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

June 2, 2026 by 28 Comments

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.

Cookies, Baked The 3D Printer Way

June 2, 2026 by 20 Comments

Imagine for a moment that the Cookie Monster is going to visit, but all the cookie baking utensils in your house have been mislaid. The horror! Fortunately [Startup Chuck] is here with a video showing the process of baking cookies in a 3D printer, and as an extra treat he’s using entirely 3D printed utensils too.

The utensils are comprehensive array of all you’d need for serious cookie production, even going as far as to print a mixing bowl and beater for a KitchenAid mixer. There are scoops aplenty, and something we’re particularly impressed with, a spatula with a TPU blade. We’re guessing that FDM prints might not be the best for cooking because all manner of food could get caught in those layer lines and go off, but let’s face it, this is a bit of fun rather than a forever cooking project. We like the AI generated spork for its near-flatness, reminding us of our AI-generated breakfast. Finally he even prints a cookie baking sheet using nylon filament.

An enclosed 3D printer makes a surprisingly effective low-temperature oven, with the heated bed as the element. It works, and makes recognizable cookies, though they’re not browned. As entertaining as this experiment may be, we can’t recommend following his example — at the very least, moisture and food ingredients in your printer probably aren’t conducive to good future printing.

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Restoring Apple’s Terrible But Awesome IBook Laptop

June 1, 2026 by 16 Comments

Before the Apple MacBook there was the Apple iBook, fruity 1999 colors included. These PowerPC-based laptops targeted low-cost PC-compatible laptops much like the iMac did, albeit it the latter with more success. That said, these laptops are said to be a nightmare to repair, so when [This Does Not Compute] got his hands on a shiny first generation, 300 MHz PowerPC powered, tangerine-colored one, he somewhat dreaded trying to fix it.

Aside from some relatively minor cosmetic issues such as typical cracks in the plastic and a missing optical drive door it seemed in good condition. The first issue came on boot, when MacOS 9.0 would throw up an error message about an issue with cache memory. After booting into the OS this cache memory did indeed show up as missing. Next issue was the optical drive doing absolutely nothing and restarting leading to the system locking up and not starting until plugging in the power adapter.

Fortunately the optical drive started working after addressing a software issue, but the power and cache issues were concerning. Cue a long troubleshooting and repair session that involved purchasing a ‘parts unit’ from Japan to merge both into a single iBook with hopefully a working system at the end.

Along the way the reason why people dislike maintaining these systems, as to do something like getting to the hard drive requires removing the entire display. The cause for the first iBook’s problems also seemed to be due to a liquid spill of some type, as on boot there was no chime either, indicating a wider board-level issue. Unfortunately this was left further undiagnosed and the Japanese mainboard used instead. It’d be interesting to see the deeper cause, but most likely the mainboard will be used for components.

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After The Dust Settles: Building Pebble Apps

June 1, 2026 by 15 Comments

For a piece of wearable technology, Pebble has had a fairly “rocky” history. One of the most successful Kickstarters of its era, it went on to get acquired by FitBit, quietly shelved by them, then acquired by Google and open-sourced, where it’s now somewhat back in the hands of its original creator. Its new open source nature means that regular people can develop for these popular watches again, and [Coconauts] have developed a guide for these watches, new and old.

The original watches had to be coded using C, which is a fundamental language but one that generally isn’t used much in the modern world outside of embedded systems and other areas where efficieny is important. C does much less hand-holding than modern languages, so there are a number of things to keep an eye on when coding for these watches that languages like Rust, Go, and Python handle on their own. Regardless, the two-person team recently built a pair of apps for the Pebble platform as part of an app-making contest, one which notifies the user that the watch is charged to 80%, and another that shows an interactive kitten on the watch’s face.

Both of the apps are available from the Pebble app repository, and from there the source code can be found on respective GitHub pages if you’re looking for some examples to dust off old C skills. If you happen to have an old Pebble watch or always wanted one but didn’t want to deal with FitBit, now might be a good time to get them out and start tinkering around with it since it’s now in the open-source domain.

Bilingual E-paper News Feed Helps Brush Up Language Skills

June 1, 2026 by 3 Comments

[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.

On The Wisdom Of Replacing A NiMH Module In A Prius Battery Pack

June 1, 2026 by 81 Comments
Old versus new Prius NiMH module. (Credit: HubNut, YouTube)
Old versus new Prius NiMH module. (Credit: HubNut, YouTube)

It’s possible to get a pretty good deal on used Toyota Prius cars, but as with all hybrid cars that also means a used battery pack and resulting issues. In the case of the Gen 2 Prius that [HubNut] recently acquired it was clear that its battery was effectively toast, with the engine running constantly and the car often giving up due to detected issues with the pack. After getting to an EV-focused garage for repairs, a spare NiMH module was used to replace a problematic module to bring it back to good health, while raising the question of how sensible such a repair is.

Certainly, compared to the average BEV where a much larger battery is generally integrated well into the frame, a Prius makes things very easy, with the compact battery readily accessible and removable from the trunk. It is also a very modular battery, with some elbow grease and bolt-twisting enough to disassemble it.

Even with that it still a high-voltage battery with all the associated risks, and as raised in the comments there’s a big question about putting a new(er) cell into a pack with more worn-out NiMH cells as generally the cells wear out fairly evenly. While this fix can give the pack some more life, the new cell won’t match the internal resistance and other parameters of the pack, leading to issues like voltage drift. Then there’s the issue that if one cell failed, others probably aren’t far behind, so this hack would soon become a regular ritual.

Much like swapping one bad 18650 Li-ion cell in a bigger battery, it’s probably a more sustainable solution to simply replace the entire battery at once, or at least replace all modules or cells to properly refurbish it. For [HubNut] this fix suffices because he suspects that this pack was already assembled from random modules, it’s an important consideration to make if you don’t enjoy ending up stranded during a trip.

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Know Your Food: Cheesemaking

June 1, 2026 by 78 Comments

There’s a thing that people who grew up on farms all share: a connection with food production that isn’t some mystical rose-tinted woo from a TV chef, but instead a practical general knowledge from being there on the ground. A glance at a crop in a field and you immediately recognise what it is, if it’s ploughing time you’ll know the soil type, and there’s always either too little, or too much rain. For a given foodstuff you’ll know far too much about where it came from, because if your dad wasn’t involved in its production, the chances are someone he knew was. You take this for granted, after all doesn’t everyone have this general knowledge? Seemingly not.

Hackaday is not a cooking channel, but I know we’re all interested here in how things are made. Shouldn’t that also extend to what we eat? It’s fashionable to follow a back-to-nature line that all commercial foodstuffs are somehow over-processed junk, but without the requisite knowledge you’re flying blind there. To know both how common foodstuffs should be made, as well as how they are made industrially, should be an essential for everyone.

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