Mysterious Files PH

[Kert Gartner]’s ASCII Aquarium turns a cheap yellow display (CYD) into a tiny simulated aquarium, complete with ASCII sea creatures each with their own behaviors. There’s all kinds of options and even timekeeping functionality, so the miniature water world can also pull its weight as a desk clock.

The fish and other animal movements are not a series of canned animations; each creature has its own behaviors and responses to things like feeding, which is accomplished by tapping on the screen. A hidden menu offers a wide range of configuration and display options, and there’s even an option to export screen contents as bitmaps.

Add a 3D-printed enclosure and the whole thing looks like a pretty nice weekend project. There’s even a display flip mode, just in case you have a spare 50 mm beamsplitter kicking around.

It’s a very clever use of a CYD that shows how good color and graphics can look when one designs with the hardware’s capabilities (and limitations) in mind.

The CYD is an ESP32-based development board with integrated touchscreen display, and is known for its affordable price and wide availability. This one would look great next to a CYD electric jellyfish.

PCBs are traditionally designed with traces laid out to support a circuit full of electronic components. However, they’ve become increasingly popular as a way to produce functional visual artworks. This PCB map from [Jonathan] is a great example.

The PCB was designed as a map of the California East Bay area. The roads are laid out as the top-side copper layer, while the land and roads are used for the top solder mask layer, with the flipped land and roads area making up the solder mask on the bottom side. The map data itself was cribbed from Snazzy Maps. Behind the PCB, [Jonathan] mounted a 64 x 32 RGB LED array, which can be seen glowing through from behind the material. The LEDs are controlled by an ESP32, which grabs location data from [Jonathan’s] family member’s mobile devices over MQTT, and uses it to light their positions on the map. Files are on Github for the curious.

If you’ve got a family that is open to location tracking, and the money to pay for a custom PCB, you could probably recreate this project yourself. We’ve seen some other great PCB maps before, too, like this amazing metro tracker. Video after the break.

Typically, when we think of touch screens, we think of LCDs or OLEDs with a resistive or capacitive sensing layer laid over the top. However, a team from the University of Chicago has developed an entirely different type of touch-sensitive display that uses persistence-of-vision techniques.

The project is called BloomBeacon. It consists of a pair of spinning arms to create a stable round display in mid-air. One arm is covered in LEDs, while the other is covered with capacitive pads for touch sensing purposes.  The trick behind this device is evident in the name—the device uses soft, flexible arms which are hinged and “bloom” upwards as the device spins up to speed. This makes it safe to physically interact with the spinning blades while they’re in motion to create a touch-interactive display. The device can thus display user interface elements like buttons that the viewer can interact with by reaching out and touching them directly.

Normally we’d advise not sticking your fingers in a rotating piece of machinery, but in this case, BloomBeacon was designed specifically to make this safe. Even sticking your fingers or hand right through the spinning arms won’t cause injury.

We’ve featured some other cool POV projects over the years, like this neat volumetric display. Video after the break.

If it’s summer in a warm, humid climate, bugs can be the bane of your existence. A natural solution is to place a passive bug zapper to catch bugs at night. But what if that isn’t fancy enough? [Nicolas Boichat] spices it up with a passive bug zapper that tracks its kill count.

But how exactly do you detect a bug zap? With an antenna, of course! When a bug gets caught, it arcs, creating an electromagnetic pulse. A small loop antenna on the backside of the zapper receives the signal.

It was also in part an experiment to see how good you can “vibe-EE” and, well, mixed results. Claude was able to correctly identify basic concepts of EE needed here, but was largely worthless at making schematics. After some manual circuit doodling, then building, [Nicolas] successfully got an ESP32-C6 to detect the voltage spikes.

Of course, where there’s data, there must be a dashboard. Using existing graphing libraries and a custom PCB, [Nicolas] has the ultimate bug zapping experience.

We’ve covered a similar idea in the past, namely one based on current sensing.

Most conventional analog watches have two or three hands, covering hours, minutes, and seconds (where present). [Sahko] has built a different kind of analog watch that creatively displays the time with just one. 

The build is based around a simple analog coil meter, which, at its heart, just sweeps its needle across a scale based on the voltage input to the device. A Raspberry Pi Pico is employed to drive the meter through a digital-to-analog converter. Pressing the buttons on the outside of the device tells the watch to display hours, minutes/seconds, or the current month or day of the week. With a single needle, only one parameter can be displayed at a time, but that’s just a compromise you accept for having a cool unique analog dial watch.

Another cool touch in the design is that the dial backer isn’t just a printed piece of paper—it’s a custom PCB, which has a much nicer, hardier finish. The case of the watch is also CNC milled out of aluminum and bead blasted for a quality surface finish, adding a nice industrial touch to the build.

This is a great example of a custom watch with quality fit and finish. The attention to detail really pays off in terms of feel. We’ve seen other watch projects use similar construction techniques before, too.

A healthy aquarium ecosystem requires very specific conditions, with factors like the salinity and temperature having to be just right to keep said ecosystem happy. As some species are adapted to fairly cold water, this requires the use a water chiller. Recently [The Blunt Oracle] modified one of these aquarium-focused chillers with a much better controller to make it both more accurate and potentially more efficient as well.

The target for the surgery was a generic Shanhuchong Y-160 chiller that after a brief teardown turned out to use an STC-1000 style controller. The biggest disadvantage with this unit is probably that it just has one temperature probe, which monitored the temperature of the heat exchanger rather than that of the chilled water tank.

This controller was replaced with a Wi-Fi-equipped Elitech ECS-974T sourced for $50 off AliExpress that uses the same 71 x 29 mm form factor. Following that it was just a matter of some creative rewiring – as shown in the top image – and installing the twin temperature probes of the new controller.

Being able to monitor also the temperature of the chilled water adds a layer of redundancy that’s very welcome after splurging thousands of clams on a fancy aquarium and its inhabitants. As a bonus the Wi-Fi interface allows for it to be monitored and controlled remotely, with [The Blunt Oracle] pushing the Home Assistant configuration in a PR as well that recently got merged. They’d also like to extend their thanks to Elitech for having pretty good documentation that really helped with creating the HA configuration file, which is a rarity with many of such controllers.

If you just want to play with a Rubik’s Cube, you can simply buy one from a local toy store. If you want to build one, you could 3D print something and put it together yourself. But what if you want to make lots of Rubik’s Cubes? Then, you might go down the road that [EngBroken] just walked.

What started as a fun reverse-engineering project would lead to an 8-month journey to reproduce Rubik’s Cubes from scratch using injection molding. [EngBroken] started by identifying the basic pieces that make up the cheap cube they bought, including the center core, the edge pieces, and the corner pieces. Parts were then recreated in CAD, and [EngBroken] then set about designing and milling injection molds out of 6061 aluminium to make the parts.

Amusingly, to get the correct colors for the separate parts of the cube, [EngBroken] made the curious decision to mix cut-up pieces of 3D printer filament with clear ABS pellets to tint it as needed. Parts were then assembled with UV-curing glue, and [EngBroken] had a Rubik’s cube built from scratch. Well he actually had several, since he had a stack of parts since injection molding is great at producing things in quantity.

This isn’t a great way to go if you want a Rubik’s cube on the cheap. [EngBroken] estimates the labor put in to this exercise came out to $56,000 alone, to say nothing of what it took to produce all those aluminium molds and source all that plastic. Still, a great deal was learned in the process. We’ve looked at the challenges of injection molding before, too.

[Thanks to Sailor Looking Meme for the tip!]