Kritik sah

Bluetooth is a short-range protocol that’s great for peripherals and finding your keys, but it’s limited range is mainly a product of how it’s usually implemented. A recent video from [nktbuilds] demonstrates this by extending its range out to 12 kilometers, or around 7.5 miles. The secret is twofold: one is the antenna, a parabolic unit that captures far more than the dinky dipole in your phone. The other is a very sensitive receiver with a much lower noise floor. What you won’t see here is any extra power than you get stock out of one of those generic coin-sized Bluetooth tracker tags. It’s kind of obvious, in retrospect: grab more signal, lower your noise floor, and get a better result. Still, it certainly wasn’t obvious it would work out to 1200 m, and it’s an impressive feat by [nktbuilds]. We’re going to have to keep it in mind next time we lose our keys. Of course this doesn’t mean you should jump to Bluetooth for distance...

The Nintendo DSi was released in November 2008, and boasted a new feature not formerly seen on the brand’s handhelds—it had two cameras, inside and outside. It let the console take photos, a feature rather fitting given it was an era in which phone cameras had become the norm. Only, it wasn’t so good out of the box. However, [gavff] recently found an accessory from way back when that aimed to make the DSi’s camera somewhat more capable. For some reason, the console accessories company Nyko decided that that the Nintendo DSi deserved an 8x optical zoom lens. Never mind that the console’s cameras were limited to a resolution of just 640 x 480 pixels, it was deemed important that the handheld have the ability to capture images of things that were somewhat farther away. The lens mounted to a specially-designed case that fit around the original DSi’s shell. It’s not particularly clear what the intended use case was, but if you wanted to expand the capabil...

There are two kinds of cyberdeck: the kind someone makes on a lark and operates purely on ‘rule of cool’, and the kind designed to do practical work. The Slurptop by [Slurpburgers] is decidedly in the second category — but that doesn’t mean it lacks for coolness. What’s cooler than a power-tool battery? Don’t you just want to slurp that up? That last feature might make this closer to the Neuromancer definition of cyberdeck than most featured on these pages. You still can’t jack it into your cortex, but it does have the ‘assemble from off the shelf components at need’ vibe of the original concept. It also means there should be plenty of battery power to keep working with the power-hungry x86-based GMKtec MiniPC that runs this thing. If the battery gets low, which it will after about 4 hours or so, swapping is easy — but not hot swapping. Luckily [Slurpburgers] grabbed a module meant for Uninterruptible Power Supplies to sw...

These days we take high-speed networking for granted, but it can be difficult to get vintage computers talking to modern machines. To help solve this problem [jaime] came up with Meatloaf which can provide files to a Commodore regardless of their location or medium of storage. Meatloaf is an ESP32 device at its core, which plugs in to any of several Commodore computers through their IEC serial port. Many similar systems exist to bridge the gap between the modern world and the now-retro one, but this one connects to a dedicated service which points towards files no matter where they’re stored. There is some local storage, but it can also retrieve files from any active URL, and Meatloaf retrieves the files and then sends them to the Commodore over that serial link. Part of what makes this unique is that the user doesn’t need to configure Meatloaf in any particular way, everything is done from the Commodore as long as the URL is known to the user. The system can even parse n...

The 0.5 mm Benchy made with the MicroRepRap UV head. The RepRapMicron (also µRepRap) is pretty much the microscopic take on what RepRap did for more macroscale manufacturing, with the most recent innovation being a UV print head, called the PIKA UV Head . What this does is use off-the-shelf optical fiber and UV LED modules to create 3D structures in-situ in a UV resin, allowing for pretty small structures to be printed, down to a resolution of about 9 µm. More photos of prints can be found on the blog page with links to YouTube videos. It’s naturally somewhat tricky to get clean photographs of a 3D print that’s small enough to lose forever if you so much as sneeze or breathe too loudly. For the UV head assembly a single mode fiber optical cable was used in the form of a regular patch cord that got trimmed a bit with a hacksaw. This was used in combination with a “3W” UV LED module, which may or may not be its true rating, but it was definitely able to cure th...

Anyone who’s ever built their own motors knows how tedious winding the coils soon becomes; in [Larry]’s case, the issue was even worse. He’s building his own flip-dot matrix display, and each dot uses two electromagnetic coils to flip a magnet in the dot. Rather than wind each of these by hand, therefore, he built his own coil-winding machine . The coil winder uses two stepper motors: one to wind wire onto the bobbin, and one to move the wire guide carriage back and forth, distributing the wire evenly across the bobbin. The bobbin is held in place by a retainer, which doubles as a tie point for the end of the wire. The spool of wire rotates on a pair of bearings, and the wire is fed between two pieces of foam to provide adjustable tension. The housing is mostly 3D-printed, with some metal rods, bearings, and belt drives fleshing out the structure. On the electronics side, a Teensy controls the winder, with an OLED display and a rotary encoder for control. Before beginning on a coil, ...

The Chinese had been using large crossbows – akin to Greek and Roman ballistae – for warfare for many of the same reasons that European armies loved them. Their single, large arrow was effectively unstoppable, though this also was rather useless against large groups of infantry unless they were so kind to neatly line up. Old Chinese records mention a special kind of ammunition, called a cup arrow, or ‘storm of crows’, which involves launching many smaller arrows instead of a single large one, a feat that [Tod] really wanted to try and recreate . In itself this doesn’t sound too complex: just grab some arrows, loosely tie them together in a bundle and slap them on the crossbow. Yet with the immense forces applied on this bundle it clearly turns out that the engineering challenge isn’t quite that straightforward, as the arrows love to scatter wildly in all directions or otherwise be rather unpredictable. Although we can find historical references to ...