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

June 2, 2026 by Donald Papp 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.

The Uncooperative Mirror Will Not Help You

May 30, 2026 by Jenny List 7 Comments

The value of a mirror is in its clarity. If the reflection is cast by [danicakostic17]’s Uncooperative Mirror though, you’ll find anything but. It’s described as a useless machine, because it appears as a tiled mirror. As you approach it though, the tiles shake around and make it very difficult to follow what’s in front of you. It’s an art piece and a prank all in one, and we like it.

Behind the mirror is a 3D printed frame and a set of small servos with what look like some belts to hitch them up. There’s an ultrasonic sensor and an Arduino Uno, that sets those servos going as soon as the ultrasonic sensor sees anything. We can see this thing would be fun at a party.

Everything you’ll need is on the Instructables page linked above should you be foolhardy enough to want your own, and there’s even a YouTube video which we’ve placed below.

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Making A Bronze Mirror From Scratch

April 17, 2026 by Maya Posch 18 Comments

Although modern-day silvered glass mirrors have pretty much destroyed the market for bronze mirrors, these highly polished pieces of metal once were the pinnacle of mirror technology. Due to the laborious process required these mirrors saw use essentially only by the affluent. That said, how hard would it be to make a bronze mirror today with all of the modern technologies that even a hobbyist can acquire for their shed? Cue [Lundgren Bronze Studios] giving it a shot, starting by casting something flat-ish to start polishing.

Just getting that initial shape to start polishing is a chore, with hammering out the shape possibly being also a viable method. When casting metal it’s tricky to avoid having air bubbles and other defects forming, though using a sand mold seems to help a lot.

After you have the rough shape, polishing using power tools seems like cheating, but as you can see in the video even going from 50 to 8000 grit with a rotating disc left countless scratches. Amusingly, hand sanding did a much better job of removing the worst scratches, following which a polishing compound helped to bring out that literal mirror finish.

A quick glance at the Wikipedia entry for bronze mirrors shows that a tin-bronze alloy like speculum metal was used for thousands of years as it was much easier to polish to a good mirror finish. The metallurgy of what may seem like just a vanity item clearly goes deeper than just polishing up a metal surface.

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Spin-Casting This Telescope Mirror In Resin Didn’t Go To Plan

June 3, 2025 by Zoe Skyforest 29 Comments

For most of us, mirrors are something we buy instead of build. However, [Unnecessary Automation] wanted to craft mirrors of his own for a custom telescope build. As it turns out, producing optically-useful mirrors is not exactly easy.

For the telescope build in question, [Unnecessary Automation] needed a concave mirror. Trying to get that sort of shape with glass can be difficult. However, there’s such a thing as a “liquid mirror” where spinning fluid forms into a parabolic-like shape. Thus came the idea to spin liquid resin during curing to try and create a mirror with the right shape.

That didn’t quite work, but it inspired a more advanced setup where a spinning bowl and dense glycerine fluid was used to craft a silicone mold with a convex shape. This could then be used to produce a resin-based mirror in a relatively stationary fashion. From there, it was just necessary to plate a shiny metal layer on to the final part to create the mirror effect. Unfortunately, the end result was too messy to use as a viable telescope mirror, but we learn a lot about what didn’t work along the way.

The video is a great journey of trial and error. Sometimes, figuring out how to do something is the fun part of a project, even if you don’t always succeed. If you’ve got ideas on how to successfully spin cast a quality mirror, drop them in the comments below. We’ve seen others explore mirror making techniques before, too.

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Adaptive Optics Take Clearest Pictures Of The Sun Yet

June 1, 2025 by Bryan Cockfield 9 Comments

It’s sometimes easy to forget that the light in the sky is an actual star. With how reliable it is and how busy we tend to be as humans, we can take that incredible fact and stow it away and largely go on with our lives unaffected. But our star is the thing that gives everything on the planet life and energy and is important to understand. Humans don’t have a full understanding of it either; there are several unsolved mysteries in physics which revolve around the sun, the most famous of which is the coronal heating problem. To help further our understanding a number of scientific instruments have been devised to probe deeper into it, and this adaptive optics system just captures some of the most impressive images of it yet.

Adaptive optics systems are installed in terrestrial telescopes to help mitigate the distortion of incoming light caused by Earth’s atmosphere. They generally involve using a reference source to measure these distortions, and then make changes to the way the telescope gathers light, in this case by making rapid, slight changes to the telescope’s mirror. This system has been installed on the Goode Solar Telescope in California and has allowed scientists to view various solar phenomena with unprecedented clarity.

The adaptive optics system here has allowed researchers to improve the resolution from the 1000 km resolution of other solar telescopes down to nearly the theoretical limit of this telescope—63 km. With this kind of resolution the researchers hope that this clarity will help shine some light on some of the sun’s ongoing mysteries. Adaptive optics systems like this aren’t just used on terrestrial telescopes, either. This demonstration shows how the adaptive optics system works on the James Webb Space Telescope.

Thanks to [iliis] for the tip!

DIY Solar Generator Inspired By James Webb Telescope

May 30, 2025 by Zoe Skyforest 36 Comments

If you look at this solar generator from [Concept Crafted Creations], you might think it’s somehow familiar. That’s because the design was visually inspired by the James Webb Space Telescope, or JWST. Ultimately, though, it’s purpose is quite different—it’s designed to use mirrors to collect and harness solar energy. It’s not quite there yet, but it’s an interesting exploration of an eye-catching solar thermal generator.

To get that JWST look, the build has 18 mirrors assembled on a 3D printed frame to approximate the shape of a larger parabolic reflector. The mirrors focus all the sunlight such that it winds up heating water passing through an aluminum plate. Each mirror was custom made using laser cut acrylic and mirror film. Each mirror’s position and angle can be adjusted delicately with screws and a nifty sprung setup, which is a whole lot simpler than the mechanism used on the real thing. The whole assembly is on a mount that allows it to track the movement of the sun to gain the most sunlight possible. There’s a giant laser-cut wooden gear on the bottom that allows rotation on a big Lazy Susan bearing, as well as a servo-driven tilting mechanism, with an Arduino using light dependent resistors to optimally aim the device.

It’s a cool-looking set up, but how does it compare with photovoltaics? Not so well. The mirror array was able to deliver around 1 kilowatt of heat into the water passing through the system, heating it to a temperature of approximately 44 C after half an hour. The water was warmed, but not to the point of boiling, and there’s no turbines or anything else hooked up to actually take that heat and turn it into electricity yet. Even if there were, it’s unlikely the system would reach the efficiency of a similarly-sized solar panel array. In any case, so far, the job is half done. As explained in the build video, it could benefit from some better mirrors and some structural improvements to help it survive the elements before it’s ready to make any real juice.

Ultimately, if you need solar power fast, your best bet is to buy a photovoltaic array. Still, solar thermal is a concept that has never quite died out.

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A Dual Mirror System For Better Cycling Safety

May 1, 2025 by Donald Papp 54 Comments

Rear-view mirrors are important safety tools, but [Mike Kelly] observed that cyclists (himself included) faced hurdles to using them effectively. His solution? A helmet-mounted dual-mirror system he’s calling the Mantis Mirror that looks eminently DIY-able to any motivated hacker who enjoys cycling.

One mirror for upright body positions, the other for lower positions.

Carefully placed mirrors eliminate blind spots, but a cyclist’s position changes depending on how they are riding and this means mirrors aren’t a simple solution. Mirrors that are aligned just right when one is upright become useless once a cyclist bends down. On top of that, road vibrations have a habit of knocking even the most tightly-cinched mirror out of alignment.

[Mike]’s solution was to attach two small mirrors on a short extension, anchored to a cyclist’s helmet. The bottom mirror provides a solid rear view from an upright position, and the top mirror lets one see backward when in low positions.

[Mike] was delighted with his results, and got enough interest from others that he’s considering a crowdfunding campaign to turn it into a product. In the meantime, we’d love to hear about it if you decide to tinker up your own version.

You can learn all about the Mantis Mirror in the video below, and if you want to see the device itself a bit clearer, you can see that in some local news coverage.

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