Misc Hacks

4137 Articles

Mapping Tool Helps Identify Usable Land For Building

July 5, 2025 by 9 Comments

How would you go about identifying usable land that suits your building tastes? [Scott Sexton] was specifically looking for land that’s not too steep to build on, and realized that existing resources didn’t easily offer him this information. He thus dived into the world of GIS to try and solve this issue for himself.

[Scott] hoped that USGS maps might provide the information he needed, but found they lacked grade information, only presenting elevation and topographic data instead. From past experience reading such maps, he knew that seeing a lot of topographical lines close together tended to indicate steeper areas, but wasn’t sure on how to actually get the computer to parse this and spit out the information on steepness and grade that he wanted.

Ultimately, he set about downloading USGS elevation data in three-meter resolution. He then applied some calculus to determine the rate of change of the slope across areas of the data in order to mathematically find what he was looking for. Namely, flatter areas that would be more suitable for future construction. He then took the work even further, tweaking the output of his tools and automating until he could quickly and readily generate usability maps of areas of interest. He was even able to sanity-check his work by verifying that it correctly identified roads as obviously flat areas.

If you’ve ever tinkered with GIS work, [Scott’s] usability project may be of some interest. We’ve also seen amusing examples of what can go wrong when digital mapping data is used without sanity checks. Meanwhile, if you’ve got your own GIS hacks on the go, don’t hesitate to notify us via the tipsline!

Smart Mjolnir Makes Questionable Judgement Call On Your Worthiness

July 3, 2025 by 3 Comments

Mjolnir, also known as Thor’s hammer, is a discerning thing, at least if you believe the modern Marvel canon. [alemanjir] decided to build a semi-functional replica that makes judgement calls of its own, though they’re perhaps a little less thought-out than the storied hammer of legend.

The build consists of a 3D-printed hammer prop, inside of which is a Raspberry Pi Pico microcontroller running the show. It’s hooked up to a MPR121 touch sensor that detects when someone grips the handle of the hammer. At this point, the Pico makes a pseudorandom “worthiness check” as to whether the holder is righteous enough to wield the hammer. If they are pure of heart, it unlocks a magnet which frees the hammer from whatever metallic surface it might be stuck to. [alemanjir] also included a little additional functionality, with the hammer playing various sounds when swung thanks to a speaker and a ADXL345 accelerometer secreted inside.

One wonders whether the electromagnet inside is strong enough to hold out against an unworthy person lifting it from the ground. While it’s perhaps not as powerful or as decisive as the mythical object, it’s nonetheless a fun learning project that likely taught [alemanja] some useful basics of embedded development.

We’ve featured some terrifying takes of the Mjolnir prop before, too, like this shockingly high voltage version. Video after the break.

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Challenge: Square A Voltage

July 1, 2025 by 17 Comments

Your design task, should you decide to accept it: given an input voltage, square it. Ok, that’s too hard since squaring 8 volts would give you 64 volts, so let’s say the output should be 10% of the square, so 8 volts in would result in 6.4V. How do you do it? [Engineering Prof.] knows how and will show you what you can do in the video below.

The circuit uses two op amps and some transistors. However, the transistors are used in a way that depends on the temperature, so it is important to use a transistor array so they are matched and will all be at the same temperature.

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There Are Better Lego-Compatible Universal Joints Out There

July 1, 2025 by 11 Comments

Lego’s Technic line features all kinds of mechanical devices, from cogs to gears to chains and even pneumatic components. However, the vast majority of these components are made out of plastic and are only capable of toy-like levels of performance. In the competitive world of Lego YouTube, builders often push these parts to their limits, breaking them more often than you might think. To that end, [Brick Experiment Channel] has been investigating stouter Lego-compatible universal joints from a variety of third-party manufacturers.

The video starts with a simple demonstration, showing that a Lego universal joint pops apart at just 0.4 Nm of torque. It’s no surprise, given it relies on tiny plastic pins in snap-fit joints. However, this means that it’s not that hard to build a stronger universal joint to outperform the stock parts.

The video steps through a range of other options available on the market. For example, CaDA builds a universal joint using aluminium sleeves, a copper center, and steel pins to join everything together. It’s so strong that the plastic Lego axles fail long before the joint does. Tested with third-party aluminum axles, it eventually fails at 2.3 Nm of torque when the aluminum sleeve snaps. An all-steel joint from MTP goes even harder, eventually stripping out its axle mount at 4 Nm. The rest of the video goes on to explore angular performance, size, and other design features.

It’s fair to say that if you’re swapping out universal joints and axles for aluminum steel parts, you’re not really playing with Lego anymore. At the same time, it’s neat that there exists a sort of defacto standard kit for mechanical experimentation that is now being expanded upon with stronger components. Video after the break.

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Sand Drawing Table Inspired By Sisyphus

June 30, 2025 by 7 Comments

In Greek mythology, Sisyphus was a figure who was doomed to roll a boulder for eternity as a punishment from the gods. Inspired by this, [Aidan], [Jorge], and [Henry] decided to build a sand-drawing table that endlessly traces out beautiful patterns (or at least, for as long as power is applied). You can watch it go in the video below.

The project was undertaken as part of the trio’s work for the ECE4760 class at Cornell. A Raspberry Pi Pico runs the show, using TMC2209 drivers to command a pair of NEMA17 stepper motors to drag a magnet around beneath the sand. The build is based around a polar coordinate system, with one stepper motor rotating an arm under the table, and another panning the magnet back and forth along its length. This setup is well-suited to the round sand pit on top of the table, made with a laser-cut wooden ring affixed to a thick base plate.

The trio does a great job explaining the hardware and software decisions made, as well as showing off how everything works in great detail. If you desire to build a sand table of your own, you would do well to start here. Or, you could explore some of the many other sand table projects we’ve featured over the years.

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The underside of the scanner is shown. Four power supply units are visible on the lower side, and assorted electronics are visible on the top side. In the middle, two linear tracks adapted from a 3D printer run along the length of the scanner, and several motors can be seen mounted between the rails.

A Scanner For Arduino-Powered Book Archiving

June 29, 2025 by 4 Comments

Scanners for loose papers have become so commonplace that almost every printer includes one, but book scanners have remained frustratingly rare for non-librarians and archivists. [Brad Mattson] had some books to scan, but couldn’t find an affordable scanner that met his needs, so he took the obvious hacker solution and built his own.

The scanning process starts when a conveyor belt removes a book from a stack and drops it onto the scanner’s bed. Prods mounted on a rail beneath the bed straighten the book and move it into position for the overhead camera to take a picture of the cover. Next, an arm with a pneumatic gripper opens the cover, and a metal bar comes down to hold it in place.

The page-turning mechanism uses two fans: one fan blows from the side of the book to ruffle the pages and separate them, while the other is mounted on a swiveling arm. This fan blows away from the page, providing a gentle suction that holds the page to the arm as it turns the page over. Finally, a glass plate descends over the book to hold the pages flat, the camera takes a picture, the glass plate retracts, and the scanner moves on to the next page.

It is hard to imagine, but have a look at the video in the post if you really want to see it in action.

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Standing Desk Uses Pneumatics To Do The Job

June 27, 2025 by 6 Comments

Most standing desks on the market use electric motors or hand cranks to raise and lower the deck. However, [Matthias Wandel] found a Kloud standing desk that used an altogether different set up. He set about figuring out how it worked in the old-fashioned way—by pulling it apart.

The Kloud desk relies on pneumatics rather than electrical actuators to move up and down. Inside the desk sits a small tank that can be pressurized with a hand-cranked mechanism. A lever can then be used to release pressure from this tank into a pair of pneumatic cylinders that drive the top of the desk upwards. The two cylinders are kept moving in sync by a tensioned metal ribbon that ties the two sides together. The mechanism is not unlike a gas lift chair—holding the lever and pushing down lets the desk move back down. Once he’s explained the basic mechanism, [Matthias] gets into the good stuff—pulling apart the leg actuator mechanism to show us what’s going on inside in greater detail.

If you’ve ever thought about building your own standing desk, this might be a video worth watching. We’ve featured some other great pneumatics projects before, too. Video after the break.

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