Day: November 9, 2020

The Logic Chip RISC-V Project Reboots

November 9, 2020 by 15 Comments

The RISC-V architecture is inexorably inching from its theoretical origins towards the mainstream, as what could once only be done on an exotic FPGA can now be seen in a few microcontrollers as well as some much more powerful processors. It’s exciting because it offers us the prospect of fully open-source hardware on which to run our open-source operating systems, but it’s more than that. RISC-V isn’t a particular processor core so much as a specification that can be implemented at any of a number of levels, and in its simplest form can even be made real using 74 logic chips. This was the aim of [Robert Baruch]’s LMARV-1 that caused a stir a year or two ago but then went on something of a hiatus. We’re pleased to note that he’s posted a video announcing a recommencement of the project, along with a significant redesign.

We’ve placed the video below the break, and it’s much more than a simple project announcement. Instead, it’s an in-depth explanation of the design decisions and the physical architecture of the processor. It amounts to a primer on processor design, and though it’s a long watch we’d say you won’t be disappointed if your interests lie in that direction.

We first covered the LMARV-1 back in early 2018, so we’re glad to see it back in progress and we look forward to seeing its continued progress.

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Product Review: The TinySA, A Shirt-Pocket Sized Spectrum Analyzer

November 9, 2020 by 39 Comments

I suppose most of us have had the experience of going to the mailbox and seeing that telltale package in the white plastic bag, the sign that something has just arrived from China. This happened to me the other day, and like many of you it was one of those times when I puzzled to myself: “I wonder what I bought this time?”

With so many weeks or months between the time of your impulsive click on the “Buy Now” button on AliExpress or eBay and the slow boat from China actually getting the package to your door, it’s easy enough to forget what exactly each package contains. And with the price of goods so low, the tendency to click and forget is all the easier. That’s not necessarily a good thing, but I like surprises as much as the next person, so I was happy to learn that I was now the owner of a tinySA spectrum analyzer. Time for a look at what this little thing can do.

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Ethernet Goes To The Ether

November 9, 2020 by 14 Comments

Since the ether is an old term for the fictitious space where radio waves propagate, we always thought it was strange that the term ethernet refers to wired communication. Sure, there are wireless devices, but that’s not really ethernet. [Jacek] had the same thought, but decided to do something about it.

What he did is use two different techniques to alter the electromagnetic emission from an ethernet adapter on a Raspberry Pi. The different conditions send Morse code that you can receive at 125 MHz with a suitable receiver.

Practical? Hardly, unless you are looking to exfiltrate data from an air-gapped machine, perhaps. But it does have a certain cool factor. The first method switches the adapter between 10 Mbps and 100 Mbps. The second technique uses a stream of data to accomplish the modulation. The switching method had a range of around 100 meters while the data-based method topped out at about 30 meters. The code is on GitHub if you want to replicate the experiment.

There is plenty of precedent for this sort of thing. In 1976 Dr. Dobb’s Journal published an article about playing music on an Altair 8800 by running code while an AM radio was nearby. We’ve seen VGA adapters forced to transmit data, too.

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From Trash PPE To New PPE

November 9, 2020 by 19 Comments

As the coronavirus pandemic circles the world, a fact of daily life for millions of people has become the wearing of a face mask. Some people sport colorful fabric masks, but for many, this means the ubiquitous Chinese disposable mask. They have become the litter of our time, which as [blorgggg] notes is something that shouldn’t have to be the case. Their plastic can be recycled and made into other useful things, for example, ear savers similar to the ones many of us were 3D printing earlier in the year.

As you might imagine diving into a pile of used masks can be a little unhygienic, so the first step is to disinfect with alcohol. Then the various layers can be separated and the outer polypropylene ones collected and stacked between baking parchment to be melted on a skillet. The result is a polypropylene sheet that can be laser cut if it is thick enough, and from this are cut the ear savers. It’s not quite as neat a cut as the acrylic sheet we may be used to, but it’s adequate for the task.

While on the subject of masks, earlier in the year we presented a series in whose first part we dissected a selection.