TechyMagThings

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.

A key part of any tertiary musical education is learning about all the wonderful (and less wonderful) types of chords out there. Typically this involves a great deal of exercises involving the identification of a given chord from its component notes. But how would you do this programmatically? Well, thankfully, the developers behind the WhatChord tool are happy to explain just how it’s done.

The problem with classifying chords is that the way musicians use them and construct them can be quite varied. Names can also be applied somewhat differently depending on the musical context of a given set of notes. To suit the musical reality of real players and composers, WhatChord uses a specially-developed scoring algorithm to try and nut out what a chord is actually supposed to be.

As an example, a major chord must require a root note and a major third interval. It can optionally include a perfect fifth. However, if there is a minor third, minor seventh, or major seventh present, then you’re almost certainly not looking at a simple major chord. WhatChord takes these things into account by weighting the different tones present and seeing which chord gets the highest score. The required notes add weight, while notes that shouldn’t be there add a penalty to the score. Then there are extra penalties for ambiguous “unexplained” tones, extensions, and a few other parameters to disambiguate edge cases.

If you’d like to see how it works in practice, you can check out the WhatChord app and see how good it is for yourself. Alternatively, explore some of the other chord-focused projects we’ve featured over the years, or send your best musical projects into the tipsline.

[Thanks to baschwar for the tip!]

Engineering design makes all kinds of tradeoffs. Power trades off with torque, strength trades off with weight, and cost can trade off with quality. For designing a hydroelectric turbine, one of the main tradeoffs is hydraulic head with flow rate. Many large dams meant for bulk power generation will go with high head (or medium) designs, and for small dams with low head it’s usually not cost effective to build any generation. But if you’re really determined, you’ll want to build a low head water turbine like this one.

The build aims to use easy-to-find materials and simple tools. It uses 110mm and 160mm PVC pipe to not only siphon water up and over a dam, but to house the turbine as well. The turbine is built from a computer fan and sits inside the pipe with a shaft running through a Y-type fitting to the generator. The generator is built from a scavenged hoverboard wheel, and outputs a reported 3.3A DC at 60V for around 200 watts of power with only around 3m of head. The design allows the turbine to be placed at the point in the pipe that best suits the environment.

[OpenSourceLowTech], the creators of this project, make a compelling case that this build is cheaper than a 150W solar panel and it might even be able to produce more energy as well over certain timeframes, provided there’s a reliable source of water available and the owners of the dam don’t mind someone siphoning water over it continuously. The build video is worth a watch as well if for nothing else than the animation, which documents the build in excellent detail. Generating usable energy from hydropower doesn’t even need this big of a dam; if all you need is to charge your phone this tiny waterwheel will get the job done.

Thanks to [Keith] for the tip!

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!]

Do you want to go back to an era when Windows was… simpler? Back when things worked, before the AI and the bloat took over your hard drive and RAM space in equal measure? You might like to give Classic 7 a spin (via The Register).

From the drop, we should state that Classic 7 is not Windows 7 at all. Instead, it’s a reskin of Windows 10, specifically, the IoT Enterprise LTSC version. This is a particularly attractive version of Windows 10, as Microsoft has promised long-term support in terms of security updates until 2032. It also strips out annoying consumer-focused bloat like the Xbox gaming overlay and Cortana, and it eliminates forced feature updates that have become the norm in modern Windows installs. Combine all those niceties with the clean and simple feel of the recreated Windows 7 interface, and you have a beautiful operating system that has everything you need and nothing you don’t.

There are, of course, some hurdles to jump over; you’d need to find an appropriate license for this version of Windows and all that jazz. But if you long for the days before Microsoft so cruelly eviscerated the Start Menu and started making everything worse, you might find that Classic 7 is for you.

[Thanks to Stephen Walters for the tip!]

Will your next project be a success? Only time will tell, but if you build [gokux]’s tiny ESP32 fortune cookie, we predict that, at the very least, there won’t be any crumbs involved.

After briefly entertaining the idea of shoving an ESP32 in a standard fortune cookie, [gokux] thought better of it and came up with this instead. Once shaken, this small gadget displays a fortune on its e-paper screen. It can store over 3,000 fortunes and works entirely offline, so you’re never without an oracle.

Inside you’ll find a Seeed Xiao ESP32-S3 Plus and a matching e-paper display board. [gokux] is detecting the shakes with an MPU-6050 accelerometer, and powers everything with a small Li-Po pouch.

If you tire of the fortunes that shake out, the small buttons on the left side will get you into the other modes, which are a dice roller and a coin flipper. Again, you just shake the thing until you get what you want. Be sure to check it out in the video after the break.

Want to know how an MPU-6050 works, and what it looks like under the hood? Yeah, we thought so.