Arduino magnetic core memory shield


Magnetic core memory turns 60 years old today, and as a tribute [Ben North and Oliver Nash] have created a 32-bit magnetic core memory board for the Arduino.

Magnetic core memory was used from the 1950s through the 1970s, and provided a non-volatile means for storing data, as each magnetic core retained its orientation, even when the power was cut. While it sounds a lot like a modern hard drive, these devices were used in the same fashion as RAM is utilized today.

While the pair used surplus ferrite cores manufactured just before magnetic memory stopped being produced, they did allow themselves to use some modern components. Items such as transistors and logic gates were not available to the first magnetic core memory manufacturers, but the use of these items helped them complete the project in a reasonable amount of time.

Their final result is a magnetic memory board which can be used by any USB-enabled device and is reliable enough to withstand billions of read/write transactions.

Ask Hackaday: Earth’s Magnetic Field Shifting Rapidly, But Who Will Notice?

Just when you though it was safe to venture out, the National Oceanic and Atmospheric Administration released an unexpected update. Magnetic North is on the move — faster than expected. That’s right, we know magnetic north moves around, but now it’s happened at a surprising rate. Instead of waiting for the normal five year interval before an update on its position, NOAA have given us a fresh one a bit earlier.

There are some things that we can safely consider immutable, reliable, they’ll always be the same. You might think that direction would be one of them. North, south, east, and west, the points of the compass. But while the True North of the Earth’s rotation has remained unchanged, the same can not be said of our customary method of measuring direction.

Earth’s magnetic field is generated by a 2,000 km thick outer core of liquid iron and nickel that surrounds the planet’s solid inner core. The axis of the earth’s internal magnet shifts around the rotational axis at the whim of the currents within that liquid interior, and with it changes the readings returned by magnetic compasses worldwide.

The question that emerged at Hackaday as we digested news of the early update was this: as navigation moves inexorably towards the use of GPS and other systems that do not depend upon the Earth’s magnetic field, where is this still relevant beyond the realm of science?

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Electromagnetic 7-Segment Display Easy on the Eyes AND the Ears

We love electromagnetic displays: take the modern look of a digital readout, combine with the low-tech coil mechanism that you theoretically could create yourself, add a dash of random clacking sounds, and what’s not to like? Evidently, [Nicolas Kruse] shares our affection for these displays, because he’s taken it beyond theory and created a 7-segment magnetically-actuated display from scratch.

The display is 3D-printed, as you would expect these days. Each segment contains a small neodymium magnet, and each coil a 1 mm iron core for flux concentration. The coils are driven with a 1.6 A peak current, causing the segments to flip in less than 10 ms. [Nicolas] provides STL files for the display base, segments, and spools so you can print your own display. He’s also released the schematics and code for the driver, which uses an ATtiny44 to drive the coils through N- and P-channel MOSFETs. Initially designed to drive a passive 4×7 matrix of displays, the driver couldn’t quite manage to flip one segment without affecting its neighbors. However, for a single display, the driver works fine. We hope he figures out the matrix issue soon, because we really want to see a clock made with these displays.

You can see (and hear) a short video of the display in action after the break. The clacking does not disappoint!

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Electromagnetic Field 2018: Event Review

This summer’s Electromagnetic Field hacker camp in a field in western England gave many of the European side of our community their big fix of cool stuff for the year.

Some lucky individuals can spend the year as perpetual travelers, landing in a new country every week or so for the latest in the global round of camps. For the rest of us it is likely that there will be one main event each year that is the highlight, your annual fill of all that our global community has to offer. For many Europeans the main event was the biennial British event, Electromagnetic Field. From a modest start in 2012 this has rapidly become a major spectacle, one of the ones to include in your calendar, delivered both for our community and by our community.

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Core Memory Upgrade for Arduino

Linux programs, when they misbehave, produce core dumps. The reason they have that name is that magnetic core memory was the primary storage for computers back in the old days and many of us still refer to a computer’s main memory as “core.” If you ever wanted to have a computer with real core memory you can get a board that plugs into an Arduino and provides it with a 32-bit core storage. Of course, the Arduino can’t directly run programs out of the memory and as designer [Jussi Kilpeläinen] mentions, it is “hilariously impractical.” The board has been around a little while, but a recent video shined a spotlight on this retro design.

Impractical or not, there’s something charming about having real magnetic core memory on a modern CPU. The core plane isn’t as dense as the old commercial offerings that could fit 32 kilobits (not bytes) into only a cubic foot. We’ll leave the math about how much your 8-gigabyte laptop would have to grow to use core memory to you.

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Cheap and Easy Magnetic DNA Separation Method Needs Your Help

When you consider that almost every single cell in your body has more than a meter of DNA coiled up inside its nucleus, it seems like it should be pretty easy to get some to study. But with all the other cellular gunk in a crude preparation, DNA can be quite hard to isolate. That’s where this cheap and easy magnetic DNA separation method comes in. If it can be optimized and tested with some help from the citizen science community.

Commercial DNA separation methods generally involve mixing silica beads into crude cell fractions; the DNA preferentially binds to the silica, making it possible to mechanically separate it from the rest of the cellular junk. But rather than using a centrifuge to isolate the DNA, [Justin] from The Thought Emporium figured that magnets might do a better job. It’s not a new idea — biotech companies offer magnetic separation beads commercially, but at too steep a price for [Justin]’s budget. His hack comes from making magnetite particles from common iron compounds like PCB etchant and moss killer, and household ammonia cleaner. The magnetite particles are then coated with sodium silicate solution, also known as waterglass. The silica coating should allow the beads to bind to DNA, with the magnetic core taking care of separation.

[Justin] was in the process of testing his method when he lost access to the needed instruments, so he’s appealing to the larger science community for help optimizing his technique. Based on his track record of success in fields ranging from satellite tracking to graphene production, we’ll bet he’ll nail this one too.

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Sexiest Tiny Metal Core-XY 3D Printer

That’s a lot of qualifications, but we’re pretty sure that you can’t accuse us of hyperbole in the title: this is one of the tightest little 3D printer builds we’ve ever seen. Add in the slightly esoteric CoreXY kinematics and the thick aluminum frame, and it’s a speed demon in addition to being a looker.

[René] had built a few 3D printers before, so he had a good feel for the parameters and design tradeoffs before he embarked on the DICE project. Making a small print volume, for instance, means that the frame can be smaller and thus exponentially more rigid. This means that it’s capable of very fast movements — 833 mm/s is no joke! It also looks to make very precise little prints. What could make it even more awesome? Water-cooled stepper motors, magnetic interchangeable printheads, and in-built lighting.

The build looks amazing, and there is video documentation of the whole thing on [René]’s site, including a full bill of materials and designs. It’s certainly not the cheapest 3D printer we’ve ever seen, and the tiny build platform makes it a bad choice for a general-purpose machine, but if you need a second printer and you want one with style, the DICE looks hard to beat.

Thanks [Laimonus Mockus] for the tip!