Infinity Mirror At Warp Speed

September 11, 2020 by Brian McEvoy 10 Comments

Inventing often combines more than one old ideas into a new one. Even when the fused things are similar, the result can be more valuable than the sum of its parts. Unlike those analog watches with a digital clock below the face, when [Mojoptix] combined the re-reflecting properties of an infinity mirror with the image twisting qualities of a funhouse mirror, we get more than just a pair of mirrors. The resulting images look like a lot of fun. Warping one surface of two parallel mirrors doesn’t just alter the result a bit, because the planes feed off each other’s view, the final product is an exponentially skewed show.

Our host mounts a 3D printed ring with an hubward-facing strip of LEDs to an ordinary glass mirror. Over that, he designs four mated plates that hold semi-reflective film sheets in different shapes. The first is a hyperbolic paraboloid, but it’s probably easier to think of it as shaped like a Pringles chip (crisp). Once the light is applied, it looks like a bowtie made by a deranged god or the start of an infinite rabbit hole of light and reflection. To further the madness, he hits us with four shapes at once, so we hope you’ll take a moment to enjoy the video below.

This guy is no stranger to optics, and we’ve reported on a couple of other cool inventions that teach a concept through demonstration. His precision calipers demonstrate the Moiré effect, and his digital sundial capitalizes on parallel light beams.

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500 Lasers Are Not Necessarily Better Than One, But They Look Great

July 13, 2020 by Dan Maloney 29 Comments

If playing with but a single laser pointer is fun, then playing with 500 laser pointers must be 500 times the fun, right? So by extension, training 500 laser pointers on a single point must be the pinnacle of pointless mirth. And indeed it is.

When we first spotted this project, we thought for sure it was yet another case of lockdown-induced boredom producing an over-the-top build. Mind you, we have no problem with that, but in this case, [nanoslavic] relates that this is actually a project from a few years back. It’s really as simple as it looks: 500 laser pointer modules arranged on a plate with a grid of holes in a 25 by 20 array. As he placed the laser modules on the board with a glob of hot glue, he carefully aimed each one to hit a single point about a meter and a half away. There are also a handful of blue LEDs nestled into the array, because what project is complete without blue LEDs?

The modules are wired in concentric circuits and controlled by a simple bank of toggle switches. Alas, 500 converging ~~150-mW~~ 5 mW lasers do not a ~~75-W~~ 2.5 W laser make; when fully powered, the effect at the focal point is reported to be only a bit warm. But it looks incredible, especially through smoke. Throwing mirrors and lenses into the beam results in some interesting patterns, too.

You’ll still need to take safety seriously if you build something like this, of course, but this one is really just for show. If you’re really serious about doing some damage with lasers, check out the long list of inadvisable laser builds that [Styropyro] has accumulated — from a high-powered “lightsaber” to a 200-Watt laser bazooka.

(Terminate your beams carefully, folks. We don’t want anyone going blind.)

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Variable Mirror Changes Shape Under Pressure

June 27, 2020 by Dan Maloney 10 Comments

Unless you’re in a carnival funhouse, mirrors are generally dead flat and kind of boring. Throw in some curves and things get interesting, especially when you can control the curve with a touch of your finger, as with this variable surface convex mirror.

The video below starts off with a long but useful review of conic constants and how planes transecting a cone can create circles, parabolas, or ellipses depending on the plane’s angle. As [Huygens Optics] explains, mirrors ground to each of these shapes have different properties, which makes it hard to build telescopes that work at astronomical and terrestrial distances. To make a mirror that works over a wide range of distances, [Huygens Optics] built a mirror from two pieces of glass bonded together to form a space between the front and rear surface. The front surface, ground to a spherical profile, can be deformed slightly by evacuating the plenum between the two surfaces with a syringe. Atmospheric pressure bends the thinner front surface slightly, changing the shape of the mirror.

[Huygens Optics] also built an interferometer to compare the variable mirror to a known spherical reference. The data from the interferometer was fed to a visualization package that produced maps of the surface shape, which you can easily see changing as the pressure inside the mirror changes. Alas, a deeper dive into the data showed the mirror to be less than perfect, but it’s fascinating to think that a mirror can flex enough to change from elliptical to almost parabolic with nothing more than a puff of air.

We’ve seen a couple of interesting efforts from [Huygens Optics] before, including this next-level spirit level. He’s not all about grinding glass, though — witness this investigation into discriminating metal detectors.

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An Easy Hack For Working With Your Hands On Video Calls

May 19, 2020 by Lewin Day 7 Comments

Video calls are okay. While some advocate for the benefit of body language over a standard phone call, they remain an imperfect substitute for in-person interaction. [Amos] wanted to be able to demonstrate things better when on a video chat, so devised this simple solution for when he’s working with his hands.

The hack consists of a mirror attached to a clothespeg with a flexible piece of wire. This simple device can then be clipped to the screen of a laptop, and the mirror adjusted to allow the webcam to view the user’s desk. By positioning it correctly, the user can both show their desk and their face together, in split screen. It’s a great way to explain something while giving viewers a clear shot of your face and your hands at the same time.

It’s not exactly complicated, but a nifty hack that could prove useful to anyone trying to teach without having to muck about with complicated digital handwriting setups or multiple webcams. There’s a shortage at the moment, anyway. If you’re looking for a way to chat with your less tech savvy relatives, consider repurposing an old Android tablet. Video after the break.

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A Rough And Ready Pan & Tilt Mirror

June 25, 2019 by Lewin Day 8 Comments

There’s nothing quite like waking up on a warm and sunny morning, with the sun filtering in through the windows over a magnificent beach view. Of course, in real life, not every bedroom has access to beautiful natural vistas and abundant natural light. [Rue Mohr] decided to try and solve this issue with technology.

The initial write-up may be brief, but the pictures of the resulting project show a proper hacker’s build. A stand for an old office chair appears to serve as the base, and the mirror is mounted on a frame that allows for both pan and tilt to be adjusted. There’s a large gear to enable pan rotation, which meshes with a nifty old-school cage gear built out of what we suspect is plastic and welding rod. An AVR microcontroller is charged with running the show, with it interpolating a series of waypoints to set the mirror’s position throughout the day.

[Rue] reports that the project is nearing completion, and is soon to be fully automated. With the dark bedroom that spawned the project no longer a concern, the mirror will instead be pressed into service to provide sun to a row of bean plants.

If you’re looking for a pan-tilt mechanism, but something a little smaller, this 3D-printed mechanism might be just what you’re after.

Text Projector With — You Know — Lasers

February 14, 2019 by Al Williams 9 Comments

We missed [iliasam’s] laser text projector when it first appeared, perhaps because the original article was in Russian. However, he recently reposted in English and it really caught our eye. You can see a short video of it in operation, below.

The projector uses raster scanning where the beam goes over each spot in a grid pattern. The design uses one laser from a cheap laser pointer and a salvaged mirror module from an old laser printer. The laser pointer diode turned out to be a bit weak, so a DVD laser was eventually put into service. A DVD motor also provides the vertical scan which is just a slight wobble of a mirror. A Blue Pill CPU provides all the smarts. You can find the code on GitHub.

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Magic Mirror Tirelessly Indulges Children’s Curiousity

May 27, 2018 by Donald Papp 6 Comments

[pepelepoisson]’s Miroir Magique (“Magic Mirror”) is an interesting take on the smart mirror concept; it’s intended to be a playful, interactive learning tool for kids who are at an age where language and interactivity are deeply interesting to them, but whose ceaseless demands for examples of spelling and writing can be equally exhausting. Inspiration came from his own five-year-old, who can neither read nor write but nevertheless has a bottomless fascination with the writing and spelling of words, phrases, and numbers.

The magic is all in the simple interface. Magic Mirror waits for activation (a simple pass of the hand over a sensor) then shows that it is listening. Anything it hears, it then displays on the screen and reads back to the user. From an application perspective it’s fairly simple, but what’s interesting is the use of speech-to-text and text-to-speech functions not as a means to an end, but as an end in themselves. A mirror in more ways than one, it listens and repeats back, while writing out what it hears at the same time. For its intended audience of curious children fascinated by the written and spoken aspects of language, it’s part interactive toy and part learning tool.

Like most smart mirror projects the technological elements are all hidden; the screen is behind a one-way mirror, speakers are out of sight, and the only inputs are a gesture sensor and a microphone embedded into the frame. Thus equipped, the mirror can tirelessly humor even the most demanding of curious children.

[pepelepoisson] explains some of the technical aspects on the project page (English translation link here) and all the code and build details are available (in French) on the project’s GitHub repository. Embedded below is a demonstration of the Magic Mirror, first in French then switching to English.

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