Automated musical instrument with LED array

ESP32 Is The Brains Behind This Art Installation

The ESP32 has enabled an uncountable number of small electronics projects and even some commercial products, thanks to its small size, low price point, and wireless capabilities. Plenty of remote sensors, lighting setups, and even home automation projects now run on this small faithful chip. But being relegated to an electronics enclosure controlling a small electrical setup isn’t all that these tiny chips can do as [Eirik Brandal] shows us with this unique piece of audio and visual art.

The project is essentially a small, automated synthesizer that has a series of arrays programmed into it that correspond to various musical scales. Any of these can be selected for the instrument to play through. The notes of the scale are shuffled through with some random variations, allowing for a completely automated musical instrument. The musical generation is entirely analog as well, created by some oscillators, amplifiers, and other filtering and effects. The ESP32 also controls a lighting sculpture that illuminates a series of LEDs as the music plays.

The art installation itself creates quite haunting, mesmerizing tunes that are illustrated in the video linked after the break. While it’s not quite to the realm of artificial intelligence since it uses pre-programmed patterns with some randomness mixed in, it does give us hints of some other projects that have used AI in order to compose new music.

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Hamster Trades Crypto Better Than You

The inner machinations of the mind of cryptocurrency markets are an enigma. Even traditional stock markets often seem to behave at random, to the point that several economists seriously suggest that various non-human animals might outperform one market or another just by random chance alone. The classic example is a monkey picking stocks at random, but in the modern world the hamster [Mr Goxx] actively trades crypto from inside his hamster cage.

[Mr Goxx]’s home comprises a normal apartment and a separate office where he can make his trades. The office contains an “intention wheel” where he can run in order to select a currency to trade, and two tunnels that [Mr Goxx] can use to declare his intention to buy or sell the currency he selected with the wheel. The wheel is connected to an Arduino Nano with an optical encoder, and the Nano also detects the hamster’s presence in the “buy” or “sell” tunnel and lights up status LEDs when he wants to execute a trade. The Nano also communicates with an intricate Java program which overlays information on the live video feed and also executes the trades in real life with real money.

Live updates are sent directly both on Twitter and Reddit, besides the live Twitch stream of [Mr Goxx] we linked above. The stream only shows his office and not his apartment, and he’s mostly active at night (Berlin time). But we can’t wait for his random walks to yield long-term results which can be analyzed for years to come. In the meantime we’ll see if others have been able to make any profits in crypto with any less-random methods.

Random Robot Makes Random Art

For the price of a toothbrush and a small motor with an offset weight, a bristlebot is essentially the cheapest robot that can be built. The motor shakes the toothbrush and the bristle pattern allows the robot to move, albeit in a completely random pattern. While this might not seem like a true robot that can interact with its environment in any meaningful way, [scanlime] shows just how versatile this robot – which appears to only move randomly – can actually be used to make art in non-random ways.

Instead of using a single bristlebot for the project, three of them are built into one 3D printed flexible case where each are offset by 120°, and which can hold a pen in the opening in the center. This allows them to have some control on the robot’s direction of movement. From there, custom software attempts to wrangle the randomness of the bristlebot to produce a given image. Of course, as a bristlebot it is easily subjected to the whims of its external environment such as the leveling of the table and even the small force exerted by the power/communications tether.

With some iterations of the design such as modifying the arms and control systems, she has an interesting art-producing robot that is fairly reliable for its inherently random movements. For those who want to give something like this a try, the code for running the robot and CAD files for 3D printing the parts are all available on the project’s GitHub page. If you’re looking for other bristlebot-style robots that do more than wander around a desktop, be sure to take a look at this line-following bristlebot too.

Thanks to [johnowhitaker] for the tip!

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This Classy But Chaotic Gear Clock Keeps You Guessing

There are a lot of ways to tell time, but pretty much all of them involve some sort of sequential scale — the hands sweeping across the face of an analog clock comes to mind, as does the incremental changes of a digital clock. Clocks are predictable by their very nature, and therefore somewhat boring.

This nonsequential gear clock aims to break that predictability and make for a timepiece that’s just a little bit different. It’s the work of [Tony Goacher], who clearly put a lot of work into it and pulled out nearly every tool in the shop while doing it. He started with a laser-cut plywood prototype to get the basics worked out — a pair of nested rings with internal gear teeth, each hanging on a stepper-driven pinion. The inner ring represents hours and the outer minutes, with the numbers on each randomly distributed — more or less, since no two sequential numbers are positioned more than five seconds of rotation apart.

The finished version of the clock is rendered in brass, acrylic, hardwood, and a smattering of aluminum, with a case reminiscent of the cathedral radios of yore. There are some really nice touches, like custom-made brass screws, a CNC-engraved brass faceplate with traditional clock art, and a Latin inscription on the drive cog for the hours ring that translates roughly to “Time rules all.” When we looked that up we found that “tempus rerum imperator” is the motto of the Worshipful Company of Clockmakers, the very existence of which we find pleasing in the extreme.

The clock runs through its initialization routine in the brief video below. We’re not sure we’d want this on our nightstand, but it’s certainly a unique and enjoyable way to show the passage of time. It sort of reminds us of this three-ringed perpetual calendar, but just a bit more stochastic.

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Chaotic Oscillator From Antique Logic

While working on recreating an “ancient” (read: 60-year-old) logic circuit type known as resistor-transistor logic, [Tim] stumbled across a circuit with an unexpected oscillation. The oscillation appeared to be random and had a wide range of frequency values. Not one to miss out on a serendipitous moment, he realized that the circuit he built could be used as a chaotic oscillator.

Chaotic systems can be used for, among other things, random number generation, so making sure that they do not repeat in a reliable way is a valuable property of a circuit. [Tim]’s design uses LEDs in series with the base of each of three transistors, with the output of each transistor feeding into the input of the next transistor in line, forming a ring. At certain voltages close to the switching voltages of the transistors, the behavior of the circuit changes unpredictably both in magnitude and frequency.

Building real-life systems that exhibit true randomness or chaotic behavior are surprisingly rare, and even things which seem random are often not random enough for certain applications. [Tim]’s design benefits from being relatively simple and inexpensive for how chaotic it behaves, and if you want to see his detailed analysis of the circuit be sure to visit his project’s page.

If you want to get your chaos the old fashioned way, with a Chua circuit, look out for counterfeit multipliers.

A 4-bit Random Number Generator

Randomness is a pursuit in a similar vein to metrology or time and frequency, in that inordinate quantities of effort can be expended in pursuit of its purest form. The Holy Grail is a source of completely unpredictable randomness, and the search for entropy so pure has taken experimenters into the sampling of lava lamps, noise sources, unpredictable timings of user actions in computer systems, and even into sampling radioactive decay. It’s a field that need not be expensive or difficult to work in, as [Henk Mulder] shows us with his 4-bit analogue random number generator.

One of the simplest circuits for generating random analogue noise involves a reverse biased diode in either Zener or avalanche breakdown, and it is a variation on this that he’s using. A reverse biased emitter junction of a transistor produces noise which is amplified by another transistor and then converted to a digital on-off stream of ones and zeroes by a third. Instead of a shift register to create his four bits he’s using four identical circuits, with no clock their outputs randomly change state at will.

A large part of his post is an examination of randomness and what makes a random source. He finds this source to be flawed because it has a bias towards logic one in its output, but we wonder whether the culprit might be the two-transistor circuit and its biasing rather than the noise itself. It also produces a sampling frequency of about 100 kbps, which is a little slow when sampling with he Teensy he’s using.

An understanding of random number generation is both a fascinating and important skill to have. We’ve featured so many RNGs over the years, here’s one powered by memes, and another by a fish tank.

Linux Fu: The Linux Shuffle

Computers are known to be precise and — usually — repeatable. That’s why it is so hard to get something that seems random out of them. Yet random things are great for games, encryption, and multimedia. Who wants the same order of a playlist or slide show every time?

It is very hard to get truly random numbers, but for a lot of cases, it isn’t that important. Even better, if you programming or using a scripting language, there are lots of things that you can use to get some degree of randomness that is sufficient for many purposes. Continue reading “Linux Fu: The Linux Shuffle”