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How to Have the Best Bonfire of the Summer

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Bonfires are pretty much a summer and early fall tradition. You might think they’re easy to throw together in a few minutes, but making a bit more effort will turn a mediocre bonfire gathering into one that you and your friends will fondly remember.

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samuel
5 days ago
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You can never have too much wood at a bonfire. Short on time? Just burn more.
The Haight in San Francisco
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Woman Flying Home To San Francisco Trapped In Barefoot 'Nightmare'

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Woman Flying Home To San Francisco Trapped In Barefoot 'Nightmare' The barefoot woman then used her unshod dog to open and close the plane's window cover. [ more › ]
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samuel
6 days ago
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Small world, Jessie helped design NewsBlur's blurblogs - http://samuel.newsblur.com.
The Haight in San Francisco
ChrisDL
6 days ago
1. unacceptable. 2. Just ask the feet to please not do that?
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Bluetooth LE Standard Gains Mesh Networking for Improved Smart Home Connectivity

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The Bluetooth Special Interest Group today announced that its Bluetooth technology has been updated with support for mesh networking, designed to create large-scale device networks by connecting multiple Bluetooth devices to one another.

Bluetooth calls these "many-to-many" connections, which can support just a handful of devices or up to thousands. In a home setting, the mesh feature will be useful for connecting smart home devices to one another to establish a network that spans an entire house, with no areas that are out of range.


Mesh networks are an improvement over single-point connections because a Bluetooth signal can be transmitted from device to device, reaching further distances. Some products, like the ZigBee-based Philips Hue line of lights, already use mesh networking techniques that are similar to what's being implemented today.

Bluetooth mesh also has many commercial uses, because it creates a reliable network with no single point of failure, it can scale to support thousands of nodes, it supports multi-vendor interoperability, and it offers industrial-grade security. Bluetooth SIG believes Bluetooth mesh will be essential for commercial building and factory automation.

"By adding support for mesh networking, the Bluetooth member community is continuing a long history of focused innovation to help new, up-and-coming markets flourish," said Mark Powell, executive director for Bluetooth SIG, Inc. "In the same way the connected device market experienced rapid growth after the introduction of Bluetooth Low Energy, we believe Bluetooth mesh networking can play a vital role in helping early stage markets, such as building automation and wireless sensor networks, experience more rapid growth."
Existing devices that support Bluetooth 4.0 or 5.0 can be updated with support for Bluetooth mesh, but implementing support requires a firmware update.

Bluetooth mesh networking specifications and the tools that qualify Bluetooth products with networking support are available on the Bluetooth Website. Bluetooth SIG told The Verge that it often takes approximately six months for manufacturers to adopt new Bluetooth technology, but mesh could start rolling out sooner because it doesn't require new hardware.

Tag: Bluetooth

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satadru
8 days ago
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Well this could be really interesting. Lots of questions about power usage, and how this mesh algorithm differs from other stuff out there... and whether this will potentially further clutter up the 2.4 GHz spectrum.
New York, NY
samuel
8 days ago
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RIP Zigbee and Z Wave. Good riddance to competing standards.
The Haight in San Francisco
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Bro Tip: the FLEXR Folding Pullup Bar

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You know a product has been missing from the market when it goes up on Kickstarter and receives 10 times the amount of funding it requested. Recently, that product turns out to be the FLEXR pull up bar, very surprisingly from our research one of the first of its kind. 

Frequent any house occupying swarms of college dudes and you're likely to see a typical pull up bar awkwardly stored behind their Papasan chair or by their towers of protein powder. Founders Derek Pankaew and Eric LaFleche appear to have designed the FLEXR for one to elevate the status of the pull bar as a legitimate design object, but also to solve a problem that frankly should not be that difficult to solve. Considering the company has already raised over $46,000 dollars on a $5,000 goal with 28 days to go, looks like it was high time a designer came up with even a simple solution to this glaring problem.

According to their Kickstarter page, the almost 3 feet by 10 inch equipment folds down to about a quarter of its size at 2 feet by 1 feet. As you can see from the animation above, it isn't the tiniest object you'll ever lug around, although it's considerably better than a standard pull up bar. FLEXR does seem to sacrifice size for the sake of easy foldability and taking away the need for disassembly, which lessens the possibility of losing essential equipment hardware. 

We should also note that the founders of this company are not designers but instead entrepreneurs who hired on designers to help discover a new solution—this inevitably means there is more room for improvement. However, creating something that can at least be easily folded into a duffel bag and stuffed away is a good start. 

Designers, how would you redesign the pull up bar? Is there any way to guarantee more compactness without the risk of losing parts through disassembly? Let us know in the comments below.

FLEXR is currently running a funding campaign on Kickstarter, which you can find here

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samuel
9 days ago
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My pull-up bar is in fact awkwardly stored behind a papasan, but I still use it regularly. The only workout I do apart from biking everywhere.
The Haight in San Francisco
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Bicycle Racing In Space Could be a Thing

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It’s 2100 AD, and hackers and normals live together in mile-long habitats in the Earth-Moon system. The habitat is spun up so that the gravity inside is that of Earth, and for exercise, the normals cycle around on bike paths. But the hackers do their cycling outside, in the vacuum of space.

How so? With ion thrusters, rocketing out xenon gas as the propellant. And the source of power? Ultimately that’s the hackers legs, pedaling away at a drive system that turns two large Wimshurst machines.

Those Wimshurst machines then produce the high voltage needed for the thruster’s ionization as well as the charge flow. They’re also what gives the space bike it’s distinctly bicycle-like appearance. And based on the calculations below, this may someday work!

The Story

The concept of hackers in mile-long space habitats stems from the warped mind of yours truly, but the idea for the space bike comes from a short story called Grand Tour by Charles Sheffield, who was a mathematician, physicist and writer of hard science fiction.

Route for the space bike race
Route for the space bike race

The story is about an annual race called the Grand Tour du Système. The route starts out from low Earth orbit going to Lagrange point 4 (L4), a location along the Moon’s orbit where the Earth’s and Moon’s gravitational fields conspire to provide a stable position. From L4, the route continues halfway to the Moon and then returns to Earth orbit. Altogether it’s around 600,000 kilometers long.

The story doesn’t say how long the race takes but does give clues. The race is broken up into stages wherein the racers cycle non-stop, more-or-less, for around 36 hours. Each stage accelerates from 0 velocity relative to a docking station, then decelerates from a midway point so that the racer arrives at the next docking point also at, or close to, 0 relative velocity. It also says there are 30 variable length stages from Earth to L4, but we’re not told how many stages there are for the rest of the route. But guessing at 60 stages in total, that’s 2160 hours of stop-and-go pedalling (60 stages x 36 hours each).

The Tech: This Could Actually Work

Much of the story is about rivalry and camaraderie, but it’s really a vehicle for talking about the neat tech, and the evolution of it that supplies some plot twists.

Wimshurst machine demo Space bicycle in action

For full details about Wimshurst machines, see our article that walks you through how they work. But basically, each Wimshurst machine consists of two counter rotating disks. Electrostatic induction charges sectors on the disks and sharp-pointed collectors collect that charge and normally carry it away to Leyden jar type capacitors to repeatedly produce exciting sparks. But in this bicycle, that charge is carried away to one of the two ion thrusters.

Given that these thrusters are powered by the high voltage and low current of Wimshurst machines, we can assume they don’t involve electromagnets. Instead they’re probably electrostatic ion thrusters, more akin to many of the ones currently used by satellites and long distance spacecraft, NASA’s Dawn spacecraft being one such example. Xenon is the fuel for many current day thrusters and the closest we find out about what fuel is being used in the story is when one character quips about another “drinking the heavy water again”. However, it is pointed out that for each stage they’re given exactly 50 kilograms of fuel.

How an electrostatic ion thruster works
How an electrostatic ion thruster works

Since the thruster details are missing from the story, we’ll talk about the Dawn spacecraft’s thruster instead. It uses xenon as the fuel. The xenon atoms are injected into the thruster where high energy electrons collide with them, knocking loose an electron and turning them into positively charged atoms, or ions.

The xenon ions then move to a pair of grids, the first one of which is slightly move negative than the positive ions. The two grids are spaced apart 1000 micrometers, or the thickness of ten human hairs. The second grid is more negative than the first and there are 1,280 volts across them. The result is an electrostatic pull on the xenon ions that rapidly accelerates them to 35,000 meters/second toward and through the second grid. It’s then that the rocket reaction takes place, the reaction to the thruster being an equal but opposite 1/50th of a pound (92 millinewton) thrust in the opposite direction. That’s what you feel when a sheet of printer paper is placed on your palm. Keep in mind that that’s from just one ion.

The xenon ions continue through the second grid but then there’s a problem. Since the grid is negatively charged with respect to the ions, the ions would be pulled back to the grid, negating the whole reaction. To counter this, a neutralizer is used which sprays negatively charged electrons into the xenon ions, neutralizing them back to uncharged xenon atoms.

Hacks And Issues

Decelerating using front thruster
Decelerating using front thruster

The first interesting issue that gets pointed out in the story is the problem of how to turn the bike around at each stage’s halfway point in order to begin deceleration. After all, the Wimshurst machine disks are rotating at high speed and act like flywheels — they resist having their orientation changed and so it’s hard to turn the bike around to get the ion thruster pointed in the opposite direction. Instead they had to slow down the Wimshurst machines to the point where they could turn around and then take the time to spin them back up again. That slowing down and speeding up again is not something you want to do when racing.

To get around this, it’s mentioned that someone once won a few stages by secretly adding a second ion thruster to the bike on the front. Decelerating then became only a matter of switching the Wimshurst machine’s output from the back thruster to the front one. Of course, all racers soon added front thrusters too, negating the advantage.

During the current race in the story, one racer comes up with another innovation to win a stage. He redirects his thruster exhaust in a direction that is out of alignment with where he wants to go, but in the direction of the nearest racer. To quote the story:

“We were throwing a couple of tenths of a gram of ion propellant out the back of the bike at better than ten kilometers a second, but we were being hit by the same amount, traveling at the same speed. Net result: no forward acceleration for us.”

Jettisoning unneeded shielding
Jettisoning unneeded shielding

A big topic in space today, especially with all the talk of going to Mars, is radiation. Radiation shielding is heavy and plays a big part in the races. Interestingly, the racers talk about the “weather” as we would on Earth. Of course they’re talking about the solar wind, one of the sources of radiation. We can just imagine future space dwellers speaking in that way: “How’s the weather outside?”, “Windy”.

According to the rules, they can attach as much radiation shielding as they think they’ll need for the forecasted weather. No mention is made as to what the shielding is made of. Naturally the racers want to minimize the mass by minimizing the amount of shielding used. But they can be penalized if they exceed the maximum radiation dosage during a stage.

However, one racer comes up with a radiation related trick to win the final stage and the overall grand tour. The final stage is forecast to have stormy weather, which would peak during the stage. His trick is to modify his bike so that after the storm peaks and declines, he jettisons unneeded shielding. That gives him a lighter bike and so he’s able to go faster and have an easier time decelerating.

Feasibility

Just how feasible is the use of electrostatic ion thrusters powered by Wimshurst machines for a race such as this? That’s a little hard to say since we’re talking science fiction, albeit hard science fiction.

Allowances have to be made to improvements in tech. Even these days there’s a lot of research into ion thrusters. For example, work has been ongoing into removing the need for injecting electrons into the exhaust in order to neutralize it — basically doing away with the bulk, and power requirements of a neutralizer.

We won’t pretend of be experts at orbital dynamics. We know for a fact that some of our readers are and we’d only embarrass ourselves. However, we can do some very basic, and rough acceleration and deceleration calculations. Given total race length of 600,000 km, and assuming it consists of 60 stages, each stage is therefore 10,000 km long and takes around 36 hours. And remember, each stage consists of accelerating from a 0 velocity relative to a docking station, to a midway point, and decelerating back to 0 for the next docking station. So we have 18 hours of acceleration and then 18 more of deceleration.

The formula for distance when accelerating is:

distance = [(vfinal + vinitial)/2]*time

Rearranging for the final velocity and plugging in numbers, we get:

vfinal = (2*5,000 km - 18 h * 0 km/h)/18 h = 555.56 km/h

The formula for the final velocity, if we know the acceleration is:

vfinal = vinitial + (accel * time)

Rearranging that and solving for the acceleration, we get:

accel = 555.56 km/h / 18h = 30.86 km/h^2

This is very rough as it doesn’t taking into account orbits and gravity.

But from the book, when describing the start-up procedure from a docking station we get:

“The starting signal came as an electronic beep in my headset. While it was still sounding I was pedaling like mad, using low gears to get initial torques on the Wimshursts. After a few seconds, I reached critical voltage, the ion drive triggered on, and I was moving. Agonizingly slow at first — a couple of thousandths of a g isn’t much and it takes a while to build up any noticeable speed — but I was off.”

A couple of thousandths of a g is 1/2000 of 9.8 m/s^2, which is 0.0049 m/s^2, or 63.5 km/h^2, and is double the above calculated 30.86 km/h^2. To give some context, a car doing 0 to 60 in 5 seconds accelerates at 43,200 km/hr^2 (accel = 60 km/h / (5 s * 1/3600 h/s) = 43,200 km/hr^2).

So assuming that couple of thousandths of a g acceleration is possible then we might just see hackers pedalling around outside of the habitats some time in the future. In the meantime we’ll have to use our bicycle-powered Wimshurst machines just for creating sparks in the night or hack them to work like strandbeests.


Filed under: classic hacks, Engineering, Featured, Fiction



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samuel
15 days ago
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Slow to start but then you eventually hit 500 km/h.
The Haight in San Francisco
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★ Perfect Ten

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In January 2007, 26 minutes into his Macworld Expo keynote address, Steve Jobs introduced the iPhone with his justly-famous “three revolutionary products” framing:

This is a day I’ve been looking forward to for two-and-a-half years.

Every once in a while, a revolutionary product comes along that changes everything. … One’s very fortunate if you get to work on just one of these in your career.

Apple’s been very fortunate. It’s been able to introduce a few of these into the world. In 1984, we introduced the Macintosh. It didn’t just change Apple, it changed the whole computer industry. In 2001, we introduced the first iPod, and it didn’t just change the way we all listen to music, it changed the entire music industry.

Well, today, we’re introducing three revolutionary products of this class.

The first one is a widescreen iPod with touch controls.

The second is a revolutionary mobile phone.

And the third is a breakthrough Internet communications device.

So, three things: a widescreen iPod with touch controls; a revolutionary mobile phone; and a breakthrough Internet communications device. An iPod, a phone, and an Internet communicator. An iPod, a phone … are you getting it?

These are not three separate devices, this is one device, and we are calling it iPhone.

Ten years ago today, the iPhone went on sale.

I almost never watch an Apple keynote event after it has faded from being new. But I’ve watched the iPhone introduction at least half a dozen times over the years. I still get excited. The words Jobs used, as quoted above, are perfect. But you really have to watch it, to listen to his voice, to feel his conviction. He knew then what we all know now: this was it. This was the keynote we had all been waiting for. This was the reason why people lined up overnight for Apple keynotes — in the hopes of an announcement like this one. The iPhone was the product Apple had been founded to create — the epitome of everything both of Apple’s founding Steves stood for and obsessed about. The home run of all home runs.

With hindsight, though, I think even Jobs himself underestimated what the iPhone was.

The Apple I, the Apple II, the Macintosh, the iPod — yes, these were all industry-changing products. The iPhone never would have happened without each of them. But the iPhone wasn’t merely industry-changing. It wasn’t merely multi-industry-changing. It wasn’t merely many-industry-changing.

The iPhone changed the world.

There is no way to overstate it. The iPhone was the inflection point where “personal computing” truly became personal. Apple had amazing product introductions before the iPhone, and it’s had a few good ones after. But the iPhone was the only product introduction I’ve ever experienced that felt impossible. Apple couldn’t have shrunk Mac OS X — a Unix-based workstation OS — to a point where it could run on a cell phone. Scrolling couldn’t be that smooth and fluid. Touchscreen response couldn’t be so responsive. Apple couldn’t possibly have gotten a major carrier to cede them control over every aspect of the device, both hardware and software. I can recall sitting the hall at Moscone West, watching the keynote unfold, 90 percent excited as hell, 10 percent concerned that I was losing my goddamn mind. Literally mind-blowing.

For nearly six interminable months we waited. And then even once I had my own iPhone in my hands on the evening of Friday, 29 June 2007, I kept thinking, I can’t believe this.

The iPhone’s potential was obviously deep, but it was so deep as to be unfathomable at the time. The original iPhone didn’t even shoot video; today the iPhone and iPhone-like Android phones have largely killed the point-and-shoot camera industry. It has obviated portable music players, audio recorders, paper maps, GPS devices, flashlights, walkie-talkies, music radio (with streaming music), talk radio (with podcasts), and more. Ride-sharing services like Uber and Lyft wouldn’t even make sense pre-iPhone. Social media is mobile-first, and in some cases mobile-only. More people read Daring Fireball on iPhones than on desktop computers.

In just a handful of years, Nokia and BlackBerry, both seemingly impregnable in 2006, were utterly obliterated. The makers of ever-more-computer-like gadgets were simply unable to compete with ever-more-gadget-like computers.

Ten years in and the full potential of the iPhone still hasn’t been fully tapped. No product in the computing age compares to the iPhone in terms of societal or financial impact. Few products in the history of the world compare. We may never see anything like it again — from Apple or from anyone else.

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samuel
27 days ago
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"We may never see anything like it again — from Apple or from anyone else." It's been ten years and in my eyes the floodgates keep getting wider to accommodate all the new inventions and ideas being brought to market. Surely we ain't seen nothing yet.
The Haight in San Francisco
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