Blind Camera: Visualizing A Scene From Its Sounds Alone

June 12, 2023 by Maya Posch 4 Comments

A visualization by the Blind Camera based on recorded sounds and the training data set for the neural network. (Credit: Diego Trujillo Pisanty)

When we see a photograph or photo of a scene, we can likely imagine what sounds would go with it, but what if this gets inverted, and we have to imagine the scene that goes with the sounds? How close would we get to reconstructing the scene in our mind, without the biases of our upbringing and background rendering this into a near-impossible task? This is essentially the focus of a project by [Diego Trujillo Pisanty] which he calls Blind Camera.

Based on video data recorded in Mexico City, a neural network created using Tensorflow 3 was trained using an RTX 3080 GPU on a dataset containing frames from these videos that were associated with a sound. As a result, when the thus trained neural network is presented with a sound profile (the ‘photo’), it’ll attempt to reconstruct the scene based on this input and its model, all of which has been adapted to run on a single Raspberry Pi 3B board.

However, since all the model knows are the sights and sounds of Mexico City, the resulting image will always be presented as a composite of scenes from this city. As [Diego] himself puts it: for the device, everything is a city. In a way it is an excellent way to demonstrate how not only neural networks are limited by their training data, but so too are us humans.

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Detail of a circuit sculpture in the shape of a lighthouse

Op Amp Contest: This Lighthouse Sculpture Flickers In The Rhythm Of Chaos

June 6, 2023 by Robin Kearey 7 Comments

Op amps are typically used to build signal processing circuits like amplifiers, integrators and oscillators. Their functionality can be described by mathematical formulas that have a single, well-defined solution. However, not every circuit is so well-behaved, as Leon Chua famously showed in the early 1980s: if you make a circuit with three reactive elements and a non-linear component, the resulting oscillation will be chaotic. Every cycle of the output will be slightly different from its predecessors, and the circuit might flip back and forth between different frequencies.

A light modulated with a chaotic signal will appear to flicker like a candleflame, which is the effect [MaBe42] was looking for when he built a lighthouse-shaped circuit sculpture. Its five differently-colored LEDs are driven by a circuit known as Sprott’s chaotic jerk circuit. A “jerk”, in this context, is the third-order derivative of a variable with respect to time – accordingly, the circuit uses three RC integrators to implement its differential equation, along with a diode to provide nonlinearity.

The lighthouse has three chaotic oscillators, one in each of its legs. Their outputs are used to drive simple pulse-width modulators that power the LEDs in the top of the tower. [MaBe42] used the classic LM358 op amp for most of the circuits, along with 1N4148 diodes where possible and 1N4004s where needed – not for their higher power rating, but for their stronger leads. As is common in circuit sculptures, the electronic components are also part of the tower’s structure, and it needs to be quite sturdy to support its 46 cm height.

[MaBe42] used 3D printed jigs to help in assembling the various segments, testing each circuit before integrating it into the overall structure. The end result is a beautiful ornament for any electronics lab: a wireframe structure with free-hanging electronic components and randomly flickering lights on top. Want to learn more about circuit sculpture? Check out this great talk from Remoticon 2020.

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Front and back views of a square, purple PCB with op amps and BNC outputs

Op Amp Contest: Generate Spirograph Shapes Using Only Op Amps And Math

June 5, 2023 by Robin Kearey 13 Comments

If you’re a child of the ’80s or ’90s, chances are you’ve spent hours tracing out intricate patterns using the pens and gears of a Spirograph kit. Simple as those parts may be, they’re actually a very clever technique for plotting mathematical functions called hypotrochoids and epitrochoids. [Craig] has spent some time analyzing these functions, and realized you can also implement them with analog circuits. He used this knowledge to design a device called Op Art which generates Spirograph shapes on your oscilloscope using just a handful of op amps.

To draw either a hypotrochoid or an epitrochoid, you need to generate sine and cosine waves of various frequencies, and then add them with a certain scaling factor. Generating sines and cosines is not so hard to do with op amps, but making an adjustable oscillator that reliably churns out matching sine and cosine waves over a large frequency range turned out to be tricky. After a bit of experimentation, [Craig] discovered that a phase-shift oscillator was the right topology, not only for its adjustability but also because it generates sine, cosine and inverted sine terms that all come in handy when drawing various Spirograph shapes. Continue reading “Op Amp Contest: Generate Spirograph Shapes Using Only Op Amps And Math” →

The Most Ornate Birdbath You’ve Ever Seen

June 4, 2023 by Danie Conradie 8 Comments

When one thinks of art, a birdbath may not be the first thing that comes to mind. However, there is no denying that the La Fontaine aux Oiseaux (The Bird Fountain) is a true work of art. This automaton, created by automaton maker [François Junod] in collaboration with 20 different workshops and craftsmen, represents thousands of hours of work and boasts a complex beauty that is both visible and hidden.

Commissioned by the Van Cleef & Arpels jewelry company, this purely mechanical display piece features a pair of jewel-encrusted birds that perform a little routine around the edge of the bath every hour. All the birds’ appendages move while bird song is added with the help of a whistle and bellows. The “water” is also mechanized, with a series of metal plates moving together to create ripple effects, while a water lily opens and closes and a dragonfly flutters above the surface.

The overall effect of this ridiculously over-the-top mechanical art piece is absolutely mesmerizing. Even if the bejeweled exterior isn’t quite your style, you can still appreciate its intricate workings thanks the video after the break giving us a peek at the development.

We’ve featured some of [François]’ other work before, which is equally impressive and displays the mechanics in all it’s glory. If you want to try your hand at making automatons, 3D printing is the perfect way to get started.

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Supercon 2022: [Jorvon Moss] Gives His Robots A Soul

May 30, 2023 by Arya Voronova 6 Comments

How do you approach your robot designs? Maybe, you do it from a ‘oh, I have these cool parts’ position, or from a ‘I want to make a platform on wheels for my experiments’ perspective. In that case, consider that there’s a different side to robot building – one where you account for your robot’s influence on what other people around feel about them, and can get your creations the attention they deserve. [Jorvon ‘Odd-Jayy’ Moss]’s robots are catchy in a way that many robot designs aren’t, and they routinely go viral online. What are his secrets to success? A combination of an art background, a Bachelor of Fine Arts in illustration, and a trove of self-taught electronics skills helped him develop a standout approach to robot building.

Now, [Jorvon] has quite a few successful robot projects under his belt, and at Supercon 2022, he talks about how our robots’ looks and behaviour shapes their perception. How do your own robots look to others, and what feelings do they evoke? With [Jorvon], you will go through fundamentals of what makes a robot look lively, remarkable, catchy or creepy, and it’s his unique backgrounds that let him give you a few guidelines on what you should and should not do when building a certain kind of robot.

You’ll do good watching this video – it’s short and sweet, and shows you a different side to building robots of your dreams; plus, the robot riding around on the stage definitely makes this presentation one of a kind. No matter your robot’s technical complexity, it’s significant that it can make people go ‘wow’ when they see it. Not all robots are there to single-mindedly perform a simple task, after all – some are meant to travel around the world.

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Mat Boards Are Spendy, So DIY CNC Tool To The Rescue

May 29, 2023 by Donald Papp 22 Comments

Mats are flat pieces of paper-based material that fill the space between a frame and the art within. They perform a number of aesthetic and practical functions, and they can also be expensive to purchase. Making them by hand is an option, but it’s an exacting process. [wooddragon48] felt that a CNC solution would serve this need nicely, and began designing a DIY CNC tool to do exactly that.

One of the tricky parts about cutting mat boards is that cuts are at an angle, and there is really no tolerance for overcuts or any kind of visual blemish. CNC control would seem to offer a great solution to both the need for precisely straight cuts, as well as fine control over where cuts begin and end in a way that opens the door to complex designs that would be impractical to do by hand.

[wooddragon48]’s design has an angled cutter designed to plunge perfectly on demand, surrounded by a ring — similar to that on a router — which ensures the cutting tool is always consistently positioned with the material. It’s still in the design phase, but this is a type of tool that doesn’t yet exist so far as we can tell. The ability to CNC cut mat board, especially in complex designs, would be a huge timesaver.

Art and DIY CNC have a long history of happy intersection, as we have seen with a CNC router repurposed for string art, a CNC painting robot, and even an interactive abstract sculpture generator.

AI Image Generation Gets A Drag Interface

May 27, 2023 by Donald Papp 15 Comments

AI image generators have gained new tools and techniques for not just creating pictures, but modifying them in consistent and sensible ways, and it seems that every week brings a fascinating new development in this area. One of the latest is Drag Your GAN, presented at SIGGRAPH 2023, and it’s pretty wild.

It provides a point-dragging interface that modifies images based on their implied structure. A picture is worth a thousand words, so this short animation shows what that means. There are plenty more where that came from at the project’s site, so take a few minutes to check it out.

GAN stands for generative adversarial network, a class of machine learning that features prominently in software like image generation; the “adversarial” part comes from the concept of networks pulling results between different goalposts. Drag Your GAN has a GitHub repository where code is expected to be released in June, but in the meantime, you can read the full paper or brush up on the basics of how AI image generators work, as well as see how image generation can be significantly enhanced with an understanding of a 2D image’s implied depth.