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Hackaday Links: June 29, 2025

In today’s episode of “AI Is Why We Can’t Have Nice Things,” we feature the Hertz Corporation and its new AI-powered rental car damage scanners. Gone are the days when an overworked human in a snappy windbreaker would give your rental return a once-over with the old Mark Ones to make sure you hadn’t messed the car up too badly. Instead, Hertz is fielding up to 100 of these “MRI scanners for cars.” The “damage discovery tool” uses cameras to capture images of the car and compares them to a model that’s apparently been trained on nothing but showroom cars. Redditors who’ve had the displeasure of being subjected to this thing report being charged egregiously high damage fees for non-existent damage. To add insult to injury, if renters want to appeal those charges, they have to argue with a chatbot first, one that offers no path to speaking with a human. While this is likely to be quite a tidy profit center for Hertz, their customers still have a vote here, and backlash will likely lead the company to adjust the model to be a bit more lenient, if not outright scrapping the system.

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A Wood Chipper From First Principles

For whatever reason, certain pieces of technology can have a difficult time interacting with the physical world. Anyone who has ever used a printer or copier can attest to this, as can anyone whose robot vacuum failed to detect certain types of non-vacuumable waste in their path, making a simple problem much worse. Farm equipment often falls into this category as well, where often complex machinery needs an inordinate amount of maintenance and repair just to operate normally. Wood chippers specifically seem to always get jammed or not work at all, so [Homemade Inventions] took a shot at building one on their own.

To build this screw-based wood chipper, the first thing to fabricate is the screw mechanism itself. A number of circles of thick steel were cut out and then shaped into pieces resembling large lock washers. These were then installed on a shaft and welded end-to-end, creating the helical screw mechanism. With the “threads” of the screw sharpened it is placed into a cylinder with a port cut out to feed the wood into. Powering the screw is a 3 kW electric motor paired with a custom 7:1 gearbox, spinning the screw at around 200 rpm. With that, [Homemade Inventions] has been able to easily chip branches up to 5 centimeters thick, and theorizes that it could chip branches even thicker than that.

Of course, wood chippers are among the more dangerous tools that are easily available to anyone with enough money to buy one or enough skill to build one, along with chainsaws, angle grinders, and table saws, so make sure to take appropriate safety precautions when using or building any of these things. Of course, knowing the dangers of these tools have led to people attempting to make safer versions like this self-propelled chainsaw mill or the semi-controversial table saw safety standard.

Thanks to [Keith] for the tip!

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Building A Tiny Table Saw

If you want a regular table saw, you’re probably best off just buying one—it’s hard to beat the economies of scale that benefit the major manufacturers. If you want a teeny one, though, you might like to build it yourself. [Maciej Nowak] has done just that.

The concept is simple enough; a small motor and a small blade make a small table saw. [Maciej] sourced a remarkably powerful 800-watt brushless motor for the build. From there, the project involved fabricating a suitable blade mount, belt drive, and frame for the tool. Some time was well-spent on the lathe producing the requisite components out of steel and aluminum, as well as a stout housing out of plywood. The motor was then fitted with a speed controller, with the slight inconvenience that it’s a hobby unit designed to run off DC batteries rather than a wall supply. Ultimately, though, this makes the saw nicely portable. All that was left to do was to fit the metal top plate, guides, and a suitably small 3″ saw blade to complete the build.

We’ve seen mini machine tools like these before, too. They can actually be pretty useful if you find yourself regularly working on tiny little projects. Video after the break.

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Game Boy PCB Assembled With Low-Cost Tools

As computers have gotten smaller and less expensive over the years, so have their components. While many of us got our start in the age of through-hole PCBs, this size reduction has led to more and more projects that need the use of surface-mount components and their unique set of tools. These tools tend to be more elaborate than what would be needed for through-hole construction but [Tobi] has a new project that goes into some details about how to build surface-mount projects without breaking the bank.

The project here is interesting in its own right, too: a display module upgrade for the classic Game Boy based on an RP2350B microprocessor. To get all of the components onto a PCB that actually fits into the original case, though, surface-mount is required. For that [Tobi] is using a small USB-powered hotplate to reflow the solder, a Pinecil, and a healthy amount of flux. The hotplate is good enough for a small PCB like this, and any solder bridges can be quickly cleaned up with some extra flux and a quick pass with a soldering iron.

The build goes into a lot of detail about how a process like this works, so if you’ve been hesitant to start working with surface mount components this might be a good introduction. Not only that, but we also appreciate the restoration of the retro video game handheld complete with some new features that doesn’t disturb the original look of the console. One of the other benefits of using the RP2350 for this build is that it’s a lot simpler than using an FPGA, but there are perks to taking the more complicated route as well.

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Buyer Beware: Cheap Power Strips Hold Hidden Horrors

We’ve got a love-hate relationship with discount tool outlet Harbor Freight: we hate that we love it so much. Apparently, [James Clough] is of much the same opinion, at least now that he’s looked into the quality of their outlet strips and found it somewhat wanting.

The outlet strips in question are Harbor Freight’s four-foot-long, twelve-outlet strips, three of which are visible from where this is being written. [James] has a bunch of them too, but when he noticed an intermittent ground connection while using an outlet tester, he channeled his inner [Big Clive] and tore one of the $20 strips to bits. The problem appears to be poor quality of the contacts within each outlet, which don’t have enough spring pre-load to maintain connection with the ground pin on the plug when it’s wiggled around. Actually, the contacts for the hot and neutral don’t look all that trustworthy either, and the wiring between the outlets is pretty sketchy too. The video below shows the horrors within.

What’s to be done about this state of affairs? That’s up to you, of course. We performed the same test on all our outlets and the ground connections all seemed solid. So maybe [James] just got a bad batch, but he’s still in the market for better-quality strips. That’s going to cost him, though, since similar strips with better outlets are about four times the price of the Harbor Freight units. We did find a similar strip at Home Depot for about twice the price of the HF units, but we can’t vouch for the quality. As always, caveat emptor.

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Magnetic Vise Makes Positioning Your Workpiece Easier

[Chris Borge] was doing some fine tapping operations, and wanted a better way to position his workpieces. This was critical to avoid breaking taps or damaging parts. To this end, he whipped up a switchable magnetic vice to do the job.

The key to the build is that the magnetic field can be switched on and off mechanically. This is achieved by having two sets of six magnets each. When the poles of both sets of magnets are aligned, the magnetic field is effectively “on.” When the poles are moved to oppose each other, they effectively cancel each other out, turning the field “off.” [Chris] achieved this functionality with 12 bar magnets, 12 M12 nuts, and a pair of 3D-printed rings. Rotating the rings between two alignments serves to switch the set up on or off. The actual switching mechanism is handled with a cam and slider setup which allowed [Chris] to build a convenient vice with a nice large working area. He also took special effort to ensure the device wouldn’t pick up large amounts of ferrous swarf that would eventually clog the mechanism.

It’s a neat build, and one you can easily recreate yourself. [Chris] has supplied the files online for your printing pleasure. We’ve featured some other types of magnetic vise before, too. Video after the break.

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Learn New Tools, Or Hone Your Skill With The Old?

Buried in a talk on AI from an artist who is doing cutting-edge video work was the following nugget that entirely sums up the zeitgeist: “The tools are changing so fast that artists can’t keep up with them, let alone master them, before everyone is on to the next.” And while you might think that this concern is only relevant to those who have to stay on the crest of the hype wave, the deeper question resounds with every hacker.

When was the last time you changed PCB layout software or refreshed your operating system? What other tools do you use in your work or your extra-curricular projects, and how long have you been using them? Are you still designing your analog front-ends with LM358s, or have you looked around to see that technology has moved on since the 1970s? “OMG, you’re still using ST32F103s?”

It’s not a simple question, and there are no good answers. Proficiency with a tool, like for instance the audio editor with which I crank out the podcast every week, only comes through practice. And practice simply takes time and effort. When you put your time in on a tool, it really is an investment in that it helps you get better. But what about that newer, better tool out there?

Some of the reluctance to update is certainly sunk-cost fallacy, after all you put so much sweat and tears into the current tool, but there is also a real cost to overcome to learn the new hotness, and that’s no fallacy. If you’re always trying to learn a new way of doing something, you’re never going to get good at doing something, and that’s the lament of our artist friend. Honing your craft requires focus. You won’t know the odd feature set of that next microcontroller as well as you do the old faithful – without sitting down and reading the datasheet and doing a couple finger-stretching projects first.

Striking the optimal balance here is hard. On a per-project basis, staying with your good old tool or swapping to the new hotness is a binary choice, but across your projects, you can do some of each. Maybe it makes sense to budget some of your hacking time into learning new tools? How about ten percent? What do you think?