Always Have A Square to Spare

Some aspects of humanity affect all of us at some point in our lives. Whether it’s getting caught in the rain without an umbrella, getting a flat tire on the way to work, or upgrading a Linux package which somehow breaks the entire installation, some experiences are truly universal. Among these is pulling a few squares of toilet paper off the roll, only to have the entire roll unravel with an overly aggressive pull. It’s possible to employ a little technology so that none of us have to go through this hassle again, though.

[William Holden] and [Eric Strebel] have decided to tackle this problem with an innovative bearing of sorts that replaces a typical toilet paper holder. Embedded in the mechanism is a set of magnetic discs which provide a higher resistance than a normal roll holder would. Slowly pulling out squares of paper is possible, but like a non-Newtonian fluid becomes solid when a higher force is applied, the magnets will provide enough resistance when a higher speed tug is performed on the toilet paper. This causes the paper to tear rather than unspool the whole roll, and also allows the user to operate the toilet paper one-handed.

This is a great solution to a problem we’ve all faced but probably forgot about a minute after we experienced it. And, it also holds your cell phone to keep it from falling in the toilet! If you’d like to check out their Kickstarter, they are trying to raise money to bring the product to market. And, if you want to upgrade your toilet paper dispenser even further, there’s also an IoT device for it as well, of course.

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A Compiler in Plain Text Also Plays Music

As a layperson reading about some branches of mathematics, it often seems like mathematicians are just people who really like to create and solve puzzles. And, knowing that computer science shares a lot of its fundamentals with mathematics, we can assume that most computer scientists are also puzzle-solvers as well. This latest project from [tom7] shows off his puzzle creating and solving skills with a readable file which is also a paper, which is also a compiler for C programs, which can also play music.

[tom7] started off with the instruction set for the Intel 8086 processor. Of the instructions available, he wanted to use only instructions which are also readable in a text file. This limits him dramatically in what this file will be able to execute, but also sets up the puzzle. He walks through each of the hurdles he found by only using instructions that also code to text, including limited memory space, no obvious way of exiting the program once it was complete, not being able to jump backward in the program (i.e. looping), and a flurry of other issues that come up once the instruction set is limited in this way.

The result is a sort of C compiler which might not be the most efficient way of executing programs, but it sure is the most effective way of showing off [tom7]’s PhD in computer science. As a bonus, the file can also play an antiquated type of sound file due to one of the available instructions being a call for the processor to interact with I/O. If you want to learn a little bit more about compilers, you can check out a primer we have for investigating some of their features.

Thanks to [Greg] for the tip!

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The Embroidered Computer

By now we’ve all seen ways to manufacture your own PCBs. There are board shops who will do small orders for one-off projects, or you can try something like the toner transfer method if you want to get really adventurous. One thing we haven’t seen is a circuit board that’s stitched together, but that’s exactly what a group of people at a Vienna arts exhibition have done.

The circuit is stitched together on a sheet of fabric using traditional gold embroidery methods for the threads, which function as the circuit’s wires. The relays are made out of magnetic beads, and the entire circuit functions as a fully programmable, although relatively rudimentary, computer. Logic operations are possible, and a functional schematic of the circuit is also provided. Visitors to the expo can program the circuit and see it in operation in real-time.

While this circuit gives new meaning to the term “wearables”, it wasn’t intended to be worn although we can’t see why something like this couldn’t be made into a functional piece of clothing. The main goal was to explore some historic techniques of this type of embroidery, and explore the relationship we have with the technology that’s all around us. To that end, there have been plenty of other pieces of functional technology used as art recently as well, but of course this isn’t the first textile computing element to grace these pages.

Thanks to [Thinkerer] for the tip!

 

Do Other Things Besides Output Video

Small microcontrollers and tiny systems-on-chips are getting more and more popular these days as the price comes down and the ease of programming goes up. A Raspberry Pi is relatively inexpensive and can do pretty much everything you need, but not every chip out there can do something most of us take for granted like output video. For a lot of platforms, it’s next to impossible to do while saving any processor or memory for other tasks besides the video output itself.

[Dave] aka [Mubes] has been working on the Blue Pill platform which is a STM32F103C8 board. While they don’t natively output video, it’s a feature that provides a handy tool to have for debugging in order to see what’s going on in your code. However, if the video code takes up all of the processor power and memory there’s not much point. [Dave]’s video output program, on the other hand, takes up only 1200 bytes of RAM and 24% of the processor for a 50×18 text display over VGA, leaving a lot of room left for whatever else you need the tiny board to do.

Video output on a device this small and lightweight is an impressive feat, especially while saving room for other tasks. This brings it firmly out of the realm of novelty and into the space of useful tools to keep around. If you want to try the same thing on an ATtiny, though, you might have to come up with some more impressive tricks.

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Listening To Mains Power, Part 2

The electricity on the power grid wherever you live in the world will now universally come to you as AC. That is to say that it will oscillate between positive and negative polarity many times every second. The frequency of 50 or 60Hz just happens to be within the frequency range for human hearing. There’s a lot more than this fundamental frequency in the spectrum on the power lines though, and to hear those additional frequencies better you’ll have to do a little bit of signal processing.

We first featured this build back when it was still in its prototyping phase, but since then it’s been completed and used successfully to find a number of anomalies on the local power grid. It takes inputs from the line, isolates them, and feeds them into MATLAB via a sound card where they can be analyzed for frequency content. It’s been completed, including a case, and there are now waterfall diagrams of “mystery” switching harmonics found with the device, plus plots of waveform variation over time. There’s also a video below that has these harmonics converted to audio so you can hear the electricity.

Since we featured it last, [David] also took some feedback from the comments on the first article and improved isolation distances on his PCB, as well as making further PCB enhancements before making the final version. If you’ve ever been curious as to what you might find on the power lines, be sure to take a look at the updates on the project’s page.

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The Coco-Nutcracker

Coconut is a delicious and versatile food but if you’ve ever tried to open one you know they can be a hard nut to crack. Those of us who live in the tropics where they are common might reach for a machete, drill, or saw to open them, which is often a messy and sometimes dangerous ordeal. Realizing that a coconut is just a large nut with a shell like any other, [Paul] of [Jackman Works] decided to build a nutcracker big enough to crack a coconut, which turns out to be almost exactly human-sized.

The nutcracker is built almost entirely out of reclaimed wood. Several rings made of many blocks of wood were constructed on the table saw before being glued and clamped together. Once the rings were stacked and glued to each other, [Paul] put them on a lathe to get a smooth finish. Then the arms, legs, body, and head were all assembled. The actual nutcracking mechanism is one of the few metal parts in this build, a long threaded rod which is needed to handle the large forces required for cracking the coconut.

Once the finishing touches were put on the nutcracker, including boots, a beard, some hair, and of course a pom-pom for his hat, [Paul] successfully tested it by cracking a coconut open. This build is exceptionally high quality and is definitely worth scrolling through. He runs a wood shop in DC where he builds all sorts of interesting things like this, including a giant wooden utility knife.

Adaptive Spoon Helps Those With Parkinson’s

There are a lot of side effects of living with medical conditions, and not all of them are obvious. For Parkinson’s disease, one of the conditions is a constant hand tremor. This can obviously lead to frustration with anything that involves fine motor skills, but also includes eating, which can be even more troublesome than other day-to-day tasks. There are some products available that help with the tremors, but at such a high price [Rupin] decided to build a tremor-compensating utensil with off the shelf components instead.

The main source of inspiration for this project was the Liftware Steady, but at around $200 this can be out of reach for a lot of people. The core of this assistive spoon has a bill of material that most of us will have lying around already, in order to keep costs down. It’s built around an Arduino and an MPU6050 inertial measurement unit with two generic servo motors. It did take some 3D printing and a lot of math to get the utensil to behave properly, but the code is available on the project site for anyone who wants to take a look.

This project tackles a problem that we see all the time: a cost-effective, open-source solution to a medical issue where the only alternatives are much more expensive. Usually this comes up around prosthetics, but can also help out by making biological compounds like insulin directly for less than a medical company can provide it.

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