Kritik sah

River tables are something we’ve heard decried as a passé, but we’re still seeing some interesting variations on the technique. Take this example done with bronze instead of epoxy . Starting with two beautiful slabs of walnut, [Burls Art] decided that instead of cutting them up to make guitars he would turn his attention to a river table to keep them more intact. Given the price of copper and difficulty in casting it, he decided to trim the live edges to make a more narrow “river” to work with for the project. Since molten copper is quite toasty and wood likes to catch on fire, he wisely did a rough finish of the table before making silicone plugs of the voids instead of pouring metal directly. The silicone plugs were then used to make sand casting molds, and a series of casting trials moving from copper to bronze finally yielded usable pieces for the table. In case that all seems too simple, there were then several days of milling and sanding to get the bronze and walnut level and ...

If you’ve ever seen those cheap LED fiber optic wands at the dollar store, you’ve probably just thought of them as a simple novelty. However, as [Ancient] shows us, you can turn them into a surprisingly nifty little display if you’re so inclined. The build starts by removing the fiber optic bundle from the wand. One end is left as a round bundle. At the other end, the strands are then fed into plastic frames to separate them out individually. After plenty of tedious sorting, the fibers are glued in place in a larger rectangular 3D-printed frame, which holds the fibers in place over a matrix of LEDs. The individual LEDs of the matrix light individual fibers, which carry the light to the round end of the bundle. The result is a tiny little round display driven by a much larger one at the other end. [Ancient] had hoped to use the set up for a volumetric display build, but found it too fragile to be fit for purpose. Still, it’s interesting to look at nonetheless, and a good demonstrati...

Fluid simulations are a key tool in fields from aerospace to motorsports and even civil engineering. They can be three-dimensional and complicated and often run on supercomputer clusters bigger than your house. However, you can also do simple two-dimensional fluid simulations on very simple hardware, as [mircemk] demonstrates. This build is almost like a simple toy that displays particles rolling around and tumbling as you turn it one way or the other. Behind the scenes, an ESP32 is running the show, simulating a group of particles responding to gravity in a fluid-like manner. The microcontroller is  hooked up with an 3-axis gyroscope and accelerometer, which it uses to track motion and influence the motion of the particles in turn. The results of the simple fluid simulation are displayed on a screen made up of a 16 x 16 matrix of WS2812B addressable RGB LEDs, which add enough color to make the build suitably mesmerizing. There’s something compelling about turning the display an...

The original locking wheel. Shopping carts are surprisingly expensive. Prices range up to about $300 for a cart, which may seem like a lot, but they have to be pretty rugged and are made to work for decades. Plastic carts are cheaper, but not by much. A basic metal cart can be had for about $100 to $150, although shipping might drive that up, too. And carts have a way of vanishing. We’ve seen estimates that cart theft costs hundreds of millions of dollars worldwide annually. To stem the tide, stores sometimes pay a reward to people to round up carts off the street and return them to the store — it’s cheaper than buying a new one. That led [Elmer Isaacks] to patent a solution to this problem in 1968. The [Isaacks] system used lots of magnets. A cart leaving the store had a brake that would be armed by running over a magnet. Customers were expected to follow a path surrounded by magnets to prevent the brake from engaging. If you left the track, a rod passing through the wheel ...

Big-name tube amplifiers often don’t come cheap. Being the preserve of dedicated audiophiles, those delicate hi-fis put their glass components on show to tell you just how pricy they really ought to be. If you just want to dip your toe in the tube world, though, there’s a cheaper and more accessible way to get started. [Jenny List] shows us the way with her neat headphone amp build. The build starts with an off-the-shelf preamp kit based around two common 6J1 tubes. These Chinese pentode valves come cheap and you can usually get yours hands on this kit for $10 or so. You can use the kit as-is if you just want a pre-amp, but it’s not suitable for headphone use out of the box due to its high-impedance output. That’s where [Jenny] steps in. You can turn these kits into a pleasing headphone amp with the addition of a few choice components. As per the schematic on Github , a cheap transformer and a handful of passives will get it in the “good enough” range to work. The transformer isn’t ...

Prints separating from the build plate or warping when you don’t want them to is a headache for the additive manufacturer. [CNC Kitchen] walks us through a technique to use that warping to our advantage . Based on a paper by researchers at the Morphing Matter Lab at UC Berkeley , [CNC Kitchen] wanted to try making 3D printed objects that could self-assemble when placed in hot water. Similar to a bimetal strip that you find in simple thermostats, the technique takes advantage of the stresses baked into the print and how they can relax when reaching the glass transition temperature of the polymer. By printing joints with PLA and TPU layers, you can guide the deformation in the direction you wish, and further tune the amount of stress in the part by changing the print speed of different sections. [CNC Kitchen] found that Hilbert curve infill slows the printer down sufficiently to create relatively stress-free sections of a print to create flat sections which is an improvement over the ...

Looking to write Rust on the ESP32? You’re in luck, a new challenger has entered the scene, looking to help you write code that lasts – [Scott Mabin] and the team from Espressif have brought us the esp-hal 1.0.0-beta. From a personal project to an Espressif-sponsored one to an effort under Espressif’s wing, [Scott] tells us about the arduous journey of bringing first-class Rust support to ESP32 chips, Xtensa and RISC-V alike. In particular, esp-hal , with the hal part standing for Hardware Abstraction Layer, focuses on providing you with a stable API to access hardware, making sure your code can remain stable for years to come. For now, you get drivers for GPIO, UART, SPI and I2C, as well as a number of auxiliary features like time and SoC reset, more than enough for a large amount of projects we hackers build with a generic MCU in mind. Next stop? WiFi and BLE support, of course, an ESP32 just doesn’t feel the same without these two. Rust is a fun and seriously promising languag...

It is a common problem: I have a USB device on a computer out in the shop, and I want to use it from the comfort of my office. What to do? Well, you could remote desktop into the distant machine. But, honestly, I always find any remote desktop more than ssh clunky and somewhat undesirable. Fortunately, Linux can do virtually anything if you only know how to do it. So, this time, I’ll show you how to transport a USB device over your network. Of course, I have a network that reaches out to the shop. It should be a simple matter to tell my desktop machine that one of its USB devices lives across the network. Well, it wasn’t that simple, but it is doable. The Tools The whole thing involves a program called usbip . That should be the end of it, but of course, it isn’t. In order for this to work, both machines on the network will need some kernel modules and a daemon on the server: the machine with the USB devices to share. You may be able to install usbip from your package manager. On...

Muon tomography (muography) is the practice of using muons generated by cosmic rays interacting with Earth’s atmosphere (or equivalent) to image structures on Earth’s surface, akin to producing an X-ray. In lieu of spending a lot of spending a fair bit of money on dedicated muon detectors, you can also hack such a device together with two Geiger-Müller tubes and related circuitry for about $100 or whatever you can source the components for. The reason for having two Geiger-Müller tubes is to filter out the countless other (much more prevalent) sources of ionizing radiation that we’re practically bathed in every second. Helped by a sheet of lead between both tubes, only a signal occurring at the same time from both tubes should be a muon. Specially cosmic ray muons, as these have significantly more kinetic energy that allows them to pass through both tubes. As a simple check it’s helpful to know that most of these muons will come from the direction of the sky. The author of the arti...

Camper shells are a time-honored piece of truck gear, but with modern trucks having increasingly vestigial beds, the length of your overnight abode has increasingly shrunk as well. To combat this problem, [Ed’s Garage] built a camper shell that extends once you’ve arrived at your campsite. [Ed] wanted to keep things relatively low profile while still tall enough to sit up in for convenience, leading to a small bit of the shell peeking over the truck’s roof. To keep the cold Canadian winter out, attention was paid to proper weather sealing around the sliding portion of the shell so that it stays warm and dry inside. While this would work on any truck, the mains power plugs in the bed of some modern trucks mean that certain glamping conveniences like a heater and projector can be easily powered while you’re in camp. We get to see the camper shell in action at the end of the video where the pros and cons of having your sleeping space also being your storage while  en route becom...

This week, Jonathan Bennett and Rob Campbell talk with Shimon Schocken about Nand2Tetris, the free course about building a computer from first principles. What was the inspiration for the course? Is there a sequel or prequel in the works? Watch to find out! Nand2Tetris Did you know you can watch the live recording of the show right on our YouTube Channel ? Have someone you’d like us to interview? Let us know, or contact the guest and have them contact us! Take a look at the schedule here . Direct Download in DRM-free MP3. If you’d rather read along, here’s the transcript for this week’s episode . Places to follow the FLOSS Weekly Podcast: Spotify RSS Theme music: “Newer Wave” Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License from Blog – Hackaday https://ift.tt/DbsiHoq

Picture a football (soccer ball) in your head and you probably see the cartoon ideal—a roughly spherical shape made with polygonal patches that are sewn together, usually in a familiar pattern of black and white. A great many balls were made along these lines for a great many decades. Eventually, though, technology moved on. Footballs got rounder, smoother, and more colorful. This was seen as a good thing, with each new international competition bringing shiny new designs with ever-greater performance. That was, until things went too far, and the new balls changed the game. Thus was borne the “knuckleball” phenomenon. Smoother Is Better, Right? An Adidas Telstar from the 1974 World Cup. The original Telstar design actually predates 1974, and the combination of 12 pentagonal and 20 hexagonal panels and black and white patterns had been used before, too. Regardless, the Adidas design was soon globally known, and eventually became the “default” design for a football in media. Credit...

[Martin] of [Wintergatan] is on a quest to create the ultimate human-powered, modern marble music machine. His fearless mechanical exploration and engineering work, combined with considerable musical talent, has been an ongoing delight as he continually refines his designs. We’d like to highlight this older video in which he demonstrates how to dynamically regulate the speed of a human-cranked music machine by taking inspiration from gramophones: he uses a flyball governor (or centrifugal governor). The faster the shaft turns, the harder the disk brake is applied. These devices are a type of mechanical feedback system that was invented back in the 17th century but really took off once applied to steam engines. Here’s how they work: weights are connected to a shaft with a hinged assembly. The faster the shaft spins, the more the weights move outward due to centrifugal force. This movement is used to trigger some regulatory action, creating a feedback loop. In a steam engine, the r...

Although a somewhat common feature on cars these days, tire pressure sensors (TPS) are also useful on bicycles. The SKS Airspy range of TPS products is one such example, which enables remote monitoring of the air pressure either to a special smartphone app (SKS MYBIKE) or to a Garmin device. Of course, proprietary solutions like this require reverse-engineering to liberate the hardware from nasty proprietary firmware limitations, which is exactly what [bitmeal] did with a custom firmware project . Rather than the proprietary and closed communication protocol, the goal was to use the open ANT+ sensor instead, specifically the (non-certified) TPS profile which is supported by a range of cycling computers. Before this could happen the Airspy TPS hardware had to be first reverse-engineered so that new firmware could be developed and flashed. These devices use the nRF52832 IC, meaning that development tools are freely available. Flashing the custom firmware requires gaining access to th...

[JanTec Engineering] was fascinated by the idea of using a 3D printer’s hot end to inject voids and channels in the infill with molten plastic , leading to stronger prints without the need to insert hardware or anything else. Inspiration came from two similar ideas: z-pinning which creates hollow vertical channels that act as reinforcements when filled with molten plastic by the hot end, and VoxelFill (patented by AIM3D) which does the same, but with cavities that are not uniform for better strength in different directions. Craving details? You can read the paper on z-pinning , and watch VoxelFill in (simulated) action or browse the VoxelFill patent . With a prominent disclaimer that his independent experiments are not a copy of VoxelFill nor are they performing or implying patent infringement, [JanTec] goes on to use a lot of custom G-code (and suffers many messy failures) to perform some experiments and share what he learned. Using an airbrush nozzle as a nozzle extension gain...