Hot Wire Foam Cutter Does Circles, Too

Foam is all kinds of useful, but trying to cut it with scissors or a serrated plastic knife is usually an exercise in futility. What you really need is a hot wire for nice clean cuts. [Elite Worm] built a hot wire foam cutter that can cut any type of foam with ease, be it Styrofoam or grey craft foam.

There are a ton of ways to heat up a taut piece of nichrome wire, but few of them are as good looking as this one. [Elite Worm] designed and printed a table with an adjustable fence so it can be used like a table saw. There is also a circle-cutting jig that looks really handy.

This design uses a 12 V power regulator to heat up a piece of tension-adjustable nichrome wire for buttery smooth cuts. This thing looks fantastic all the way down to the cable management scheme. All the files are available on Thingiverse if you want to build one for yourself, but you’ll need to use something other than PLA.

This wire cutter is pretty versatile, but you could go even smaller with a handheld version, or build a larger, CNC-based machine.

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Scratch Building A Supersized CNC Router

Many of us have spent the better part of a year on COVID-19 lockdown, and what do we have to show for it? Bit of progress on the Netflix queue? Maybe a (slightly) cleaned up garage or workshop? Not if you’re [Bob] of Making Stuff fame: he’s spent the last nine months working on a completely custom CNC router big enough to take a whole sheet of plywood.

The build is documented over a series of nearly a dozen YouTube videos, the first of which was put out all the way back in January of 2020. Seeing [Bob] heading to the steel mill to get his frame components with nary a mask in sight is a reminder of just how long he’s been working on this project. He’s also put together a comprehensive Bill of Materials on his website should anyone want to follow in his footsteps. Coming in at only slightly less than $4,000 USD, it’s certainly not a budget build. But then when we’re talking about a machine of this scale, nothing comes cheap.

Every component on this build is heavy-duty.

Even if you don’t build you own version of this router, it’s impossible to watch the build log and not get inspired about the possibilities of such a machine. In the last video we’re even treated to a bit of self-replicating action, as the jumbo CNC cuts out the pieces for its own electronics enclosure.

You can tell from the videos that [Bob] is (rightfully) proud of his creation, and isn’t shy about showing the viewer each and every triumph along the way. Even when things don’t go according to plan, there are lessons to be learned as he explains the problems and how they were ultimately resolved.

Of course, we know a home-built CNC router doesn’t need to cost thousands of dollars or take up as much space as a pool table. The average Hackaday reader probably has no need of a monster like this, and wouldn’t have anywhere to keep it even if they did. But that doesn’t mean we can’t look on with envy as we wait to see what kind of projects [Bob] churns out with such an incredible tool in his arsenal.

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HackRF PortaPack Firmware Spoofs All The Things

The HackRF is an exceptionally capable software defined radio (SDR) transceiver, but naturally you need to connect it to a computer to actually do anything with it. So the PortaPack was developed to turn it into a stand-alone device with the addition of a touchscreen LCD, a few buttons, and a headphone jack. With all the hardware in place, it’s just a matter of installing a firmware capable enough to do some proper RF hacking on the go.

Enter MAYHEM, an evolved fork of the original PortaPack firmware that the developers claim is the most up-to-date and feature packed version available. Without ever plugging into a computer, this firmware allows you to receive, decode, and re-transmit a dizzying number of wireless protocols. From firing off the seating pagers at a local restaurant to creating a fleet of phantom aircraft with spoofed ADS-B transponders, MAYHEM certainly seems like it lives up to the name.

[A. Petazzoni] recently put together a detailed blog post about installing and using MAYHEM on the HackRF/PortaPack, complete with a number of real-world examples that show off just a handful of possible applications for the project. Jamming cell phones, sending fake pager messages, and cloning RF remotes is just scratching the surface of what’s possible.

It’s not hard to see why some have already expressed concern about the project, but in reality, none of these capabilities are actually new. This firmware simply brings them all together in one easy-to-use package, and while there might be an argument to be made about proliferation, we all know that the responsibility to behave ethically rests on the user and not the tools.

Building A Workshop Crane From Scratch

Buying tools is all well and good, but it doesn’t suit the ethos of Youtube channel [Workshop From Scratch]. Building what you need is much more the go, and that’s demonstrated ably with this home-built electric workshop crane.

The crane is put together in a straightforward manner using basic steelworking techniques. Plates and bars are machined with a drill press, bandsaw and grinder, though we could imagine you could use hand tools if you were so inclined. An ATV winch is pressed into service to do the heavy lifting, powered by a set of 12V lead acid batteries placed in the base. This design choice does double duty as both a mobile power supply for the crane, and acts as a counterweight in the base.

The final result looks sharp in its orange paint finish, and does a good job of moving heavy equipment around the workshop. The legs are reconfigurable, so that even very heavy loads can be lifted with appropriate counterweight placed on the back. It’s a significant upgrade on the earlier version we featured last year, which was hydraulic in operation. Video after the break.

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Blue Pill As A Nerdy Swiss Army Knife

Not everyone can afford an oscilloscope, and some of us can’t find a USB logic analyzer half the time. But we can usually get our hands on a microcontroller kit, which can be turned into a makeshift instrument if given the appropriate code. A perfect example is buck50 developed by [Mark Rubin], an open source firmware to turn a STM32 “Blue Pill” into a multi-purpose test and measurement instrument.

buck50 comes with a plethora of functionality built in which includes an oscilloscope, logic analyzer, and bus monitor. The device is a two way street and also comes with GPIO control as well as PWM output. There’s really a remarkable amount of functionality crammed into the project. [Mark] provides a Python application that exposes a text based UI for configuring and using the device though commands and lots of commands which makes this really nerdy. There are a number of options to visualize the data captured which includes gnuplot, gtk wave and PulseView to name a few.

[Mark] does a fantastic job not only with the firmware but also with the documentation, and we really think this makes the project stand out. Commands are well documented and everything is available on [GitHub] for your hacking pleasure. And if you are about to order a Blue Pill online, you might want to check out the nitty-gritty of the clones that are floating around.

Thanks [JohnU] for the tip!

A Motorized Rotary Shop Table From Scratch

As we’ve seen over the years, it’s possible to bootstrap your own metalworking shop using little more than a pile of scrap steel, a welder, and an angle grinder. With time and dedication, you can build increasingly complex shop tools until you’ve got yourself a nice little post-apocalyptic workshop. It’s the whole idea behind the [Workshop From Scratch] channel, and we never get bored of seeing his incredible backyard engineering.

But eventually, you’ll have built all the basic stuff. What then? Well, as [Workshop From Scratch] shows in a recent video, you can start working on the luxuries. Do you need a motorized table that will let you spin the workpiece and position it an at arbitrary angle? No, probably not. But as the video after the break shows, it’s certainly a handy thing to have around the shop. We especially like how he uses it to quickly and easily produce nearly perfect circular welds.

Note the welded standoffs used to hold on the lid.

From a technical standpoint, this is perhaps one of his more straightforward builds. But at the same time, the attention to detail that he puts into even this “simple” design is phenomenal. Nothing is wasted, and cutoff pieces from one section are often used in imaginative ways elsewhere.

[Workshop From Scratch] is truly a master of working with what you have, and this project is a perfect example. We especially like the tilt mechanism, which uses a massive leadscrew spun by a wiper motor salvaged from an Audi A8 B4. It looks like a fair amount of new hardware went into the control electronics, but even still, we have no doubt that the cost of this build is well below the purchase price of a commercial alternative.

Much like his hydraulic lifting table or motorized plasma cutter, not everyone is going to need something this elaborate in their home shop. But his magnetic vise and mobile drill press cart are far more approachable for the home gamer. Of course even if you don’t follow along and build your own versions of his tools, it’s always worth tuning in just to see him work.

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Desktop Wind Tunnel Brings Aerospace Engineering To The Home Gamer

Computer simulation is indispensable in validating design and used in every aspect of engineering from finite element analysis to traffic simulation to fluid dynamics. Simulations do an amazing job and at a fraction of the time and expense of building and testing a scale model. But those visceral ah-ha moments, and some real-world gremlins, can be easier to uncover by the real thing. Now you don’t need a university research or megacorp lab to run aerodynamic study IRL, you can just build a functional desktop wind tunnel for a pittance.

[Mark Waller] shows off this tidy little design that takes up only about two feet of desk space, and includes the core features that make a wind tunnel useful. Air is pulled through the tunnel using a fan mounted at the exhaust side of the tunnel. The intake is the horn-like scoop, and he’s stacked up a matrix of drinking straws there to help ensure laminar flow of the air as it enters the tunnel. (The straw trick is frequently used with laminar flow water fountains). It also passes through a matrix of tubes about the diameter of a finger at the exhaust to prevent the spin of the fan from introducing a vortex into the flow.

For analysis, five tubes pipe in smoke from an vape pen, driven into the chamber by an aquarium pump. There’s a strip of LEDs along the roof of the tunnel, with a baffle to prevent the light shining on the black rear wall of the chamber for the best possible contrast. The slow-motion video after the break shows the effectiveness of the setup.

Whether you’re a Hackaday Editor cutting their own glider wing profiles using foam and hot wire, or just want to wrap your head around how different profiles perform, this will get you there. And it’ll do it at a fraction of the size that we’ve seen in previous wind tunnel builds.

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