Make Your Head Spin

[legolor] brings us a great, cheap rotary axis to add to your small 3 axis CNC mills. How are you going to generate G-Code for this 4th axis? That’s the great part, and the hack, that [legolor] really just swapped the Y axis for the rotation. To finish the workflow and keep things cheap accessible to all there’s a great trick to “unwrap” your 3D model so your CAM software of choice thinks it’s still using a linear Y axis and keeps your existing workflow largely intact. While this requires an extra step in Blender to do the unwrapping, we love the way this hack changes as little of the rest of your process as possible. The Blender script might be useful for many other purposes too.

Wood game pieces carved from wood by a CNC mill with a hacked rotary axis

The results speak for themselves too! We thought the 3D printed parts were suspect in a CNC setup, but for the small scale of game pieces and milling wood, the setup is stable enough to produce a surprisingly accurate and detailed finish. If you want to try the same approach with something larger or a tougher material, [legolor] has a suggestion of a tailstock setup that’s still under $100 USD. Continue reading “This $12 CNC Rotary Axis Will Make Your Head Spin”

Alternatives To Pins And Holes For 3D Printed Assemblies

When we have two 3D printed parts that need to fit together, many of us rely on pins and holes to locate them and fix them together. [Slant 3D] has explored some alternative ideas in this area that may open up new avenues for your own designs.

Their first idea was to simply chamfer the pins and holes. This allows the object to be printed in a different orientations without compromising the fit. It also makes the features less brittle and creates a broader surface for gluing. Another alternative is using fins and slots, which again add robustness compared to flimsy pins. By chamfering the edges of the fins, they can be printed vertically for good strength and easy location without the need for support material.

Neither option requires much extra fuss compared to typical pin-and-hole designs. Plus, both are far less likely to snap off and ruin your day. Be honest, we’ve all been there. Meanwhile, consider adding folded techniques to your repertoire, too.

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