Hackaday Links: October 6, 2024

October 6, 2024 by Dan Maloney 22 Comments

Remember that time a giant cylindrical aquarium in a Berlin hotel bar catastrophically failed and left thousands of fish homeless? We sure do, and further recall that at the time, we were very curious about the engineering details of how this structure failed so spectacularly. At the time, we were sure there’d be plenty of follow-up on that score, but life happened and we forgot all about the story. Luckily, a faithful reader named Craig didn’t, and he helpfully ran down a few follow-up articles that came out last year that are worth looking at.

The first is from prosecutors in Berlin with a report offering three possibilities: that the adhesive holding together the acrylic panels of the aquarium failed; that the base of the tank was dented during recent refurbishment; or that the aquarium was refilled too soon after the repairs, leading to the acrylic panels drying out. We’re a little confused by that last one just from an intuitive standpoint, but each of these possibilities seems hand-wavy enough that the report’s executive summary could have been “Meh, Scheiße happens.”

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Hackaday Links: December 18, 2022

December 18, 2022 by Dan Maloney 27 Comments

By now everyone has probably seen the devastation wrought by the structural failure of what was once the world’s largest free-standing cylindrical aquarium. The scale of the tank, which until about 5:50 AM Berlin time on Friday graced the lobby of the Raddison Blu hotel, was amazing — 16 meters tall, 12 meters in diameter, holding a million liters of saltwater and some 1,500 tropical fish. The tank sat atop a bar in the hotel lobby and was so big that it even had an elevator passing up through the middle of it.

But for some reason, the tank failed catastrophically, emptying its contents into the hotel lobby and spilling the hapless fish out into the freezing streets of Berlin. No humans were killed by the flood, which is miraculous when you consider the forces that were unleashed here. Given the level of destruction, the displaced hotel guests, and the fact that a €13 million structure just up and failed, we’re pretty sure there will be a thorough analysis of the incident. We’re pretty interested in why structures fail, so we’ll be looking forward to finding out the story here.

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Aquarium Plotter Shows Sisyphish’s Submerged Sand Stripes

June 6, 2021 by Brian McEvoy 16 Comments

Sisyphus is cursed to roll a boulder up a hill for eternity. Pet fish generally content themselves to swimming the same lap over and over in a glass tank. Perpetuity can be soothing, so long as you’re not shouldering a boulder.

[Zach Frew] wants to integrate and automate the boulder on a smaller scale and one that can benefit his aquarium full of colorful Taiwanese bee shrimp. Instead of an inert rock and a Greek, Sisyphish uses a magnet and servo motors connected to a microcontroller to draw Spirograph-style shapes in the tank’s sand.

There are a couple of gears beneath the tank to trace the geometric patterns but they’re clear of any water. One gear rotates about the center of the cylindrical tank while the other holds a magnet and adjusts the distance from the center. Pilots, and select nerds, will recognize this as rho-theta positioning. Despite the uncommon coordinate system, the circular plotter accepts G-code. We love when math gets turned into gorgeous designs, and shrimp love when those tasty microbes get shaken from their gravelly hiding places.

We adore the dry sand plotters that came before, and Sisyphus himself appeared in a LEGO format that made us question our proficiency with the blocks.

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Generating Random Numbers With A Fish Tank

December 9, 2019 by Tom Nardi 27 Comments

While working towards his Computing and Information Systems degree at the University of London, [Jason Fenech] submitted an interesting proposal for generating random numbers using nothing more exotic than an aquarium and a sufficiently high resolution camera. Not only does his BubbleRNG make a rather relaxing sound while in operation, but according to tools such as ENT, NIST-STS, and DieHard, appears to be a source of true randomness.

If you want to build your own BubbleRNG, all you need is a tank of water and some air pumps to generate the bubbles. A webcam looking down on the surface of the water captures the chaos that ensues when the columns of bubbles generated by each pump collide. In the video after the break [Jason] uses two pumps, but considering they’re cheaper than lava lamps, we’d probably chuck a few more into the mix. To be on the safe side, he mentions that the placement and number of pumps should be arbitrary and not repeated on subsequent installations.

To turn this tiny maelstrom into a source of random numbers, OpenCV is first used to identify the bubbles in the video stream that are between a user-supplied minimum and maximum radius. The software then captures the X and Y coordinates of each bubble, and the resulting values are shuffled around and XOR’d until a stream of random numbers comes out the other end. What you do with this cheap source of infinite improbability is, of course, up to you.

While this project has been floating around (no pun intended) the Internet for a few years now, it seems to have gone largely overlooked, and was only just brought to our attention thanks to a tip from one of our illustrious readers. An excellent reminder that if you see something interesting out there, we’d love to hear about it.

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Aquarium Controller Starring Arduino Gets A Long Video Description

July 1, 2018 by Al Williams 4 Comments

There’s an old saying that the cobbler’s children have no shoes. Sometimes we feel that way because we stay busy designing things for other people or for demos that we don’t have time to just build something we want. [Blue Blade Fish] wanted to build an Arduino-based aquarium controller. He’s detailed the system in (so far) 14 videos and it looks solid.

This isn’t just a simple controller, either. It is a modular design with an Arduino Mega and a lot of I/O for a serious fish tank. There are controls for heaters, fans, lights, wave makers and even top-off valves. The system can simulate moonlight at night and has an LCD display and keys. There’s also an Ethernet port and a Raspberry Pi component that creates a web interface, data storage, and configures the system. Even fail safes have been designed into the system, so you don’t boil or freeze expensive fishes. No wonder it took 14 videos!

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Python Keeps A Gecko Happy: Terrarium Automation With Raspberry Pi

November 21, 2017 by Sven Gregori 8 Comments

For better or worse, pets often serve as inspiration and test subjects for hardware hacks: smarten up that hamster wheel, tweet the squirrel hunting adventures from a dog’s point of view, or automate and remote control a reptile enclosure. [TheYOSH], a gecko breeder from the Netherlands, chose the latter and wrote TerrariumPi for the Raspberry Pi to control and monitor his exotic companion’s home through a convenient web interface.

The right ecosystem is crucial to the health and happiness of any animal that isn’t native to its involuntarily chosen surroundings. Simulating temperature, humidity and lighting of its natural habitat should therefore be the number one priority for any pet owner. The more that simulation process is reliably automated, the less anyone needs to worry.

TerrariumPi supports all the common temperature/humidity sensors and relay boards you will find for the Raspberry Pi out of the box, and can utilize heating and cooling, watering and spraying, as well as lighting based on fixed time intervals or sensor feedback. It even supports location based sunrise and sunset simulation — your critter might just think it never left Madagascar, New Caledonia or Brazil. All the configuration and monitoring happens in the browser, as demonstrated in [TheYOSH]’s live system with public read access (in Dutch).

It only seems natural that Python was the language of choice for a reptile-related system. On the other hand, it doesn’t have to be strictly used for reptiles or even terrariums; TerrariumPi will take care of aquariums and any other type of vivarium equally well. After all, we have seen the Raspberry Pi handling greenhouses and automating mushroom cultivation before.

Etching A PCB In Ten Minutes.

August 15, 2016 by James Hobson 34 Comments

Most circuit boards any maker could need for their projects can be acquired online at modest cost, but what if you need something specific? [Giorgos Lazaridis] of pcbheaven.com has designed his own etching bath complete with a heater and agitator to sped up the process of creating your own custom circuit boards.

[Lazaridis] started by building a circuit to control — in a display of resourcefulness — a fish tank heater he would later modify. The circuit uses a PIC 16F526 microcontroller and two thermristors to keep the temperature of the etching bath between 38 and 41 degrees Celsius. The fish tank heater was gingerly pried from its glass housing, and its bimetallic strip thermostat removed and replaced with a wire to prevent it shutting off at its default 32 degrees. All of it is mounted on a small portable stand and once heated up, can etch a board in less than 10 minutes.

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