We always enjoy [NileRed’s] videos. His latest shows how he made some relatively high-temperature superconducting ceramic. After finding what appeared to be some really good instructions on the Internet, [NileRed] found there were some things in the paper that didn’t make sense. You can watch the video, below.
The superconductor was YBCO, sometimes known as 123 because of the ratio of its components. Turns out that most of the materials were available online, except for one exotic chemical that he had to buy from a more conventional source.
Continue reading “[NileRed] Makes Superconductors”
Imagine that you want to output multiple lines of text in Bash, or any shell script. Maybe it’s for a help string for a particularly convoluted shell script you’re writing. You could have a separate
echo command for each line. Or you could use the “here document“.
The “here document” construction takes the text between two delimiters and passes it, as if it were piped, to a command.
if [[$# == 0 ]] || [[ "$1" == "-h" ]]; then
cat << EOF
This is my help message. There are many like it but this one is mine.
My help message is my best friend.
All of the text, as written, with line breaks and spaces and all, get passed to
cat and your helpful formatted message is printed to the user.
Continue reading “Linux-Fu: Help Messages For Shell Scripts And Here Documents”
[Donald Bell’s] robotic bartender entry into the 2020 Cocktail Robotics Grand Challenge is one of those things that sounds easy until you start getting into the details. After all, how hard is it to dispense some liquids into a glass? Harder than you might think. Sure there are pumps — [Donald] uses peristaltic pumps — but there’s also two Raspberry Pis, an ESP8622, and at least one more microcontroller lurking underneath. You can see a video about the device below.
Even if you don’t want a refreshing libation, you’ll probably like the VK-01’s Bladerunner cyberpunk styling. What we really enjoyed about the post was that it took you through the concept sketches, some of the design trades, and even a cardboard prototype.
Continue reading “VK-01 Is A Bartender You Don’t Need To Tip”
One of the best things about the Internet — especially the video part — is that you can get exposed to lots of things you might otherwise not be able to see. Take oscilloscopes, for example. If you were lucky, you might have one or two really nice instruments at work and you certainly weren’t going to be allowed to tear them open if they were working well. [The Signal Path], as a case in point, tears down a $30,000 MSO6 8 GHz oscilloscope.
Actually, the base price is not quite $30,000 but by the time you outfit one, you’ll probably break the $30K barrier. Compared to the scopes we usually get to use, these are very different. Sure, the screens are larger and denser, but looking at the circuit boards they look more like some sort of high-end computer than an oscilloscope. Of course, in a way, that’s exactly what it is.
Continue reading “Inside A $30,000 8 GHz Scope”
You might think the smell of an electrolytic capacitor boiling out is bad, but if scientists from the University of Sydney have their way, that might be nothing. They’ve devised an ultracapacitor — that uses biomass from the stinky durian fruit along with jackfruit. We assume the capacitors don’t stink in normal use, but we wouldn’t want to overload one and let the smoke out.
One of the things we found interesting about this is that the process seemed like something you might be able to reproduce in a garage. Sure, there were a few exotic steps like using a vacuum oven and a furnace with nitrogen, and you’d need some ability to handle chemicals like vinylidene fluoride. However, the hacker community has found ways to create lots of things with common tools, and we would imagine creating aerogels from some fruit ought not be out of reach.
Continue reading “Ultracapacitors Might Have Bad Fruity Smell”
There was a time when it was easy to eavesdrop on police and other service radio networks. Police scanners fans can hear live police, fire, and ambulance calls. However, it isn’t as easy as it used to be because nearly all radios now are trunked. That means conversations might jump from channel to channel. However, P25 can unscramble trunked radio calls intercepted by a cheap SDR dongle and let you listen in. [SignalsEverywhere] shows you how to set it up for Windows or Linux and you can see the video below.
Trunking radio makes sense. In the old days, you might have a dozen channels for different purposes. But most channels would be empty most of the time. With trunking radio, a radio’s computer is set to be in a talk group and a control channel sorts out what channel the talk group should use at any given time. That means that one channel might have several transmissions in a row from different talk groups and one talk group might hop to a new channel on each transmission.
Continue reading “Trunking Police Scanning With SDRTrunk”
We take wireless devices for granted these days, and it is easy to forget that the use of the airwaves is subject to government control — the FCC in the United States. HobbyKing got a sharp reminder when the FCC levied a nearly $3 million fine for the company selling uncertified drone transmitters.
It was hardly a surprise, though. The FCC has been cracking down on these noncompliant transmitters for a while now and had issued a notice of apparent liability to the company back in 2018 and the investigation goes back to 2016. The problems included radios being sold that were on unauthorized frequencies, radios with higher than legal output power, and selling radios that were not type accepted.
Continue reading “FCC Fines Hobby King Almost $3 Million For Illegal Drone Transmitters”