Author: Maya Posch

1887 Articles

Equipping Rats With Backpacks To Find Victims Under Rubble

February 5, 2023 by 20 Comments

When it comes to demining or finding victims after a disaster, dogs are well-known to aid humans by sniffing out threats and trapped humans with ease. Less well-known, but no less impressive are rats, with the African giant pouched rat being the star of the show. Recently a student at the Dutch Technical University of Eindhoven (TU/e) has demonstrated how these rats can sniff out buried victims, aided by a high-tech backpack that gives them a communication link back to their human handler.

All of this is done in association with the Belgian-registered and Tanzania-based NGO APOPO, whose achievements include training gold medal winner Magawa the rat, who helped find 71 landmines and dozens more types of UXO over a 5-year career. These landmine-hunting rats are known as HeroRATs and have been helping demine nations since the 1990s. They may be joined by RescueRats in the near future.

Each RescueRat is equipped with a backpack that contains a camera and battery, as well as GPS and altimeter. Each backpack includes a button that the rat is trained to press when they have found a victim — essentially dropping a pin on their human rescuer’s maps.

Figuring out the location of the victim inside the rubble pile is the real challenge. This is where a (LoRa) radio beacon in the backpack is triangulated using receivers placed around the area, allowing the rescuers to determine with reasonable accuracy where to focus their efforts.

(Thanks to [Roel] for the tip!)

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The Effect Of Filament Color On Print Strength And More

February 5, 2023 by 16 Comments

What is an FDM filament coloring’s purpose but to be an aesthetic choice? As it turns out, the additives that create these changes in coloring and transparency also affect the base properties of the polymer, whether it’s PLA, PETG, or another material. This is where a recent video by [CNC Kitchen] is rather illustrative, using a collection of colored PLA filaments from a single filament manufacturer.

[CNC Kitchen] ran a range of tests including tensile strength, ductility, layer adhesion, impact resistance, and annealing performance. The results showed no clear overall winner between plain PLA polymer and any specific color. Perhaps most fascinating was just how much these color additives change the material’s response to annealing. Baking the PLA at 100°C for 30 minutes generally improves material properties, but also can cause warping and shrinking. The effective warping and shrinking differed wildly between the filament.

The general conclusion would seem to be that the natural polymer isn’t necessarily the optimal choice, but that you should test and pick the filament from a specific manufacturer to fit your project’s needs.

Continue reading “The Effect Of Filament Color On Print Strength And More” →

Reliving A Bitmapped Past With A Veritable Hoard Of Bitmap Fonts

February 4, 2023 by 12 Comments

The fonts seen with old computer systems such as those from Apple and Commodore, as well as Microsoft Windows 3.1 and older, form an integral part of our interaction with these systems. These days such bitmap fonts are a rarity, with scalable vector-based fonts having taken their place on modern-day systems. This unfortunately also means that these fonts are at major risk of being lost to the sands of time. This is where [Rob Hagemans] seeks to maintain an archive of such bitmap fonts, ranging from Acorn to MSX to Windows.

Many of these fonts are extracted from character ROMs, with a preview of some of these fonts available via the Monobit viewer. The fonts themselves are made available in YAFF format, which is a text-based format that can be converted back to a binary format using the Monobit tool. If you ever wanted to use one of these old bitmap fonts in a project, this would seem to offer a treasure trove of options. The hoard of bitmap fonts might be the perfect fit for your next graphic LCD project.

(Via [SuperIlu] on Mastodon)

The Struggle Of Keeping A 1950s Candlepin Bowling System Working

February 3, 2023 by 45 Comments

When we hear the term ‘bowling’, most of us think of what is known as ten-pin bowling, yet this is only one of the many variations. Candlepin bowling — so called because of the distinctive pin shape — has been around since 1880, yet is mostly played within the US New England and Canadian Maritime provinces. Because of how relatively uncommon it is, candlepin bowling alleys such as the one that [Autumn Mowery]’s family runs is struggling to keep the system working, much of it due to a lack of spare parts.

On [Autumn]’s YouTube channel she goes through many of the behind the scene details at the Ellsworth, Maine-based bowling alley, the repairs and the scavenging of spare parts from the sacrificial bowling lanes that are used to keep the other lanes going for as long as possible. With the mechanics of the installed candlepin bowling system dating back to the 1940s and having been use constantly since the 1950s, it’s an every day struggle to keep the system from breaking down, with no spare parts available for sale.

Although the financially responsible approach might be to give up on the system and have a readily available tenpin bowling system installed instead, there’s a lot more to this form of bowling than the difference in pin shape. Differences include the much stricter rules, the use of a smaller ball without finger holes, lower chance of hitting a pin, and so on. This, along with the historical significance of the sport and this particular system would make it appear to be something that’s right up the (bowling) alley of our audience.

How’d you keep a 1950s-era bowling system up and running?

Thanks to [Tara Calishain] for the tip!

Comparing Cheap Capacitative Soil Moisture Sensors With Commercial Sensors

February 1, 2023 by 41 Comments

When your residence has soil moisture sensors embedded that were dictated by your friendly neighborhood HoA, you may start asking questions about the system used. That’s what [Modest Maker] did and the resulting findings along with an attempt to beat the commercial system with some cheap capacitive sensors, are covered  in a recent video that’s also embedded below. Part of the motivation here was that the commercial system in the community was not clearly installed properly.

To make a long story short, the commercial system by Hunter (Soil-Clik) appears to be a tensiometer-based system that uses the pressure produced by moisture intrusion into the measurement column. This translates to how easy it is for plant roots to extract water, depending on the soil type. [Modest Maker] had to first dodge the broken-by-design capacitive sensors that are available everywhere, but after that was able to cobble together a measurement system that he hopes will allow him to validate the commercial system’s installation.

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Detecting Machine-Generated Content: An Easier Task For Machine Or Human?

February 1, 2023 by 41 Comments

In today’s world we are surrounded by various sources of written information, information which we generally assume to have been written by other humans. Whether this is in the form of books, blogs, news articles, forum posts, feedback on a product page or the discussions on social media and in comment sections, the assumption is that the text we’re reading has been written by another person. However, over the years this assumption has become ever more likely to be false, most recently due to large language models (LLMs) such as GPT-2 and GPT-3 that can churn out plausible paragraphs on just about any topic when requested.

This raises the question of whether we are we about to reach a point where we can no longer be reasonably certain that an online comment, a news article, or even entire books and film scripts weren’t churned out by an algorithm, or perhaps even where an online chat with a new sizzling match turns out to be just you getting it on with an unfeeling collection of code that was trained and tweaked for maximum engagement with customers. (Editor’s note: no, we’re not playing that game here.)

As such machine-generated content and interactions begin to play an ever bigger role, it raises both the question of how you can detect such generated content, as well as whether it matters that the content was generated by an algorithm instead of by a human being.

Continue reading “Detecting Machine-Generated Content: An Easier Task For Machine Or Human?” →

A New Analog And CRT Neck Board For The MacIntosh SE

January 31, 2023 by 13 Comments

Keeping a 35-year old system like the MacIntosh SE and its successor, the SE/30, up and running requires the occasional replacement parts. As an all-in-one system, the analog board that provides the power for not only the system but also the 9″ (23 cm) built-in CRT is a common failure location, whether it is due to damaged traces, broken parts or worse. For this purpose [Kay Koba] designed a replacement analog board, providing it with a BOM of replacement components. This also includes the neck board, which is the part that the CRT itself connects to.

As [Kay] notes in the project log, the design was inspired after building [Kai Robinson]’s Classic Reloaded logic board, which we covered previously. After a few revisions, [Kay] has now begun selling the PCBs for $42. The product page also links to BOMs for both the analog board and the neck board, with most of the parts simple through-hole parts. If the board’s fancy styling and LEDs compared to the original board isn’t your cup of tea, it does look like there exists interest in a more subdued version as well.