Ask any electronics hobbyist or professional what the simplest building blocks of electronic circuits are, and they’ll undoubtedly say resistors, capacitors, and inductors. Ask a mechanically-inclined person the same question about their field and the answer will probably be less straightforward. Springs would make the list for sure, but then… hmm. Maybe gears? 80/20 aluminum extrusions?
As it turns out, there are a handful of fundamental building blocks in the mechanisms world, and they’re functionally very similar, and mathematically identical, to the Big Three found in electrical engineering.
Mechanical Equivalents
Before we look at the components themselves, let’s step back a moment and think about voltage and current. Voltage is a potential difference between two points in a circuit, sometimes called electromotive force (EMF). It turns out that EMF is an apt term for it, because it is roughly analogous to, well, force. Voltage describes how “hard” electrons are being “pushed” in a circuit. In much the same vein, current describes the rate of electric charge flow. Continue reading “Building Blocks: Relating Mechanical Elements To Electronic Components”→
People are obsessed with the time and the weather. We’ve talked about the weather since we were all cave dwellers hunting with spears. But the time is a different matter. Sure, people always had the idea of the passage of time. The sun rising and setting gives a natural sense of days, but daylight and dark periods vary by the time of year and to get an accurate and linear representation of time turns out to be rather difficult. That is unless you are a Greek engineer living in Alexandria around 250 BC.
Legend has it that and engineer working in his father’s barbershop led him to discover not only the first working clock, but also the pipe organ, launching the field of pneumatics in the process. That engineer was named Ctesibius and while his story is mostly forgotten, it shows he has a place as a historical hacker.
You might think there were timekeeping devices before 250 BC, and that’s sort of true. However, the devices before Ctesibius had many limitations. For example, a sundial can tell time, but only if the sun is shining. At night or during a storm it is worthless.
The International Space Station is humanity’s most expensive gym membership.
Since the earliest days of human spaceflight, it’s been understood that longer trips away from Earth’s gravity can have a detrimental effect on an astronaut’s body. Floating weightless invariably leads to significantly reduced muscle mass in the same way that a patient’s muscles can atrophy if they spend too much time laying in bed. With no gravity to constantly fight against, an astronauts legs, back, and neck muscles will weaken from disuse in as little as a week. While this may not pose an immediate problem during spaceflight, astronauts landing back on Earth in this physically diminished state are at a higher risk of injury.
Luckily this problem can be largely mitigated with rigorous exercise, and any orbiting vessel spacious enough to hold human occupants for weeks or months will by necessity have enough internal volume to outfit it with basic exercise equipment such as a treadmill or a resistance machine. In practice, every space station since the Soviet Union’s Salyut 1 in 1971 has featured some way for its occupants to workout while in orbit. It’s no replacement for being on Earth, as astronauts still return home weaker than when they left, but it’s proven to be the most practical approach to combating the debilitating aspects of long duration spaceflight.
Early NASA concept for creating artificial gravity.
Of course, there’s an obvious problem with this: every hour spent exercising in space is an hour that could be better spent doing research or performing maintenance on the spacecraft. Given the incredible cost of not just putting a human into orbit, but keeping them there long-term, time is very literally money. Which brings us back to my original point: astronauts spending two or more hours each day on the International Space Station’s various pieces of exercise equipment just to stave off muscle loss make it the world’s most expensive gym membership.
The ideal solution, it’s been argued, is to design future spacecraft with the ability to impart some degree of artificial gravity on its passengers through centripetal force. The technique is simple enough: just rotate the craft along its axis and the crew will “stick” to the inside of the hull. Unfortunately, simulating Earth-like gravity in this way would require the vessel to either be far larger than anything humanity has ever launched into space, or rotate at a dangerously high speed. That’s a lot of risk to take on for what’s ultimately just a theory.
But a recent paper from the University of Tsukuba in Japan may represent the first real steps towards the development of practical artificial gravity systems aboard crewed spacecraft. While their study focused on mice rather than humans, the results should go a long way to codifying what until now was largely the stuff of science fiction.
As nation states grapple with the spectre of environmental and economic losses due to climate change, we’ve seen an ever greater push towards renewable energy sources to replace heavier polluters like coal and natural gas. One key drawback of these sources has always been their intermittent availability, spurring interest in energy storage technologies that can operate at the grid level.
With the rise in distributed energy generation with options like home solar power, there’s been similar interest in the idea of distributed home battery storage. However, homeowners can be reluctant to make investments in expensive batteries that take years to pay themselves off in energy savings. But what if they had a giant battery already, just sitting outside in the driveway? Could electric vehicles become a useful source of grid power storage? As it turns out, Ford wants to make their electric trucks double as grid storage batteries for your home.
A lot of our projects make noise. It can be something as simple as a microcontroller driving a small speaker or a truly ambitious Hi-Fi project, but common to all of them is the desire to get that sound out in as audible and high-quality a manner as possible. We’ve been known to make fun of the more preposterous side of the Hi-Fi world at times, but behind it all there’s a basis of solid and provable audio engineering that can be brought to bear on almost any project involving sound and electronics. Perhaps it’s time to devote some time to a series exploring the topic, and what better place to start than the ultimate destination for all that sound. Any Hi-Fi is only as good as the ears of the person listening to it, so in out journey through the world of audio that’s where we’ll start. Continue reading “Know Audio: Start At The Very Beginning”→
For years now we have been told that self-driving cars will be the Next Big Thing, and we’ve seen some companies — yes, Tesla but others too — touting current and planned features with names like “Autopilot” and “self-driving”. Cutting through the marketing hype to unpacking what that really means is difficult. But there is a standard for describing these capabilities, assigning them as levels from zero to five.
Now we’re greeted with the news that Honda have put a small number of vehicles in the showrooms in Japan that are claimed to be the first commercially available level 3 autonomous cars. That claim is debatable as for example Audi briefly had level 3 capabilities on one of their luxury sedans despite having few places to sell it in which it could be legally used. But the Honda Legend SENSING Elite can justifiably claim to be the only car on the market to the general public with the feature at the moment. It has a battery of sensors to keep track of its driver, its position, and the road conditions surrounding it. The car boasts a “Traffic Jam Pilot” mode, which “enables the automated driving system to drive the vehicle under certain conditions, instead of the driver, such as when the vehicle is in congested traffic on an expressway“.
Sounds impressive, but just what is a level 3 autonomous car, and what are all the other levels?
When you want to read what is being said on a television program, movie, or video you turn on the captions. Looking under the hood to see how this text is delivered is a fascinating story that stared with a technology called Closed Captions, and extended into another called Subtitles (which is arguably the older technology).
I covered the difference between the two, and their backstory, in my previous article on the analog era of closed captions. Today I want to jump into another fascinating chapter of the story: what happened to closed captions as the digital age took over? From peculiar implementations on disc media to esoteric decoding hardware and a baffling quirk of HDMI, it’s a fantastic story.
There were some great questions in the comments section from last time, hopefully I have answered most of these here. Let’s start with some of the off-label uses of closed captioning and Vertical Blanking Interval (VBI) data.
