Theoretical way to levitate objects with light - <AUTHOR> https://www.caltech.edu/about/news/levitating-objects-light <comment><USER2> As other commenters noted, the title is very misleading. The force exist but it is tiny, very very very tiny.

For radiation, force = power / speed of light

You can add x2 if the radiation bounce against the surface like in a mirror. For the calculations, let's pick a random value for power: 100W

* 100 W it's all the power that used an old incandescent lamp, most of it was wasted as heat instead of visible light, and in many directions.

* A modern LED lamp for a room has about 10W, so 100W are like 10 LED lamps.

* And 100W is HUGE for a laser. And 5W is huge for a laser. (Class 3R is up to .005W and Class 3B is up to .5W.)

So if we divide the force by the acceleration of the gravity [https://www.wolframalpha.com/input/?i=2+*+100W+%2F+(speed+of...](https://www.wolframalpha.com/input/?i=2+*+100W+%2F+\(speed+of+light\)+%2F\(gravity+aceleration\)) we get 7E-8Kg = 70ug that according to wolfram alpha is approximately 1/40 of a typical snowflake and 1/20 of a typical mosquito.

Note that if you suddenly put 100W into a snowflake or a mosquito, they will be destroyed instantly, and you need x20 or x40 more power to make them float, and they will absorb most of the energy so you need x2 the power.

(The article is about manipulating the light/material to stabilize the object, not to magically make the radiation force strong enough to levitate an elephant.)

<comment><USER3> I'm completely out of my element here. Hoping maybe for some clarification.

I've never heard of a laser, at any scale, having a force pushing backwards against the direction of light. It seems like one of two things is possible.

1) you could move a spaceship by shooting a laser. The force would be tiny, but it would keep accelerating as long as the laser is powered, with no reaction mass. i've never heard of such a thing being possible (but, again, way out of my element).

2) you could play the classic impossible machine game, with the fan on the back of a boat blowing into a sail. except with a laser and a sail. If 1) doesn't work, then 2) has to work, right?

<comment><USER2> 1) Yes, but it's easier to use the light from the Sun. More in [https://en.wikipedia.org/wiki/Solar_sail](https://en.wikipedia.org/wiki/Solar_sail)

Also, it is possible to measure this in the lab. For example [https://www.youtube.com/watch?v=Ng1X8mPJziA](https://www.youtube.com/watch?v=Ng1X8mPJziA) Beware that some popular experiments measure tiny difference of gas pressure instead of actual radiation presure [https://www.youtube.com/watch?v=r7NEI_C9Yh0](https://www.youtube.com/watch?v=r7NEI_C9Yh0)

2) If you put the laser an the sail in the same spaceship, and the sail absorbs 100% of the radiation, then the when the laser emit the photons it is pushed in one direction and when the sail absorbs the photons it is pushed in the other direction. So if the sail absorbs 100% of the radiation, the effect in null.

You can use a laser as a strange kind of thruster (if you remove the sail, and point the laser in the other direction). It's very inefficient, but it produces a force. It is not necessary to use a laser, you can use any kind of lamp (and it would be even more inefficient). The heat that escaper from the Pioneer is an involuntary example of this method [https://en.wikipedia.org/wiki/Pioneer_anomaly](https://en.wikipedia.org/wiki/Pioneer_anomaly)

<comment><USER4> That made me think of a totally ridiculous idea for an interstellar ship: The Inchworm Drive.

Put a laser complex in space, which has a laser, a power source for the laser, and enough extra mass (if the power source isn't massive enough) to make the laser complex way more massive than your ship.

Use the laser to push our ship via a light sail.

Have our ship connected to the laser by cables, which we spool out from the ship as it travels, spooling them out fast enough that the cables are not exerting a retarding force on the ship, nor a pulling force on the laser complex (you can probably actually get some thrust from spooling out the cables). Yes, this will require several light-years worth of cables.

Go until the ship reaches the next solar system, and enters orbit around one of the system's outer planets. You need to pick a planet that has resources you can use to refuel the laser power source.

Reel the cables in, using the planet's gravity to keep the ship from getting pulled back to the laser. Doing this, the ship can now pull the laser after it, to the outskirts of the planet's solar system.

Then use the cables to pull the ship back to the newly positioned laser, and refuel it with resources you got from the planet.

Repeat for the next hope of the trip.

<comment><USER2> The problem is that it's not easy to spool out the wires. Just disconnect the laser for a moment to simplify the discussion.

If the ship is traveling at speed V and the wires are at speed 0 in the usual reference frame [1]. If you imagine that you are over the ship, you will see that the wires are initially at rest and you have to accelerate them so they go away from the ship at speed V. So you will have to use a lot of energy to accelerate the wires [2]. And also the wires going away will act like the exhaust of a rocket. If you push the wires backwards, the wires will push you forwards. Now you have a very strange rocket that uses wires instead of some propellent.

[1] whatever it means, perhaps the initial reference frame of the space station that launched the ship, or the average of the local stars.

[2] Assuming that the wires are not so thin, because they have to pull a space station. Also, we are comparing them to a laser beam, so they are in comparison much heavier.

</comment></comment></comment></comment></comment><comment><USER5> This reminds me of a video where someone levitates diamond dust with lasers.

[https://www.youtube.com/watch?v=Sq7GaO8iqu8](https://www.youtube.com/watch?v=Sq7GaO8iqu8)

</comment><comment><USER6> In newtonian physics you learn that momentum is calculated as mass x velocity. Then in modern physics you learn that light has zero mass so you naively assume light has no momentum. Then later you learn that the original equation you learned was missing a piece and light can actually transfer momentum. This is a cool application of that property!

</comment><comment><USER7> Ionic Thruster + Light Levitation = Flying Drone with no moving parts. Wish i can see this in my lifetime.

<comment><USER8> Ionic thrusters for drones? Maybe. Using light? No. Orders of magnitude off even considering the absolute limits of physics. That's not what this article says.

<comment><USER9> I didn't see anything in the article that changes the amount of momentum that would be transferred - as far as I could tell it's all about the distribution of that force being modulated to make the object being accelerated tend to stay in the center of the beam

Editing to clarify my point: the article's title seems wildly misleading by using the word levitation. The energy required to "levitate" a macroscopic object in earth gravity using light is unchanged, and while I don't feel like doing the math right now i feel pretty confident stating that "impractical" is a monstrous understatement.

</comment></comment></comment><comment><USER10> Sorry, here comes probably the usual question asked whenever somebody talks about "light":

if I point a flashlight at an object, does the target object move (in theory, if no other external force exists) because of the light hitting it?

I could expand the question asking: when the light hits, does it lose energy (because some of its energy is transferred to the object that is hit? (e.g. target object heats up and/or moves and/or don't-know-what-else-could-happen) => if yes, then light would disappear if it would bounce around enough times (e.g. if I let light enter a box and then I close it and never open it again, is the light absorbed after a while by the box?)

Personally, I am totally confused. I think that the last time I did some investigations, the simplest statement I found said "light has momentum but no mass" (is this correct, in general?).

That "light has momentum but no mass"-statement confused me even more as I thought that gravity has influence only on things that have mass (what I keep thinking about is the example of the light being bent when it passes nearby a black hole).

Additionally, about "momentum", its definition needs mass, at least as per Wikipedia:

> _momentum (pl. momenta) is the product of the mass and velocity of an > object._ ( > [https://en.wikipedia.org/wiki/Momentum](https://en.wikipedia.org/wiki/Momentum) > )

Therefore if light does not have a mass then it shouldn't be bent by gravity nor have any momentum?

Thx :)

<comment><USER11>
      if I point a flashlight at an object, does the target object move (in theory, if no other external force exists) because of the light hitting it?

Yes, the target object gains velocity due to conservation of momentum. The photon goes from momentum p to -p, so the target object needs to gain 2p of momentum to balance it out. For photons, this amount of momentum is very small.

      when the light hits, does it lose energy (because some of its energy is transferred to the object that is hit?

For perfect reflection, no. (What you're referring to is light absorption, which is a different effect that raises the temperature of the target object and red-shifts the incoming photon.)

      Personally, I am totally confused. I think that the last time I did some investigations, the simplest statement I found said "light has momentum but no mass" (is this correct, in general?).

Pretty much. Photons are usually described by their momentum and energy. For our peace of mind, we can derive an effective "mass" using p=mv, where p is the electron's momentum and v is its velocity; however, the notion is not very useful since it doesn't correspond nicely to our everyday experience of mass (whereas electron momentum does correspond nicely to our everyday experience of momentum).

<comment><USER12> > For perfect reflection, no.

That's not true, it wouldn't conserve energy. The kinetic energy of the object that's hit changes, so the light must lose or gain energy. I think for a reflection this must be because of a red- or blueshift.

> What you're referring to is light absorption, which is a different effect > that raises the temperature of the target object and red-shifts the incoming > photon.

Absorption usually means a whole photon is absorbed, not redshifted. A lower energy photon can sometimes be emitted after absorption (however the direction and phase relation with the previous photon are lost)

<comment><USER10> > _That 's not true, it wouldn't conserve energy. The kinetic energy of the > object that's hit changes, so the light must lose or gain energy._

You mean that as the "path" of the photon is changed by hitting the target object, the vector of the target object must change accordingly? (if yes then how "can" the new vector of the target object computed, if the source object/photon has no mass (I would basically miss a variable for the equation)? IF it does have no mass...)

<comment><USER12> Yes, using its momentum and energy.

Here you can read the relations between a photon's momentum and things like wavelength. Without any mass :)

[https://en.wikipedia.org/wiki/Photon_momentum#Physical_prope...](https://en.wikipedia.org/wiki/Photon_momentum#Physical_properties)

(You need to scroll down a bit for the formulas)

These results come from special relativity(and a bit of quantum mechanics), which you really need if things don't have mass.

<comment><USER10> Thx a lot - next questions follow... :)

(I tried, but the wikipedia chapter is too complicated for me => trying to simplify here)

> _...it 's momentum and energy._

Therefore, if the photon does not have a mass but is still able to have an effect against the target body it impacts with, then the photon must lose energy, right?

[puah - for some reason I cannot reply to the my post's - typothrowaway's - reply...]

<comment><USER12> > (I tried, but the wikipedia chapter is too complicated for me => trying to > simplify here)

I can imagine. That stuff on the wiki is not even in every physics bachelor. It's definitely not for a general audience, but I thought it might help a little :)

> Therefore, if the photon does not have a mass but is still able to have an > effect against the target body it impacts with, then the photon must lose > energy, right?

Yes, or gain it if it slows down the object, if the object is traveling towards the light.

Or the internal energy of the object is changed. This happens when a photon is absorbed.

</comment></comment></comment></comment></comment></comment></comment><comment><USER13> From last year, a 3D volumetric display based on laser manipulation of particles in air: [https://www.nature.com/articles/d41586-018-01125-y](https://www.nature.com/articles/d41586-018-01125-y)

<comment><USER14> Aren't those loud? I saw one that exploded air molecules to create the light.

<comment><USER13> Those are systems with pulsed lasers that ionize the air. This uses relatively low-power beams to trap and illuminate a small particle.

</comment></comment></comment><comment><USER15> The new thing here is not pushing with photons. It's making the thrust self- stabilizing, so the target accelerates without spinning.

</comment><comment><USER16> If they tried to do this with a spacecraft, wouldn't it need constant line of sight from earth with this technique? Seems interesting but pretty impractical for that application, unless I'm reading the text incorrectly.

<comment><USER17> Avi Loeb described this on ep. 40 of After On [1], it didn't sound entirely unrealistic as he described it. It's around 19 minutes into the interview, I see a sibling links Breakthrough Starshot, in this podcast he describes it on a high level.

[1] [https://after-on.com/episodes-31-60/040](https://after- on.com/episodes-31-60/040)

</comment></comment><comment><USER18> Could we use this to make more haptic touch screens?

</comment><comment><USER19> Surprised no-one's yet mentioned the XKCD blogpost on this exact topic: [https://blog.xkcd.com/2008/02/15/the-laser- elevator/](https://blog.xkcd.com/2008/02/15/the-laser-elevator/)

Or the vaguely-related (because lasers) What-If scenario [https://what- if.xkcd.com/13/](https://what-if.xkcd.com/13/)

</comment><comment><USER20> Holy shit, scaling this technology will change humanity. Amazing!</comment>


Banks are too big to see what's coming - <AUTHOR> http://bitcoinmedia.com/too-big-to-see-whats-coming/

<comment><USER2> Let me spare you some trouble. Here's what this article says:

* 10-15% of all transactions are fraudulent. In other words, something like $150Bn-$200bn/yr, or up to 2 times the entire market cap of Cisco Systems, is being lost every year to online fraud.

* Banks are investing in multifactor authentication systems to try to do away with passwords.

* But that won't work, so the only solution is to scrap the entire financial system and start over...

* ... with Bitcoin, for which there is "no payment fraud", "no paper work", "no merchant accounts", and "more privacy".

This argument isn't even coherent enough to be wrong. The types of _mainstream attacks_ modern banking authentication systems are trying to deal with assume customer machines are _actually owned up by attackers_. They'd be happy just to find a way to make it harder to automatically extract value from accounts using standardized malware. This isn't a problem Bitcoin contemplates.

<comment><USER3> _Banks are investing in multifactor authentication systems to try to do away with passwords._

The bitcoin ecosystem are also converging toward that. Or rather, any serious bitcoin payment processor will also be exploring any real security solution, even if it comes from traditional banks.

 _This isn't a problem Bitcoin contemplates._

Think of bitcoin technology as the OS which bitcoin _banks_ run on. There are advantages and disadvantage to using bitcoin as cash, or storing bitcoin with your bank, depending on situations you may encounter.

<comment><USER2> Exasperating.

Bitcoin is on the scale of global commerce simply a thought experiment (or, less charitably, a Ponzi scheme).

So, of course, anything the modern banking system doesn't fully accomplish is "coming soon" for Bitcoin, right around the corner.

Never mind the fact that virtually all Bitcoin development is done either as a hobbyist project or by fly-by-night operations that end up getting fully compromised. No, somehow engineering problems that banks can't solve with tens of millions of dollars of dedicated IT security investment are going to be solved by Bitcoin startups for half-pennies on the dollar.

But, at any rate: exasperating though your argument is, it's also a non- sequitor. My point is that banks are dealing with zombie customer machines controlled by malware. Bitcoin falls to that same threat scenario too.

<comment><USER3> _Bitcoin is on the scale of global commerce simply a thought experiment (or, less charitably, a Ponzi scheme)._

All successful things start small.

 _Never mind the fact that virtually all Bitcoin development is done either as a hobbyist project or by fly-by-night operations that end up getting fully compromised. No, somehow engineering problems that banks can't solve with tens of millions of dollars of dedicated IT security investment are going to be solved by Bitcoin startups for half-pennies on the dollar._

I don't claim that bitcoin startup solve problems that banks can't solve, just that I am asking you to compare bitcoin banks with banks, not bitcoin to banks.

<comment><USER2> So do the unsuccessful things.

</comment></comment></comment></comment></comment><comment><USER4> I would like to see a major player accept bitcoins as a method of payment.

Just imagine for a moment, Google accepting bitcoins as floating currency, to be used in its Google Play service, or with its Android devices with NFC enabled Google Wallet. That would blur the line between digital currency and digital/real goods and services.

<comment><USER5> As a developer who's been following (albeit not too fastidiously) the progress of Bitcoin since it's emergence, I still have no idea how to accept Bitcoin payments. Is there something like authorize.net (or better yet, Stripe) for this? Bitcoin API bindings for the languages du jour would help adoption I'm sure. Though, maybe there are libs out there already and I'm just not aware of them

<comment><USER6> Download bitcoind and learn to use the json interface.

When a buyer comes, generate a new wallet for them. Poll the wallet to see if payment comes.

That's how you accept bitcoin payments.

<comment><USER7> generating a new wallet for every transaction is a bit wasteful, you can however just create a new payment address, and watch for payments on that.

if you create a few hundred receiving addresses, then you can keep the wallet (and hence private key) offline, as all transactions are public, and minimise the risk of having funds stolen (as we've seen a lot of places lately getting hacked and having their accounts drained..)

<comment><USER6> Yeah that's what I meant. Generate a new address for each payment.

</comment></comment></comment></comment></comment><comment><USER8> Yet another one-sided Bitcoin article. Yawn.

</comment><comment><USER9> I think that Bitcoin payment services hold the most promise in third-world countries where credit cards haven't really become the de facto payment standard for non-cash transactions. Any company that could tie Bitcoin with low-end mobile systems available in these countries would be of great service.

<comment><USER10> I don't know if emerging markets are the right place for an inherently deflating currency. That is a lot of continuous forecasting for a financially un-sophisticated population to do, let alone one that generally needs to take on debt to jump classes within a generation.

<comment><USER3> _I don't know if emerging markets are the right place for an inherently deflating currency._

I think you mean a stable or predictable currency. What you need is more volume in the bitcoin economy to stabilize the price. Of course, when the economy grow at extreme rate, the expense of that is a predictable currency. But with bitcoin, you can be certain 99% that it will never exceed 21 millions.

 _let alone one that generally needs to take on debt to jump classes within a generation._

But you don't need debt if you can merely save and jump classes within a generation. If you have saving, you can benefit from extreme growth in the bitcoin economy.

</comment></comment></comment><comment><USER11> I feel like the basic premise is right – there is clearly a lack of regard for the threat posed by the potential for disruptive innovation... AND there is clearly a lack of regard for consumers and merchants (both are users of banking products, of course and both are essential for banks to continue).

If not a completely radical solution like Bitcoins, even some low-margin, relatively more secure solution seems to be more of a question of "when", not "if".

I'm excited to see what happens, personally...</comment>


Ask HN: App review. http://letsphotobooth.com - <AUTHOR>

Hey guys,
Just launched looking for some feedback.
Photobooth hosts weekly webcam challenges. We've launched this week w/ a "killer shades" challenge, so please show your support and snap some pics rockin yours.
The premise is we host "fun" weekly challenges and users snap pics right on the website w/ their webcam.  Facebook Connect is preferred registration method as we post your photos to your facebook account w/ a link back to the site...showing your friends what you're doing.
In addition to that, people earn points for submitting entries, voting, and policing the system. We're thinking of integrating some badges to award to people for special actions.
Ideally, we'd have another section where users submit their own challenges ideas, and the winner's challenge idea is used for the following week.
Please take a look.
Thanks -Steel <comment><AUTHOR> clickable. <http://letsphotobooth.com></comment>


Building Pulse and Bloom, an interactive biofeedback installation at Burning Man - <AUTHOR> http://www.ofbrooklyn.com/2014/09/6/building-pulse-bloom-biofeedback-burning-man-2014/ <comment><AUTHOR> Hey HN, this was my first art installation and boy was it a whopper. Used by tens of thousands of people in 8 days, it had 40 hand-made pulse sensors, 200 high current LEDs, and 40 5 meter LED strips. All running off an ATmega328p chip.

Would love to answer any questions on building art installations.

<comment><USER2> By the way I've shared with the unofficial Burning Man fb group [https://www.facebook.com/groups/burntheman/permalink/1015458...](https://www.facebook.com/groups/burntheman/permalink/10154580583200144/)

<comment><USER3> ...why would you make a Facebook group about this?

<comment><USER4> ... to share snarky comments and bitch about things.

Why does anyone start a facebook group? what about BM makes it non-facebook- group friendly? There are a lot of loosely connect people that meet through BM or regionals, facebook is actually a pretty well-suited platform for discussion.

</comment></comment></comment></comment><comment><USER5> That's a really lovely idea. Congratulations on pulling off your vision.

It's awesome to see how much work went into it. When you're wondering around the playa it's easy to get lost in all the wonderful things going on and not take the time to step back and think about how much work goes into each individual installation.

Every time I see a clip from Burning Man I long to go back there again (I'm in the UK, so it's not so easy). It's surely one of the greatest sensory displays of hackers crafting wonderful work on the planet.

</comment><comment><USER6> I'm interested in biofeedback. And it saddens me that ecg sensors aren't out there for people who aren't electrical engineers (or with equivalent non- formal knowledge in this topic). Neurosky reportedly has one in the works (but probably also 50-100$).

The problem with most heartbeat sensors is that they only give you a frequency. They don't tell you when the heartbeats arrive, or, god forbit, anything interesting about the actual signal.

</comment><comment><USER7> Here's an actual video: [https://www.youtube.com/watch?v=fucQFf7Txws](https://www.youtube.com/watch?v=fucQFf7Txws) (surprised to see there wasn't a video on OP's page)

<comment><AUTHOR> There's a video at the top, it's the first graphic. It is also 42 MB, so it may take a while to load.

</comment></comment><comment><USER8> This is awesome. I just completed a simple first foray into attaching circuits and LEDs to one of my welding projects, and seeing a walkthrough of the steps that I also had to figure out (culminating in an impressive large-scale installation!) is fascinating. Thank you so much!

 _edit_ Btw, also amazing that you were willing to lug the battery back to camp and recharge it via solar power. So many installations out there are marred by the grating sound of a generator in the background.

</comment><comment><USER9> Any issues with the alkaline dust causing issues with the electronics?

<comment><AUTHOR> Oddly no. There's a photo in the post where I show a well dusted board, but no shorts were caused by the dust. There was definitely weatherproofing we could have performed on the boards to handle that issue, but I was waiting until it actually became a problem.

It did rain one day, but only during the day when the installation was off. And thank goodness because if the installation was on, not only would we have a pickle of an issue with all of our exposed wiring, but we would have to get to the middle of the playa in the middle of a rainstorm. It's nearly impossible to move when it rains since the dust cakes onto your shoes and eats everything alive.

<comment><USER10> Yup, was going to mention conformal coating (keyword is important for the electronics side of things). You can get it in a spray can and it goes on like a lacquer, pretty simple (might need to tape certain parts if they need to be exposed). A good conformal coating can withstand the acrid nature of coal plants, I bet it can also handle the playa (though it seems like things fared pretty well as is).

Great project and thanks for the writeup! Hope to see you at future hw meetups in SF! :-)</comment></comment></comment>


The Real Story of How Amazon Built the Echo - <AUTHOR> http://www.bloomberg.com/features/2016-amazon-echo/ <comment><USER2> I have the remote as an early adopter. It's fun to hide in another room and say into the remote "Simon says, hey kids, Kraft no longer makes Mac and cheese and now just makes carrots and ranch dressing."

A moment passes.

"Dad, Alexa just told us...!"

My geek dad game is strong.

<comment><USER3> It's amazing to think about kids growing up with a wonder box in their house that tells them the answer to any question when they yell at it. It's like straight out of the fables or science fiction of the past. I hope this result in people generally having better bullshit detectors in the next generation, and not some other unintended side effect like making them enthralled to said wonder box.

<comment><USER4> What I've wondered is how much non-verbal context will be lost through such an interface. Today, when I'm trying to verify the authenticity or quality of something, it is a game that goes something like this:

1\. Google it and click least spammy looking link (gauged by the URL, although that's no guarantee). I also see what sort of JS they try to load, if it is absolutely bloated with ad tags, etc.

2\. Try to gauge from the design and other content of the site how genuine the answer might be. Are there affiliate links for anything they recommend peppered throughout? That's a signal it might not be unbiased info. Unfortunately, this is where judging a book by its cover comes into play as well. Some poorly designed sites buck the trend, but they are also prominent with spammy sites.

3\. Find other sources to see if there is any consistent logic with said answer/product review/etc.

4\. Make a decision hopefully.

So many of those pieces of the puzzle just aren't available when you limit your input/output to a system like this. There are obvious tradeoffs here--I just hope we don't lose the ability to make more informed decisions. Already I hate things like Apple obfuscating the full URL in the URL bar.

</comment></comment></comment><comment> amzn-336495 The story is that Amazon sacrifices engineers and others after every big project, success or failure. They have developed a weird human sacrifice culture. Fire phone? It was a failure implementing Bezos's wacky ideas. Engineers had to be purged to atone for it. Fire TV? Huge success but we don't want engineers getting any credit for it. Result: purge some engineers. Echo? Another success that now had to float all those managers from both echo and phone project. Better kick some more engineers off the life raft.

[http://www.businessinsider.com/amazon-hardware-division- layo...](http://www.businessinsider.com/amazon-hardware-division- layoffs-2015-8)

They have a real 'slaughter the goose that layed the golden egg because holy shit! there is a huge expensive golden egg and it's mine all mine, die, die, die..." culture. Bezos probably has an employee purge button built into his desk.

<comment><USER5> This startling quote is in the article :

"Many of the people who helped create the Echo no longer work for Amazon..."

As you say, it sounds like success gets punished at Amazon.

<comment><USER6> Isn't it more likely that after shipping a 'named' consumer product, many of those engineers rose in value a tremendous amount and rather than negotiate a raise they took a huge salary bump working for Apple/Google?

<comment><USER5> In my experience, companies are not that great at recognizing and rewarding achievement. So unfortunately, I'll stick to my cynical interpretation. Also, we're talking about dozens or even hundred of people moving on from Amazon here...

<comment><USER6> >In my experience, companies are not that great at recognizing and rewarding achievement.

Is your opinion the crazy stock grants that are happening right now at big tech companies not due to achievement and instead just political or random?

<comment><USER5> Google and Facebook offer largeish stock grants when you join the company, no ? Google is also known, to offer some kind of bonuses on merit, but that policy is seen as remarkable in tech.

I'd guess Amazon is more political and/or stingy than the above 2.

Anyway I was not referring to big tech specifically.

</comment></comment></comment></comment></comment></comment><comment><USER7> I was looking for a fair comparison between Now, Siri, Cortana and Alexa and I stumbled across this [0]. I find it interesting because it seems you would need all of them to answer all your questions.

Do you have also some personal experince comparing with Now , Siri or Cortana? What went really bad or amazed in terms of speech recognition and speech comprehension?

[0] [http://www.cio.com/article/2953989/software- productivity/10-...](http://www.cio.com/article/2953989/software- productivity/10-questions-for-cortana-siri-amazon-echo-and-google-now.html)

<comment><USER8> I can't speak for Cortana, but I have personal experience with Siri, Now, and Alexa. In terms of the actions that I do day-to-day (I would never ask for a dirty joke, for example, but I ask for the weather daily), I would rank them Now, Alexa, and distant third, Siri.

There are two axes that I care about - how many useful commands are available, and how well they can understand me.

Google Now has a pretty wide range of behaviors, but it's the spooky-accurate voice recognition that sets it clearly ahead. In the last year, Google Now has only misunderstood me ONCE.

Alexa also has a very wide range of behaviors (especially with the Skills), but I do occasionally run into things I feel like it should do that it doesn't (yet). To be fair, I also use her the most, so it could be that I push her further than the others. The voice recognition is quite good; I would say it misunderstands me less than 5 times in 100.

Siri is by far the worst. Her abilities are limited, but worse, she has a tendency to funnel commands that she can't do into things she can. For example, asking for the hours of a restaurant will instead show you a Bing search (!) for the restaurant's name, sans hours. This is not useful. It would be better to just inform me that she can't do that yet, file that in a log at Apple, and then add that behavior some time down the road.

She also mishears me 25-45% of the time, AND she seems to be getting worse over time. I assume this is because they are trying to widen her audience beyond a standard California accent, but it's incredibly frustrating for a product to get worse, not better, over time. I now use her only for voice dictation of texts on my iPhone, and use Google Now in app form exclusively for more advanced queries.

<comment><USER9> > Google Now has a pretty wide range of behaviors, but it's the spooky- > accurate voice recognition that sets it clearly ahead. In the last year, > Google Now has only misunderstood me ONCE.

> She also mishears me 25-45% of the time, AND she seems to be getting worse > over time. I assume this is because they are trying to widen her audience > beyond a standard California accent, but it's incredibly frustrating for a > product to get worse, not better, over time. I now use her only for voice > dictation of texts on my iPhone, and use Google Now in app form exclusively > for more advanced queries.

And this is pretty much a huge issue for this market. Entry requires having already spent several billions on voice tech.

You'd have to practically use all of YouTube as training set. Which Google did.

Maybe someday we can have laws that require all neural networks trained with data from others to be in the public domain, even if the people providing training data agreed to the data being used for training.

Then we could compete on other things than "understands voice".

<comment><USER10> I don't think it will take billions. LSTM+CTC speech recognition implementations are coming to OSS and I think we have large enough available data sets for training without needing Google size resources. Audio books are a good resource for training and it's not hard to amass hundreds or thousands of hours of training material that way. I think we will have 95%+ accuracy ASR as open source trained networks very soon.

In the case of Amazon Echo/Dot they benefit greatly from the far field array mic for isolating a clean speech signal in noisy/far field environments, would be nice to see generic USB array mics with Linux drivers

<comment><USER11> What's the OSS LSTM+CTC package that's coming along?

<comment><USER10> [https://github.com/srvk/eesen](https://github.com/srvk/eesen)

I expect there will be something in Kaldi soon, too

</comment></comment></comment></comment></comment></comment><comment><USER12> > "Generally, the engineers and product managers at Lab126 quelled their own > dissent before it reached Bezos, instead concentrating on giving the boss > what they thought he wanted. "We spent so much time trying to anticipate > what Jeff would do or say, and read into little words he would say in > meetings," said one former employee. "It would lead to so much additional > work."

This sounds like a recipe for disaster. Very worrying. How have they managed to be so successful with such broken communications?

</comment><comment><USER13> I am waiting for the day when someone will sneak in those magic words into a TV commercial to wake up Echo, Siri, etc. Imagine like a DDoS caused by a TV commercial on Super Bowl.

I have the Echo and sometimes it scares the * out of me when something on my TV sounds similar to "Alexa", like "a lexus".

<comment><USER14> Yeah, they call the activation word a "wake word", but I couldn't help but think of it as a "safe word". It needs to be something that you're only likely to say when you _mean_ it. Which, to me, implies it should be customizable. I should be able to set it to whatever makes sense for me.

This issue comes up in science fiction stories, often set on spacecraft, where there is an AI that is spoken to. On Star Trek, they just said "Computer?" and that got it's attention. But that always seemed a little clunky to me. At first I thought the ship AI should have the same name as the ship, but I quickly realized that probably wouldn't work so well. Picard: "This is the USS Enterprise!" Computer: "Yes?" On Babylon 5, a Minbari character just called his ship, "ship", and in Alien, the ship was Mother, etc. I decided that if I ever wrote an SF story with a shipboard AI (or HAD a ship with a shipboard AI :) I would call it Maru-san.

</comment></comment><comment><USER15> reads like a PR piece. does Amazon Echo really need a "the real story" piece? it's barely been out...

<comment><USER16> Probably not a coincidence that the Echo is on sale today[0].

[0] www.amazon.com/Amazon-SK705DI-Echo/dp/B00X4WHP5E

</comment></comment><comment><USER17> > You can use Alexa to turn off the lights, ask it how much gas is left in > your car, or order a pizza.

I'm getting a bit tired of these examples. Is there a comprehensive list of things Alexa can do?

<comment><USER18> Such a list doesn't exist for the Echo any more than it does for your cell phone. The Echo is integrated into IFTTT, so any of the actions here [1] are available, and there are also an ever expanding list of actions called 'Skills' [2] that you can add to your particular Echo's list of available integrations (like installing a phone app).

That's all in addition to the basic things it can do out of the box, like set timers and reminders, manage a todo list, play music and books (from an admittedly limited set of sources), tell (mostly bad) jokes, sync with your google calendar and respond to questions about upcoming events, tell you the weather forecast, read off headlines, and a bunch more.

To a greater or lesser extent, it's like a living room installation of Siri.

[1] [https://ifttt.com/amazon_alexa](https://ifttt.com/amazon_alexa) [2] [http://alexa.amazon.com/#skills](http://alexa.amazon.com/#skills) (might require you to already have an Echo)

<comment><USER19> You could, in theory, list every verb my phone can natively perform. That list is the set of view controllers in the phone's onboard OS apps, plus the set of view controllers in every app in the app store (which is growing, but finite and still easily enumerated.)

The only assumption you need to make is that actions on all server-delivered forms are collapsed into a single "make a network request" verb; otherwise you _do_ get the infinite expanse of actions that is the web.

</comment></comment></comment><comment><USER20> Maybe I'm old but i still really don't understand the appeal of a device that monitors and datamines all the communication in your home so you can buy products more easily.

<comment><USER21> Not sure just how seriously this is meant to be taken, but the Echo doesn't monitor anything until you say "Alexa" (and recognition of that is handled in the hardware, locally - if you're worried about devices with net access and microphones, you'll need to keep your phone turned off at home, too). It's fair to assume that once you are interacting with it Amazon mines at least some data, however.

<comment><USER20> >but the Echo doesn't monitor anything until you say "Alexa"

then how does it know when you say Alexa?

<comment><USER22> Because the code that understands 'Alexa' is hardcoded into the device. Once it hears that word, that's when audio starts getting sent over the Internet to Amazon's servers.

</comment></comment></comment></comment><comment><USER23> When is Google going to build a Google Now for the living room to compete with Echo? I want an Echo, but I think a Google product with access to the whole Google ecosystem would be more useful to me.

We know Echo will never play nice with Google (you can't buy Chromecast on Amazon is evidence). If Google built this product, the only feature they probably couldn't match would be buying products on Amazon, which I don't know if I would use anyway.

</comment><comment><USER24> I really want an Echo, I just can't justify the cost. And the cheaper options don't have the listening mode which nerfs the whole appeal.

<comment><USER25> I got early access to pre-order (can't remember why) at $99 and almost didn't do it. I'm SO glad I did. It gets used all day every day. I grab the last two eggs and say "Alexa, add eggs to the grocery list", hands are full of mess while cooking, "Alexa, set a timer for 5 minutes", etc. The fact that it works with my home automation hub is also nice, when I'm across the room and want the lights off, or want the garage door closed. I could live without it for sure, but it just makes things easier. The voice recognition, especially from far away is incredible. I don't have to yell, or say things exactly right (like in my car).

Knowing what I know now, I'd pay full price- especially with the new functionality and apps that get released every week it seems. I've even written a few of my own.

The speaker itself is just okay, we play music on it all the time for the kids, but there are way better Bluetooth speaker setups, so if that's your primary goal you won't be that excited.

If you can afford it and have a routine of any sort throughout the day where checking the weather, traffic, maintaining a grocery list (especially when you might not be the person going), getting a news briefing or listening to a podcast are part of it, then you'll find it useful immediately. If you don't, to get your money's worth, you'd want to start a routine of sorts.

<comment><USER24> I have a gen 1 iPad mini taped to my fridge so I have voice control with Siri and I don't think Alexa can do anything Siri can't (for me). I want one, I just don't think I need it. I'd love to automate everything though.

</comment></comment></comment><comment><USER26> Bloomberg's 404 is...

[http://www.bloomberg.com/404.html](http://www.bloomberg.com/404.html)

</comment><comment><USER27> Maybe it's time to release it in other territories now

</comment><comment><USER11> I've played with the Echo, it is really nice, but ... much like Siri, Cortana and Google Now, using it fully gives up any shred of remaining privacy you had within your own home. I would gladly pay twice as much for an Echo-device that doesn't route all my instructions through $BEHEMOTH servers.

</comment><comment><USER28> There was another long article about this a week ago with almost an identical title: [https://news.ycombinator.com/item?id=11416795](https://news.ycombinator.com/item?id=11416795).

</comment><comment><USER29> ugh, please no gifs, I'm trying to read here!

Big quotes I already read in the text are similarly annoying...

</comment><comment><USER30> I wonder what conversation at bloomberg resulted in adding all of those extremely distracting (and annoying) animated gifs..

<comment><USER31> Holy crap that is annoying. Is there a way to pause all animated gifs in chrome? Congratulations, Bloomberg, you captured the essence of a Geocities site. This has to be a not so subtle graphic design joke.

<comment><USER32> I opened up Chrome Developer tools and added img { display: none } which hides everything but the top banner, which you can scroll past ;)

<comment><USER33> I have uBlock Origin, and it was as simple as right-click>Block Element and selecting the suggestion of amazon_echo_animation_ _.gif

The filter for the curious:

        ||www.bloomberg.com/features/2016-amazon-echo/amazon_echo_animation_*.gif

</comment></comment></comment></comment><comment><USER34> "An e-commerce company wouldn't seem like an obvious leader in [augmented reality]."

Amazing that even today articles are still calling Amazon an e-commerce company. I wonder if this is an image Amazon actively cultivates or if it's just consistently lazy reporting?

<comment><USER35> It's possible the author of the article knows that Amazon is now a tech company as well, but is assuming that their audience does not yet realize this. My impression is that people who don't work in tech don't know this; I have explained many times to people outside of our world how Amazon is one of the most important tech companies in the world, and that discussion always starts with a puzzled look from them.

<comment><USER34> Yeah, that's kind of my take as well. But I put that in the lazy reporting category.

Seems like it would be worth the paragraph explaining the misconception and helping people realize why the seemingly weird stuff Amazon kinda does makes sense.

<comment><USER36> Don't feel bad -- we at Bloomberg always get classed a "media" company when the media properties came about a decade after the software (& hardware). It's just easier to say because it fits better into public expectation. To most people Amazon is e-commerce because nearly everyone buys things from them online or via mobile apps.

<comment><USER37> If this sub-thread were not about being specific in one's characterization, I would not point this out, but:

> online or via mobile apps

As far as I'm concerned 'mobile apps' operate 'online' and it isn't clear the distinction you are making. Is it common to refer to 'online' as via a web interface (ports 80/443)?

<comment><USER38> I think that's the distinction and I think it's a valid one. My experience on Aliexpress, Amazon, and Ebay (to name the 3 I use the most) is that the web and mobile interfaces and use cases are still quite distinct from each other. On Aliexpress, I sometimes use the mobile to checkout for the explicit discount, but never search from mobile. On Ebay, I respond to bidding alerts on mobile, but don't initiate transactions/searches on mobile. On Amazon, I basically never use their mobile app (and usually use google to search Amazon's [web]site).

</comment></comment></comment></comment></comment></comment><comment><USER39> > Generally, the engineers and product managers at Lab126 quelled their own > dissent before it reached Bezos, instead concentrating on giving the boss > what they thought he wanted. "We spent so much time trying to anticipate > what Jeff would do or say, and read into little words he would say in > meetings," said one former employee. "It would lead to so much additional > work."

That sounds like a questionable at best policy.</comment>


Show HN: Editdit – Video/Image/Meme Generator Using WebAssembly, No Watermark - <AUTHOR> https://www.editdit.com/ <comment><AUTHOR> Hi, guys, any feedback is appreciated!;)

As far as I know, this site works best with Chrome on Android, Windows and Mac for now. Sorry for the inconvenience this may cause you.</comment>


Show HN: Tool to get better feedback on your landing page - <AUTHOR> https://unfaint.com <comment><AUTHOR> Maker here: I've only just built and released this and there may be a few bugs here and there. Please let me know if your landing page doesn't work!</comment>


Greplin Wants You To Redesign Wikipedia Search - <AUTHOR> http://techcrunch.com/2011/07/26/greplin-wikipedia/

<comment><USER2> The reason Wikipedia's search is broken isn't (only) because it doesn't take advantage of the interesting data representations you can use; it's also just a really shitty search algo. It doesn't make any guesses, it doesn't look at related terms, and it often won't bring up the relevant article unless you specifically type that article's name.

There's a huge opportunity to beautifully represent information on Wikipedia and make search easy, intuitive, and informative, but it all rests upon having a search algo that isn't utter crap. The WMF will have to fix that before any of this will have any practical benefit.

As an ironic aside, it seems that Wikipedia isn't OSS. I can find the repo for MediaWiki, but Wikipedia seems to be a heavily modified version thereof, and it appears to be proprietary. If anyone can find the repo, I'd appreciate a link.

<comment><USER3> What do you mean by heavily modified? Wikipedia is running version 1.17wmf, basically 1.17 with some fixes pulled from trunk. You'll find it here: [http://svn.wikimedia.org/viewvc/mediawiki/branches/wmf/1.17w...](http://svn.wikimedia.org/viewvc/mediawiki/branches/wmf/1.17wmf1/)

You'll find the installed extensions here: <http://en.wikipedia.org/wiki/Special:Version>

</comment></comment><comment><USER4> Most people use Google search for Wikipedia because it's simply easier, instead of navigating to Wikipedia and then typing in your search, just type in your search where you usually do. Nothing you redesign on wikipedia.org will ever change this fact, people's shortest point of access to a specific Wikipedia article will still be their browser search bar or homepage set to Google/etc.

If Wikipedia's search can be improved it's simply from an accuracy standpoint. I would guess that Google employs more sophisticated spelling correction, stemming, auto completion, etc. Developing all these features to Google's level is very expensive and in that case it might make a lot of sense to just use Google's technology for the Wikipedia search.

</comment><comment><USER5> A few years ago, I decided that I wanted to make a really good Wikipedia search engine. I downloaded the entire Wikipedia dataset, I downloaded DBPedia, I setup graph database, wrote code to query everything using SPARQL/RDF, and after much trial and error, went a completely different route: Google Ajax/JS Search API

<http://chir.ag/wiki/cat+disease+brain>

I did this because in the end, Google still gave very good results very fast. I made mine search-as-you-type so if I wasn't satisfied by the results, I could reedit my search text instantly.

I know because of Wikipedia's no-corporate-alliance reasons, they probably won't use Google search. If you're thinking of answering Greplin's call based on textual-analysis, my gut instinct says you will have a VERY hard time beating Google. However, if you go the DBPedia route, you might end up with something really neat. Powerset did something similar and got bought up by MS.

<comment><USER6> It should be noted that the challenge is for design, not for actual search algorithm implementation or anything technical.

<comment><USER7> I hope that the winning entry will be an actual implementation. It's not hard to have ideas to improve Wikipedia's search; the hard part is writing the code.

</comment></comment></comment><comment><USER8> The thing is, Wikipedia's search is pretty straightforward: type keyword, arrive on article page.

Anything you'd add to that would detract from the search experience, not improve it. Seems to me the reason why people use Google to search wikipedia is because it saves them a step, not because wikipedia's search is inherently broken.

In any case I'd like to take part in the contest, but so far I can't really think of a way to improve wikipedia's search…

<comment><USER9> The problem is when your search doesn't bring you immediately to the right article -- if it's not a simple search term like "Bermuda Triangle" -- and you end up looking at a page of results like this:

[http://en.wikipedia.org/w/index.php?search=wireless+router+f...](http://en.wikipedia.org/w/index.php?search=wireless+router+firmware)

Those are actually pretty good results, but their presentation is lacking. The snippets of article text are too short to give a proper idea of what the article is about and how it relates to the query terms. The formatting is straightforward but not particularly good or bad. The article metadata in green is nigh-useless to the vast majority of people; do you want text like "11 KB (1,170 words) - 12:19, 10 July 2011" cluttering up each search result? The section headings, like "Content Pages" and "Multimedia" are simple links, and it's not visually obvious under what circumstances you might want to click them, or what will happen if you do.

That's just off the top of my head, and I'm not a designer; just someone who cares about usability. I imagine a good designer could make something quite a lot nicer than Wikipedia's default search pages.

</comment></comment><comment><USER10> I type "en<tab>" and then enter my query (in Chrome, at least). Doesn't get much better than that.

However, if I didn't have that feature, I'd probably use Google anyway. Tweaking the CSS won't change that. They'd really have to make Wikipedia's search kick ass in some other way.

<comment><USER9> Does Chrome's search give you realtime term completion? If you start typing in the search box on Wikipedia, it will give you suggestions that are the titles of articles. It's a substantial usability improvement over just typing something, since it gives you the opportunity to skip directly to a page more often, rather than going through the vigorously mediocre search results page.

<comment><USER3> Of course it does.

<comment><USER9> Huh. Maybe I need to update Chrome, because it's not working for me. Weird.

EDIT: It was just a hiccup when I checked; the problem is gone now. Thank you for pointing that out; from now on I'll use this method to search Wikipedia.

</comment></comment></comment></comment><comment><USER11> My girlfriend still types Facebook into Google to go to Facebook. I don't think it's an issue with Wikipedia.

</comment><comment><USER12> I hope the winner gets built as a customizable addendum to the Mediawiki code and released as an extension. This way if Wikipedia doesn't use it other Mediawiki instances can.

</comment><comment><USER13> Here's a better search, I've mapped it as a keyword w [http://google.com/search?q=site:en.wikipedia.org/wiki/%20%s&...](http://google.com/search?q=site:en.wikipedia.org/wiki/%20%s&btnI=I%27m+Feeling+LuckyI%27m%20Feeling%20Lucky)

thus you can type 'w india china war' and it returns: Sino-Indian_War

<comment><USER14> > thus you can type 'w india china war' and it returns: Sino-Indian_War

That's the first result for Wikipedia's internal search, too: [http://en.wikipedia.org/w/index.php?title=Special:Search&...](http://en.wikipedia.org/w/index.php?title=Special:Search&search=india+china+war)

</comment></comment><comment><USER15> Using the actual Wikipedia search involves an extra step where I google for "wikipedia". I can skip this step if I just google for the thing I want directly on Google.

I think that says more about how good Google is than how bad Wikipedia is (although I do agree that the Wikipedia results page needs work).</comment>


[Update: Resolved] Slack no longer supports PDF uploads - <AUTHOR> https://twitter.com/EricMann/status/1301214485043126272 <comment><USER2> 1 tweet with no verification by the HN poster or confirmation from Slack. Suddenly:

"Slack no longer supports PDF uploads".

Slack responded within 20 minutes of the tweet [1]:

> Hi Eric, we do still support PDFs! Can you try a different PDF and let us > know if it gives the same error?

I checked myself - I can upload PDFs to slack still.

[1]: [https://twitter.com/SlackHQ/status/1301217226507325443](https://twitter.com/SlackHQ/status/1301217226507325443)

</comment><comment><AUTHOR> Update - there was an intermittent error in the Linux client preventing Slack from reading or uploading PDFs. This has since been resolved.</comment>