RC Car Becomes Useful Little Mower

When we think of lawn mowers, our first thought is of heavy, rusty old machines that take the best part of an afternoon to get started. Of course, there’s always another way, as [Mark] ably demonstrates with his own build. 

Beginning from an unconventional starting point, [Mark] chose a remote control car, of the type that can flip and drive in both orientations. Having lost the controller, he started by ripping out the original electronics. In its place, an ESP32 receives signals from a FlySky RC receiver, and runs the drive motors with a Sparkfun Monster Motor Shield. Another channel on the receiver is hooked up directly to a drone speed controller driving a brushless motor, outfitted with a sawblade to cut the grass.

It’s a small platform, and one that ordinarily you might doubt could do the job. However, for [Mark]’s purposes, the rig works just fine, and has been doing good work for the last two years! We’ve seen mowers hacked before too, like this autonomous rig out in the wild. Video after break.

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Bantam Tools PCB Mill Gets A Ferocious New Sequel

When the first Bantam Tools’ Milling Machine landed, it put PCB prototyping at the forefront with a smooth software and hardware pipeline for spinning out circuit boards in a manner of minutes. Now the folks at Bantam Tools are back, putting those insights into a new machine that makes cutting aluminum a first class feature. While machine details are still sparse from their announcement page, knowing that Bantam Tools has spent a few years turning classrooms of students into hardware prototypes reassures us that we’re in good hands. Now let’s spill some beans on this beast. Continue reading “Bantam Tools PCB Mill Gets A Ferocious New Sequel”

Marian Croak Is The MVP Of VoIP Adoption

If you’ve ever used FaceTime, Skype, own a Magic Jack, or have donated money after a disaster by sending a text message, then you have Marian Croak to thank. Her leadership and forward thinking changed how Ma Bell used its reach and made all of these things possible.

Marian Croak is a soft-spoken woman and a self-described non-talker, but her actions spoke loudly in support of Internet Protocol (IP) as the future of communication. Humans are always looking for the next best communication medium, the fastest path to understanding each other clearly. We are still making phone calls today, but voice has been joined by text and video as the next best thing to being there. All of it is riding on a versatile network strongly rooted in Marian’s work.

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Magnetic Couplings Make This Lego Submarine Watertight

Although you’d be hard-pressed to tell in some areas, it’s summer in the northern hemisphere, which always seems to bring out the projects that require a swimming pool for adequate testing. The [Brick Experiment Channel]’s latest build, a submersible made almost entirely from Lego, is one such project and has us pining for weather that makes a dip sensible rather than suicidal.

The sub featured in the video below is a significant improvement over the “Sub in a Jug” approach the [Brick Experiment Channel] favored for version 1. Rather than starting with a vessel specifically designed not to hold water, the hull for this vessel is an IKEA food container, with a stout glass body and a flexible lid with silicone seals. And instead of penetrating the hull for driveshafts and attempting to seal them, this time around he built clever magnetic couplings.

The couplings transmit torque from the motors on the inside to gears and props on the outside. And where the first version used a syringe-pump ballast tank to control the depth, this one uses vertical thrusters. The flexible lid proved to be a problem with that scheme, since it tended to collapse as the depth increased, preventing the sub from surfacing. That was solved with some Lego bracing and adjustment of the lead shot ballast used to keep the sub neutrally buoyant.

This looks like a ton of summer fun, and even if you don’t have Legos galore to work with, it could easily be adapted to other materials. There are a ton of other fun [BEC] Lego builds to check out, some of which we’ve covered, including a Lego drone and a playing card shooter.

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Not Just GPS: New Options For Global Positioning

A few weeks ago, China launched the final satellite in its BeiDou-3 satellite positioning system. Didn’t know that China had its own GPS? How about Europe’s Galileo, Russia’s GLONASS, or Japan’s QZSS? There’s a whole world of GPS-alikes out there. Let’s take a look.

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Designing 3D Printed Enclosures For KiCad PCBs

If you’ve used KiCad before, you’re certainly familiar with the handy 3D view that shows you a rendered view of what your assembled board would look like. But as [Vadim Panov] explains, you can take this capability a step further. With a few extra tools and a little bit of know-how, you can leverage KiCad’s PCB renderings to make custom 3D printable enclosures.

The first step is to design the PCB as you normally would in KiCad. This could be an original PCB of your own invention, or a digital representation of an off-the-shelf model you want to build an enclosure for. If the latter, then the PCB doesn’t need to be 100% accurate; the goal is really just to get the big components into roughly the right areas so you can get the clearances right. Though obviously you’ll want to make sure the board’s outer dimensions and mounting hole locations are recreated as accurately as possible.

From there, [Vadim] recommends a tool called StepUp. This will take your PCB KiCad PCB files and create either a STEP or STL file of the assembled board which can be imported into your CAD package of choice. For the purposes of this demonstration he’s sticking with FreeCAD, as he likes the idea of it being a completely FOSS toolchain from start to finish.

Now that you have a model of the PCB in your CAD software, the rest is up to you. Naturally, there are existing enclosure models you can use such as the ones produced by the “Ultimate Box Maker” that we covered previously, but you could just as easily start building a new enclosure around the digital PCB.

Looking for a bit more guidance? As it so happens, our very own [Anool Mahidharia] will be presenting a class on how you can develop a KiCad + FreeCAD workflow as part of our recently launched HackadayU initiative.

Milling Dies And Injection Moulding Some Acrylic Lenses

[Zach] over at his channel Breaking Taps has put up an extraordinary account on manufacturing some homemade acrylic lenses. In the end, not only does he produce some beautiful concave lenses, he also covers the complete manufacturing process, from milling the aluminium die used for injection moulding to tweaking the parameters associated with injecting the actual acrylic, he even goes over the limitations of optics produced in this fashion.

What caught our eye in particular, was how [Zach] used the finished product to practically demonstrate photoelasticity originating from the stress induced by the moulding process. You might be familiar with describing the optical properties of a material by a single number, i.e its permittivity. But what happens if in addition to altering speed, the material also alters the polarisation and direction of light depending on the stress distribution within the material? Whilst a quantitative answer gets a bit complicated you can check out [Zach’s] additional videos to visualise the answer in a pretty and colourful way, without resorting to fancy computer simulations! If however, you really want to persist with the simulation route, check out our article on stress analysis in a totally different setting using Finite Element Analysis.

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