Using A Mirror To 3D Scan Both Sides Of An Object At Once

Photogrammetry is the process of 3D scanning an object by taking a lot of photographs, then using software to turn those into a 3D model. But the process can only scan what the camera can see, and one can’t always get a good view of every part of an object. To solve this, [Thomas Megel] shared an experiment in using a mirror to capture the underside of an object simultaneously with its top. The results were encouraging!

Using a mirror as the turntable allows the camera to image the underside at the same time.

To do this he perched a small tabletop gaming mini on a mirror serving as a turntable platform in his self-designed OpenScan Mini machine, which is designed to take highly structured photos of small objects for scanning purposes. This produced a single scan with two objects, the original and its mirror image, together in one file.

Aligning separate models and combining them into one is a common way to deal with partial or incomplete scans. The idea here is to get two scans at once, instead of separately with a reposition of the object in between. Additionally, it should be possible for the software to automatically separate, align, and combine the two since it is known exactly where the mirror plane is.

As far as a proof of concept, it’s encouraging. [Thomas] is still playing with the idea and looking for suggestions, so if you have any insights be sure to share them.

3D scanning can be a very useful tool, and while photogrammetry can be done with little more than your mobile phone’s camera, in some ways the concept is over a hundred years old.

Bilingual E-paper News Feed Helps Brush Up Language Skills

[Bob] recently completed LanguageLearner, a desktop device that increases his exposure to a second language by offering up bite-sized news items in Italian, with a complementary English translation. Even better, it’s a project made almost entirely from inexpensive parts he had on hand; it consists of little more than a Raspberry Pi Pico W, a 4.2″ E-paper display, and a 3D-printed stand.

Here’s how it works: once every few hours, the system wakes up and uses its WiFi connection to fetch news from an Italian RSS feed. Having chosen a slice of current events, it translates to English with an API call then displays both versions on the display: original Italian up top, translated English below.

Consisting of little more than a Raspberry Pi Pico W, an E-paper display, and a 3D-printed stand, it’s a great use of spare parts.

E-paper is ideal for a semi-passive project like this because once data is written to the display, there it remains without needing power or upkeep of any kind. Perfect for a device that only wakes up every few hours for an update before going right back to sleep.

Due to the limited RAM of the Raspberry Pi Pico [Bob] has to be purposeful about fetching data, so he relies on text from a simple RSS feed to avoid running out of memory while making web requests. The other minor quibble is that the driver for the display only handles plain ASCII; characters that cannot be rendered are displayed as grey boxes, which you can see in the image up top. Still, it gets the job done.

Increasing exposure to a language one is learning is beneficial, and people like to experiment. From trying to optimize human wait times by inserting language micro-lessons to a calculator that works in Toki Pona, technology offers new ways for folks to experiment with how we learn and play with language.

Improving An Aquarium Chiller With An Industrial Controller Transplant

A healthy aquarium ecosystem requires very specific conditions, with factors like the salinity and temperature having to be just right to keep said ecosystem happy. As some species are adapted to fairly cold water, this requires the use a water chiller. Recently [The Blunt Oracle] modified one of these aquarium-focused chillers with a much better controller to make it both more accurate and potentially more efficient as well.

The target for the surgery was a generic Shanhuchong Y-160 chiller that after a brief teardown turned out to use an STC-1000 style controller. The biggest disadvantage with this unit is probably that it just has one temperature probe, which monitored the temperature of the heat exchanger rather than that of the chilled water tank.

This controller was replaced with a Wi-Fi-equipped Elitech ECS-974T sourced for $50 off AliExpress that uses the same 71 x 29 mm form factor. Following that it was just a matter of some creative rewiring – as shown in the top image – and installing the twin temperature probes of the new controller.

Being able to monitor also the temperature of the chilled water adds a layer of redundancy that’s very welcome after splurging thousands of clams on a fancy aquarium and its inhabitants. As a bonus the Wi-Fi interface allows for it to be monitored and controlled remotely, with [The Blunt Oracle] pushing the Home Assistant configuration in a PR as well that recently got merged. They’d also like to extend their thanks to Elitech for having pretty good documentation that really helped with creating the HA configuration file, which is a rarity with many of such controllers.

Extract 3D Video Game Content By Firing Up Photo Mode

Here’s a pretty clever method [Dung3onlord] used to capture 3D scenes from a PlayStation 5 without needing any specialized software. All that’s needed is a series of high-resolution screenshots, and a few software tools.

The process is essentially photogrammetry, it just uses screenshots as the input instead of photographs.

Instead of sneakily yanking 3D assets from the runtime, he fires up the game’s photo mode on his PS5. By capturing an orbiting video of a static scene (making sure to hide the game’s user interface, something photo mode in games is good for) he ends up with a video file whose content — essentially a series of screenshots — can be used to reconstruct the original 3D scene. The workflow [Dung3onlord] uses has rather more steps, but conceptually that’s all there is to it.

The whole process is remarkably similar to photogrammetry, a method of turning a bunch of photographs from different angles into a 3D point cloud. We’ve seen photogrammetry used to digitize objects because point clouds can be turned into 3D models, essentially allowing one to 3D scan an object using little more than a digital camera.

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How To Install Haiku On A UEFI-Only Modern System

Recently Haiku has become a bit of a popular subject of articles and videos, owing perhaps to how close it currently is to be a daily-driver OS and fulfilling the dream that BeOS set out with. That said, there are still quite a few hurdles before that glorious era can fully commence, with a video by [Ex-IT guy] on YouTube demonstrating some of the major hurdles by installing Haiku on Ryzen 3-based MiniPC that only supports UEFI boot.

Installing the UEFI bootloader is still a very much manual process with the user required to create UEFI boot and OS partitions before copying the bootloader into UEFI boot partition. After this Haiku can be installed as normal. The other variation of multi-boot is demonstrated in the video, with Haiku installed alongside Windows and Linux. This requires a more complex directory layout in the UEFI boot partition.

The other major hurdle with Haiku comes after the system boots into the OS following installation, with no driver available for the Vega-based iGPU as AMD GPU support peters out around the GCN 2 era for now. Without accelerated graphics the utility of an OS is quite diminished, but fortunately this seems to be a fixable issue considering that Linux has the appropriate GPU support.

Meanwhile features like sound worked out of the box, which makes it arguably a more pleasant experience than installing Haiku on a 2009 Mac Mini. It’s also very easy to port software from Linux to Haiku, often with very few changes since it has all the typical POSIX things.

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This Front Panel Makes Its Own Clean-Edged Drill Guides

We haven’t seen an instrument panel quite like [bluesyann]’s, which was made by curing UV resin directly onto plywood with the help of a 3D printer and a bit of software work. The result is faintly-raised linework that also makes hand drilling holes both cleaner and more accurate.

The process begins by designing the 2D layout in Inkscape, which has the advantage of letting one work in 1:1 dimensions. A 10 mm diameter circle will print as 10 mm; a nice advantage when designing for physical components. After making the layout one uses OpenSCAD to import the .svg and turn it into a 3D model that’s 0.5 mm tall. That 3D model gets loaded into the resin printer, and the goal is to put it directly onto a sheet of plywood.

A little donut shape makes a drill centering feature, and the surrounding ring keeps the edges of the hole clean.

To do that, [bluesyann] sticks the plywood directly onto the 3D printer’s build platform with double-sided tape. With the plywood taking the place of the usual build surface, the printer can cure resin directly onto its surface. Cleanup still involves washing uncured resin off the board, but it’s nothing a soak in isopropyl alcohol and an old toothbrush can’t take care of.

[bluesyann] has a few tips for getting the best results, and one of our favorites is a way to make drilling holes easier and cleaner. Marking the center of a drill hit with a small donut-shaped feature makes a fantastic centering guide, making hand drilling much more accurate. And adding a thick ring around the drill hole ensures clean edges with no stray wood fibers, so no post-drilling cleanup required. Don’t want the ring to stick around after drilling? Just peel it off. There’s a load of other tips too, so be sure to check it out.

A nice front panel really does make a project better, and we’ve seen many different approaches over the years. One can stick laminated artwork onto an enclosure, or one can perform toner transfer onto 3D printed surfaces by putting the design on top of the 3D printer’s build surface, and letting the heat of molten plastic do the work of transferring the toner. And if one should like the idea of a plywood front panel but balk at resin printing onto it, old-fashioned toner transfer works great on wood.

Making A Nichrome Wirewound Power Resistor

Although not really a cost-effective or a required skill unless you have some very specific needs not met by off-the-shelf power resistor options, making your own own wirewound power resistor is definitely educational, as well as a fascinating look at a common part that few people spare a thought on. Cue [TheElectronBench]’s video tutorial on how to make one of these components from scratch.

The resistance value is determined by the length of nichrome wire, which is an alloy of nickel and chromium (NiCr) with a resistivity of around 1.12 µΩ/m. It’s also extremely durable when heated, as it forms a protective outer layer of chromium oxide. This makes it suitable for very high power levels, but also requires the rest of the power resistor assembly to be able to take a similar punishment.

For the inner tube of this DIY power resistor a tube of alumina ceramic was used, around which the nichrome wire is wound. This resistor targets 15 Ohm at a maximum load of 50 Watt, this means a current of about 1.83 A is expected at 27.4 V. The used nichrome wire has a measured resistance of 10.4 Ohm, ergo 1.44 meter has to be cut and wound.

This entire assembly is then embedded in refractory cement (fireproof cement), as this will keep the wire in place, while also able to take the intense temperature cycling during operation. As a bonus this will prevent toasting the surrounding environment too much, never mind lighting things on fire as the nichrome wire heats up.

As explained in the video, this is hardly the only way to create such a power resistor, with multiple types of alternative alloys available, different cores to wind around and various options to embed the assembly. The demonstrated method is however one that should give solid results and be well within the capabilities and budget of a hobbyist.

An important point with nichrome is that you cannot really solder to it, so you’ll need something along the lines of a mechanical (crimping) connection. There are also different winding methods that can affect the inductance of the resistor, since this type of resistor is by its design also a coil. This is however not covered in the video as for most applications it’s not an issue.

Overall, this video tutorial would seem to be a solid introduction to nichrome power resistors, including coverage of many issues you may encounter along the way. Feel free to sound off in the comment section with your own experiences with power resistors, especially if you made them as well.