Circuit VR: Advanced Falstad Logic With Geniac

August 20, 2019 by Al Williams 2 Comments

I find that if I’m trying to make a point with a student or a colleague about a circuit, sometimes the Falstad online simulator is worth a few thousand words. You can draw the circuit, play with the values, and even see the current flow in an intuitive way as well as make traditional measurements. The simulator not only handles analog but also digital circuits. At first glance, though, the digital functions appear limited, but if you dig deeper, there is a custom logic block that can really help. I dug into this — and into how switches work in the simulator — the other day in response to a Hackaday post. If you use Falstad, read on!

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Echos Of The Cold War: Nuclear-Powered Missiles Have Been Tried Before

August 20, 2019 by Tom Nardi 63 Comments

On August 8th, an experimental nuclear device exploded at a military test facility in Nyonoksa, Russia. Thirty kilometers away, radiation levels in the city of Severodvinsk reportedly peaked at twenty times normal levels for the span of a few hours. Rumors began circulating about the severity of the event, and conflicting reports regarding forced evacuations of residents from nearby villages had some media outlets drawing comparisons with the Soviet Union’s handling of the Chernobyl disaster.

Today, there remain more questions than answers surrounding what happened at the Nyonoksa facility. It’s still unclear how many people were killed or injured in the explosion, or what the next steps are for the Russian government in terms of environmental cleanup at the coastal site. The exceptionally vague explanation given by state nuclear agency Rosatom saying that the explosion “occurred during the period of work related to the engineering and technical support of isotopic power sources in a liquid propulsion system”, has done little to assuage concerns.

The consensus of global intelligence agencies is that the test was likely part of Russia’s program to develop the 9M730 Burevestnik nuclear-powered cruise missile. Better known by its NATO designation SSC-X-9 Skyfall, the missile is said to offer virtually unlimited flight range and endurance. In theory the missile could remain airborne indefinitely, ready to divert to its intended target at a moment’s notice. An effectively unlimited range also means it could take whatever unpredictable or circuitous route necessary to best avoid the air defenses of the target nation. All while traveling at near-hypersonic speeds that make interception exceptionally difficult.

Such incredible claims might sound like saber rattling, or perhaps even something out of science fiction. But in reality, the basic technology for a nuclear-powered missile was developed and successfully tested nearly sixty years ago. Let’s take a look at this relic of the Cold War, and find out how Russia may be working to resolve some of the issues that lead to it being abandoned. Continue reading “Echos Of The Cold War: Nuclear-Powered Missiles Have Been Tried Before” →

Apollo’s PLSS And The Science Of Keeping Humans Alive In Space

August 19, 2019 by Maya Posch 13 Comments

Ever since humans came up with the bright idea to explore parts of the Earth which were significantly less hospitable to human life than the plains of Africa where humankind evolved, there’s been a constant pressure to better protect ourselves against the elements to keep our bodies comfortable. Those first tests of a new frontier required little more than a warm set of clothes. Over the course of millennia, challenging those frontiers became more and more difficult. In the modern age we set our sights on altitude and space, where a warm set of clothes won’t do much to protect you.

With the launch of Sputnik in 1957 and the heating up of the space race between the US and USSR, many firsts had to be accomplished with minimal time for testing and refinement. From developing 1945’s then state-of-the-art V-2 sounding rockets into something capable of launching people to the moon and beyond, to finding out what would be required to keep people alive in Earth orbit and on the Moon. Let’s take a look at what was required to make this technological marvel happen, and develop the Portable Life Support System — an essential component of those space suits that kept astronauts so comfortable they were able to crack jokes while standing on the surface of the Moon.

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Safety Systems For Stopping An Uncontrolled Drone Crash

August 15, 2019 by Jenny List 33 Comments

We spend a lot of time here at Hackaday talking about drone incidents and today we’re looking into the hazard of operating in areas where people are present. Accidents happen, and a whether it’s a catastrophic failure or just a dead battery pack, the chance of a multi-rotor aircraft crashing down onto people below is a real and persistent hazard. For amateur fliers, operating over crowds of people is simply banned, but there are cases where professionally-piloted dones are flying near crowds of people and other safety measures need to be considered.

We saw a skier narrowly missed by a falling camera drone in 2015, and a couple weeks back there was news of a postal drone trial in Switzerland being halted after a parachute system failed. When a multirotor somehow fails while in flight it represents a multi-kilogram ~~flying weapon~~ widow-maker equipped with spinning blades, how does it make it to the ground in as safe a manner as possible? Does it fall in uncontrolled flight, or does it activate a failsafe technology and retain some form of control as it descends?

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India Launched A Moon Orbiter, Lander, And Rover All In One Shot With Chandrayaan-2

August 14, 2019 by Tom Nardi 62 Comments

On July 22nd, India launched an ambitious mission to simultaneously deliver an orbiter, lander, and rover to the Moon. Launched from the Satish Dhawan Space Centre on a domestically-built GSLV Mk III rocket, Chandrayaan-2 is expected to enter lunar orbit on August 20th. If everything goes well, the mission’s lander module will touch down on September 7th.

Attempting a multifaceted mission of this nature is a bold move, but the Indian Space Research Organisation (ISRO) does have the benefit of experience. The Chandrayaan-1 mission, launched in 2008, spent nearly a year operating in lunar orbit. That mission also included the so-called Moon Impact Probe (MIP), which deliberately crashed into the surface near the Shackleton crater. The MIP wasn’t designed to survive the impact, but it still secured India a position on the short list of countries that have placed an object on the lunar surface.

If the lander component of Chandrayaan-2, named Vikram after Indian space pioneer Vikram Sarabhai, can safely touch down on the lunar surface it will be a historic accomplishment for the ISRO. To date, the only countries to perform a controlled landing on the Moon are the Soviet Union, the United States, and China. Earlier in the year, it seemed Israel would secure its position as the fourth country to perform the feat with their Beresheet spacecraft, but a last second fault caused the craft to crash into the surface. The loss of Beresheet, while unfortunate, has given India an unexpected chance to take the coveted fourth position despite Israel’s head start.

We have a few months before the big event, but so far, everything has gone according to plan for Chandrayaan-2. As we await word that the spacecraft has successfully entered orbit around the Moon, let’s take a closer look at how this ambitious mission is supposed to work.

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Cheap Electric Scooter Gets A Big Brake Upgrade; Unlocks Proper Drift Mode

August 14, 2019 by Lewin Day 7 Comments

The last few years have seen a huge rise in the prominence of electric scooters. Brushless motors, lithium batteries, and scooter sharing companies have brought them to the mainstream. However, electric scooters of a variety of designs have been around for a long time, spawning a dedicated subculture of hackers intent on getting the best out of them.

One such hacker is yours truly, having started by modifying basic kick scooters with a variety of propulsion systems way back in 2009. After growing frustrated with the limitations of creating high-speed rotating assemblies without machine tools, I turned my eye to what was commercially available. With my first engineering paycheck under my belt, I bought myself a Razor E300, and was promptly disappointed by the performance. Naturally, hacking ensued as the lead-acid batteries were jettisoned for lithium replacements.

Over the years, batteries, controllers and even the big old heavy brushed motor were replaced. The basic mechanical layout was sound, making it easy to make changes with simple hand tools. As acceleration became violent and top speeds inched closer to 40 km/h, I began to grow increasingly frustrated with the scooter’s one glaring major flaw. It was time to fix the brakes.

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Retrotechtacular: Predictions That Just Missed It

August 13, 2019 by Al Williams 40 Comments

Few occupations are more fraught with peril than predicting the future. If you are a science fiction author, it might not matter, but if you are trying to design the next game-changing piece of hardware, the stakes are higher.

It seems like, for the most part, even if you manage to get some of the ideas right, the form is often way off. Case in point: telemedicine. Today you can visit a doctor using video conferencing with your phone or a PC for many common maladies. A new idea? Not really. Hugo Gernsback wrote about it in Radio Electronics back in 1955.

Gernsback wrote:

The average medical doctor today is overworked and short-lived. There are never enough doctors anywhere for the world’s constantly multiplying population. Many patients die because the doctor cannot reach them in time, particularly at night and in remote regions.

…[H]e can only see a few [patients] during the day. With increasing traffic congestion, many doctors refuse to make personal calls — execept in emergencies. Even then they arrive often too late. Much of this dilemma will be archaic in the near future, thanks to the Teledoctor.

Gernsback envisioned a doctor using what we now call Waldos similar to what people use to manipulate radioactive material. These super mechanical hands (Gernsback’s words) would allow the doctor to write a prescription, pour liquids, or even diaper a baby thanks to a sense of touch built into them.

Oddly enough, Gernsback’s vision included renting a teledoctor from the drugstore for $3.50 a day. This way, the doctor could call on you and then follow up as well. The drug store would deliver the machine and it would — get this — connect to your phone:

A cord with the a telephone plug attached to the teledoctor instrument is now plugged into a special jack on your telephone. Future telephones will be provided with this facility. The TV signals and telehand electronic signals, etc., will all travel over the closed circuit telephone lines.

In a footnote, Gernsback notes that you can’t send a 525-line TV signal on current phone lines, but a 250-350 line picture was possible and that would be sufficient.

Visionary? In some ways, maybe. The basic idea is coming true today, although it isn’t likely doctors will do surgery or inject you remotely in your home anytime soon. The special telephone plug sort of came true and is already obsolete. The images, by the way, are the ones that accompanied the original article in Radio Electronics.

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