Author: Al Williams

4349 Articles

Polymer Networks Make Better 3D Prints

October 17, 2020 by 5 Comments

Biological machines such as human and animal bodies are quite incredible. Your body seamlessly incorporates materials as different as muscle, bone, and tendons into an integrated whole. Now Texas A&M researchers think they can imitate nature using polymer networks that have a tunable stiffness. As a bonus, similar to biological devices, the material spontaneously self-heals.

The trick relies on the Diels-Alder reaction which is a cycloaddition reaction of a conjugated diene to an alkene. Diels-Alder-based polymers or DAPs will bond together even when they have different physical characteristics and they undergo a reversible reaction to heat which offers shape-memory and healing capability.

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Low-Level Academy Gets Into Details

October 16, 2020 by 7 Comments

We often say that you don’t have to know how an engine works to drive a car, but you can bet that every driver at the Indy 500 knows exactly how it works. You could say the same for computers. You don’t need to understand the details, but it really helps, especially if something goes wrong. [Low-Level Academy] has an online class where you can program in Rust inside your browser to learn about low-level TCP and UDP networking details.

Just how low it goes, we aren’t exactly sure, yet. There are three of eight modules ready to go. The first three cover number encoding, exchanging messages with UDP, and fragmentation. Reliability, routing, server programming, TCP, and HTTP are not out yet, but the ultimate project is a web server. In addition, new modules are released to sponsors first, so the fragmentation module for example won’t be available for a few more days. While that seems unorthodox, it is no different than having to wait for an HBO show to show up on basic cable in reruns.

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Room Temperature Superconductor? Yes, But Not So Fast…

October 15, 2020 by 24 Comments

There’s good news and there’s bad news in what we’re about to tell you. The good news is that a team of physicists has found a blend of hydrogen, carbon, and sulfur that exhibit superconductivity at 59F. Exciting, right? The bad news is that it only works when being crushed between two diamonds at pressures approaching that of the Earth’s core. For perspective, the bottom of the Marianas trench is about 1,000 atmospheres, while the superconductor needs 2.6 million atmospheres of pressure.

Granted, 59F is a bit chilly, but it is easy to imagine cooling something down that much if you could harness superconductivity. We cool off CPUs all the time. However, unless there’s a breakthrough that allows the material to operate under at least reasonable pressures, this isn’t going to change much outside of a laboratory.

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Grab A Stanford Computer Science Education

October 14, 2020 by 18 Comments

There are two reasons to go to school: learn about something and to get a coveted piece of paper that helps you get jobs, or at least, job interviews. With so many schools putting material online, you can do the first part without spending much money as long as you don’t expect the school to help you or grant you that piece of paper. Stanford has a huge computer science department and [Rui Ma] cataloged over 150 computer science classes available online in some form from the University. Just the thing to while away time during the quarantine.

Apparently, [Rui] grabbed the 2020 course catalog to find on-campus classes and found the companion website for each class, organizing them for our benefit. The list doesn’t include the actual online class offerings, which you can find directly from Stanford, although there is another list for that.

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Linux Fu: Global Search And Replace With Ripgrep

October 14, 2020 by 9 Comments

If you are even a casual Linux user, you probably know how to use grep. Even if you aren’t a regular expression guru, it is easy to use grep to search for lines in a file that match anything from simple strings to complex patterns. Of course, grep is fine for looking, but what if you want to find things and change them. Maybe you want to change each instance of “HackADay” to “Hackaday,” for example. You might use sed, but it is somewhat hard to use. You could use awk, but as a general-purpose language, it seems a bit of overkill for such a simple and common task. That’s the idea behind ripgrep which actually has the command name rg. Using rg, you can do things that grep can do using more modern regular expressions and also do replacements.

A Note on Installing Ripgrep

Your best bet is to get ripgrep from your repositories. When I tried running KDE Neon, it helpfully told me that I could install a version using apt or take a Snap version that was newer. I usually hate installing a snap, but I did anyway. It informed me that I had to add –classic to the install line because ripgrep could affect files outside the Snap sandbox. Since the whole purpose of the program is to change files, I didn’t think that was too surprising, so I did the install.

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Browser Makes Tiny Office Suite

October 13, 2020 by 17 Comments

There’s a recent craze of people living in tiny houses of 400 square feet down to as little as 80 square feet. Maybe [zserge] was thinking about that and created a very tiny office suite in which each tool weighs in at less than 1K. If you are guessing you couldn’t squeeze much functionality in C or C++ code or even assembly, you’d be right. The language of choice? HTML and JavaScript. So while the code is small, it relies on a pretty big piece of software. On the other hand, you have a browser open right now, so the incremental cost of using these tools is very small.

We get the idea that there’s not much chance this is going to sweep the shelves of Microsoft Office, Libre Office, and all the many competitors. However, it is a pretty stunning example of what you can do with modern HTML. There’s even a GitHub repo and a subreddit.

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The Cable Modem To SDR Transformation

October 10, 2020 by 5 Comments

What do you do with an old cable modem in a closet? If you are [stdw] you reverse engineer it and turn it into a software-defined radio. The modem in question was a Motorola MB7220. After looking at a similar project using a different modem, it seemed like it should be doable.

Cracking open the case revealed two likely UART ports, one of which was active. The output from that UART provided a lot of info. The chip was a Broadcom BCM3383 which is a MIPS processor. It had eCos as an operating system. However, the bootloader eventually disables the UART, so there wasn’t much more investigation possible via the serial terminal.

The next step was to dump the flash memory. That required a little solder surgery to prevent the board from starting while the flash chip had power. It appeared that some key credentials and configuration data were present, but they were really backups. After doing a factory reset to remove the backups, the right data was apparent.

After some lengthy exploration, the diagnostic that builds a spectrum display gave up its data. At first, the data was just a small sample of what was really required, but it did show a local FM station as a spectrum. Eventually, the data loss rate was down to about 12% when streaming which is not great, but good enough. You can hear an audio clip of the reception. Not exactly crystal-clear quality, but not bad.

Of course, no one will use this for an FM radio. But it is a fascinating view into how far you can hack into a device like this if you have some skills and patience. There must be something about quarantine that is making people hack old gear, as we just recently saw a similar Netgear hack. Even cheap games aren’t safe.