Solid-state battery startup claims breakthrough for electric vehicles - <AUTHOR> https://electrek.co/2018/09/11/solid-state-battery-startup-bmw-hyundai-samsung-breakthrough-electric-vehicles/ <comment><USER2> Precious little detail on the batteries themselves. As with all solid state batteries, power is the Achilles heel. I'm skeptical this battery can make provide the 1+ C a car needs to run on the highway, but it's possible it may in the future.

According to [1], the specific energy is ~300 Wh/kg- the best li ion cells are ~275 Wh/kg, but only barely. When the OP article refers to 2-3x capacity improvements (2x on the website), it refers to energy density, or Wh per liter. That's not really considered an important metric except for phones. Unfortunately, the battery has to be over 150 Celcius for the solid electrolyte to work, so don't expect better phone batteries any time soon.

The way this would work is that cars would have a small conventional battery of ~15-30 kWh that could supply acceleration power and preheat the solid state battery. The larger battery would just back it up on long trips. How attractive this is depends 100% on how much power they can crank in the battery, since it isn't _that_ much bigger than a normal battery.

Lots of people think solid state batteries will eventually replace liquid electrolytes, but it's effectively anyone's guess. We've had a lot of trouble finding high-power solid electrolytes for a looong time. The main benefits are safety related right now.

The basic reason is that conventional cathodes are highly oxidizing, so when a liquid electrolyte gets too hot it steals that oxygen and breaks down, causing a runaway reaction. Solid electrolytes and metallic cathodes don't have extra potential energy, so when there's damage to the cell like a short or overtemperature it simply burns itself out. The solid electrolyte is also far more stable and isn't very subject to breakdown from overtemperature or overvoltage.

[1]: [https://qz.com/1383884/a-startup-promising-an-all-solid- stat...](https://qz.com/1383884/a-startup-promising-an-all-solid-state- rechargeable-battery-has-raised-20-million/)

<comment><USER3> I gather "1+ C" is "power capability" as explained at [https://learn.adafruit.com/all-about-batteries/power- capacit...](https://learn.adafruit.com/all-about-batteries/power-capacity-and- power-capability) ?

With current batteries, there are just many tiny 18650 cells connected in parallel / series to get the desired power and voltage, right? Are you saying there are some unstated engineering limitations that would hinder getting to the desired "C" by connecting more battery cells in parallel?

<comment><USER4> > Are you saying there are some unstated engineering limitations that would > hinder getting to the desired "C" by connecting more battery cells in > parallel?

When connected in parallel, each cell has to discharge at same rate within a small margin. That means you have to match cells by capacity and internal resistance during manufacturing process. The more cells you put in parallel, the more chance some of them will age differently and cause whole battery to underperform or fail spectacularly.

<comment><USER5> Could you elaborate why would that affect the battery as a whole?

And why the batteries have to discharge at the same rate in the first place?

<comment><USER6> Because the load is spread equally if there is a difference in the capacity / internal resistance of the battery it can cause a higher load on it than it can safely discharge at that moment.

That said this is a problem with all batteries which is solved trough rebalancing: [https://en.m.wikipedia.org/wiki/Battery_balancing](https://en.m.wikipedia.org/wiki/Battery_balancing)

Without this we wouldn't ba able to make battery packs with 100s not to mention 1000s of cells and even smaller battery packs would die much much sooner.

A good analogy would be if you have a boat with multiple people rowing and one of them can't hold the same pace if you don't adjust for it you aren't going to hold course and if you don't let the man catch a break they'll pass completely eventually.

</comment></comment></comment></comment></comment><comment><USER7> Most battery announcements are bogus, but this one might be real. A123 Systems, the developer of lithium-iron-phosphate batteries, is involved. They put in $20 million as a Series A.[1] If you have a Crunchbase account, you can see more of the terms for this round.

[1] [https://www.crunchbase.com/funding_round/solid-power- series-...](https://www.crunchbase.com/funding_round/solid-power-series-a-- 9435192)

<comment><USER8> Investment doesn't mean they have a viable product though.

See also Theranos, Clinkle, Yo.

<comment><USER9> Cuil, magic leap, ... (never forget cuil)

<comment><USER10> Ah I remember going on cuil back then. Just read up on why they shut down and this is appalling: (from Wikipedia)

>... on the morning of September 17, 2010 "employees were told about Cuil's demise [...] and the servers were taken offline five hours later." Laid-off employees were told they would not be paid.

</comment></comment></comment></comment><comment><USER11> For those dismissing this as a yet another lab breakthrough without substance, the article is about this company getting quite substantial funding for what looks like a pretty nice series A funding round.

It looks like there are some serious investors involved that clearly believe that these guys know what they are doing. They presumably did their due diligence. That generally means this company used some seed funding to do proof of concepts and prototypes that are showing some promise.

In any case, 20M is nice but clearly nowhere near enough for mass producing stuff like this. So, what this means is this company just received funding to do more R&D from a nice consortium of investors that would clearly benefit from having a stake in a company like that if it had at all any chance of succeeding. Presumably there are still some hard problems left to work on otherwise, we'd be reading about some company investing billions to actually build the factories to mass produce this.

Since there are now several companies working on solid state batteries, the chances seem pretty good that one of them will eventually come up with viable products that can be produced at a quality, scale and cost that is interesting.

IMHO that will likely happen second half of the next decade or so. One application where this stuff might be applied early might be electric planes. That's a use case where improved energy density and safety is so valuable that even a very expensive solid state battery might still be interesting.

<comment><USER9> Funding and/or "serious investors" or even serious people on the board or as advisors means literally nothing. Theranos checked literally all of those boxes, and even got a visit from the Vice President and an award.

And they never even had a product that worked, and what devices they did have were fraudulent.

Having high profile people involved should never have been relevant to the quality of product coming from a company, but now that we are all aware of Theranos is should be absolutely clear to everyone that it is meaningless. It is likewise meaningless to make claims without backing it up with results from at least an independent third party if not making devices available to multiple technically competent reporters.

<comment><USER12> Not accurate. Theranos's investors, board and outside stakeholders where by design people with no medical or related experience.

<comment><USER13> Also in the Theranos case there really was only one major customer i.e. Wallgreens who then failed to do proper due diligence. Here you have multiple car manufacturers involved who specialise in vetting new technology for mass production.

<comment><USER14> We're in a post-Theranos world. Companies are going to be getting a little extra scrutiny.

Also, as near as I can tell, Theranos got their later investment rounds by being willing to wildly lie. IIRC, they claimed something like $100e6 of revenues where the actual number was approx $100e3 [1]. That is probably going to (slowly) lead to criminal liability for some of the principals.

Here (as parent mentioned) you have battery companies investing in a battery company.

[1] [https://www.cnbc.com/2018/03/14/theranos-president- exaggerat...](https://www.cnbc.com/2018/03/14/theranos-president-exaggerated- revenue-by-1000x-says-sec.html)

<comment><USER15> _We 're in a post-Theranos world._

Which was in turn in a post-Enron world. The one sure way to make sure that crap can keep happening is to pretend that something has really changed, so it can't happen again. It can, stay vigilant.

</comment></comment></comment></comment></comment></comment><comment><USER16> I encourage everyone to read the article before dismissing this news as yet another snake-oil press-releases - there is plenty of background there and it appears that that both BMW and Hyundai are investing, among others, giving some credence to the story.

<comment><USER17> BMW and Hyundai investing doesn't mean nothing. But it also doesn't mean a lot. There are a ton of battery startups that have highly speculative investment from respectable companies. They invest because the prize is so big. If they really have done what they claim then it is worth many many billions.

</comment></comment><comment><USER18> These guys have been around with the same story for the last 5 years.

[https://www.colorado.edu/today/2013/09/18/solid-state- batter...](https://www.colorado.edu/today/2013/09/18/solid-state-battery- developed-cu-boulder-could-double-range-electric-cars)

</comment><comment><USER19> > capacity "2-3X higher" than conventional lithium-ion

Is this per unit weight? per unit space? per dollar?

<comment><USER20> If it's per unit space, it's effectively a bomb. Doesn't mean it has to be unsafe. We drive around with big tanks of gasoline. But stored energy is stored energy.

<comment><USER2> > If it's per unit space, it's effectively a bomb.

No, not particularly- the energy stored in an li ion cell is only a small amount of its potential energy. The cathode (eg cobalt oxide) and the organic electrolyte act as an oxidizer and fuel, >10x more energetic than the energy stored in the lithium.

Solid state batteries carry far _less_ energy than a normal battery.

<comment><USER20> How could that be the case if they hold more energy or are more dense? It's just physics.

I wasn't saying they couldn't work, just that if they did fail they'd have the potential to fail spectacularly. Same is true for a gasoline tank.

<comment><USER2> If solid state cells had 3x more energy per volume, they'd have slightly _less_ energy to release than a normal li ion cell, and those aren't bombs. Flamethrowers at worst.

A bomb requires way more than just energy, it needs to have a mechanism to release quickly. Li ion has a mechanism like that, but solid state batteries don't.

</comment></comment></comment></comment></comment><comment><USER21> The title seems misleading. There doesn't appear to be any new technology here, just a funding round announcement.

 _In a press release, the company listed a bunch of advantages that they claim their technology has over current batteries_

The aversion to link to source documents really hurts the credibility of publications like this. It forces me to try to find the "press release" on my own. Ok, here it goes.

I went to the Solid Power press release page and found nothing about a breakthrough - indeed nothing since last June, and then nothing of technical note:

[https://www.solidpower.com/en/news/press- releases/](https://www.solidpower.com/en/news/press-releases/)

The blog has one more recent entry, but it's just a trade show event:

[https://www.solidpower.com/en/news/](https://www.solidpower.com/en/news/)

Oddly, neither page mentions the recent funding round.

</comment><comment><USER22> I found this comment in the article refreshing: _Solid-state batteries are thought to be a lot safer than common li-ion cells and could have more potential for higher energy density, but they also have limitations like temperature ranges and electrode current density. Not to mention we have yet to see a company capable of producing them at large-scale and at an attractive price point competitive with li-ion._

So far all of the solid state batteries that I've read papers on suffer from an inability to charge quickly because they cannot dissipate heat fast enough. The whole swap the battery packs thing is a work around for this where you get a car and 'n' battery packs. Charge the packs slowly (limitation of battery) but swap packs quickly (mechanical issues, not a problem). To my way of thinking such a solution is fine for a commuter car but exacerbates the range issues. Maybe that is ok in this space but so far until Tesla's "300 mile range" cars hit the market EVs were pretty niche.

</comment><comment><USER23> Title should be "ANOTHER Solid-state battery startup claims breakthrough for electric vehicles"

<comment><USER24> ...and it's "5-10 years away", just like all the others we've been hearing about for the past 15 years.

</comment></comment><comment><USER25> Another one to check on in 18 months.

<comment><USER26> Yeah quite a few at it:

>Major companies present in All-Solid-State Battery market report: BMW, Hyundai, Dyson, Apple, CATL, Bolloré, Toyota, Panasonic, Jiawei, Bosch, Quantum Scape, Ilika, Excellatron Solid State, Cymbet, Solid Power, Mitsui Kinzoku, Samsung, ProLogium ,,

<comment><USER27> And Ionic Materials ([http://ionicmaterials.com](http://ionicmaterials.com)) which also received investment from big industrial companies over the last year.

</comment></comment></comment><comment><USER28> It is getting annoying... Everyone has a breakthrough technology... no one has a real battery.

<comment><USER29> The galaxy brain take on Tesla is that it is just marketing wrapped around the progress that was already happening in batteries. They really actually are cheaper and have much increased energy density relative to 10 and 20 years ago.

<comment><USER30> > They really actually are cheaper and have much increased energy density > relative to 10 and 20 years ago.

But have they implemented any of these 'breakthrough' technologies?

<comment><USER29> Does lithium-ion itself count? The first practical chemistry was developed in 1979, the first commercial battery was shipped in 1991 and they went pretty mainstream between 2000 and 2005.

That's a long time if you are talking about announcements made today but there's been lots of announcements in between and there is considerably more investment now than 30 years ago.

<comment><USER30> If we're looking at breakthroughs since 30 years ago, lithium ion definitely counts. But it's pretty much the only example, and there are very severe flaws with lithium ion leaving the space ripe for improvement. Everything since has pretty much been optimization.

</comment></comment></comment></comment></comment><comment><USER31> There is a great video from GreatScott on youtube[0] about LCB (Lithium Ceramic Batteries) where he got hands on some of them and tests them for charging, usage and physical resilience (they work even if you cut off large parts of the battery).

0: [https://www.youtube.com/watch?v=kJXRyWQgOY4](https://www.youtube.com/watch?v=kJXRyWQgOY4)

</comment><comment><USER32> Why the focus on electric vehicles? Am I wrong in assuming residential energy storage would be a bigger market?

<comment><USER33> In cars having lower weight & volume makes a big difference (your house has more space, and doesn't have to be lugged around). The safety aspect is a big part also - no risk of exploding cars (and already no risk of batteries being pierced when in a house).

</comment></comment><comment><USER34> Even if completely true, that technology will probably come too late for cars. With the current production (and sales) of Tesla, other carmakers have had to react one or two years ago (and it looks like they did).

Expect an increase in the production and sale of EV by a factor of ten in the next five years, barring a global economic crash. That scale should easily drive down the cost of conventional LiIon cells below the cost of gasoline engines (you will probably be paying around 100$/kw/h or even less).

In such a scenario there is not much room to develop and scale a brand new technology. It could be interesting for planes though.

<comment><USER35> Cost isn't the only factor. There's a limit to how much battery you can physically cram into the car. If a new technology can give you 2-3X more range for the same volume of battery, cars made with that will have a competitive advantage. It might be more expensive at first but you do the same thing Tesla did: start with expensive cars and work your way into higher volume.

</comment></comment><comment><USER36> In the past years all articles were talking about breakthrough research. Now they also add the manufacturing term. I think that's a step ahead!

</comment><comment><USER37> This company looks more promising and interesting:

[https://www.bizjournals.com/boston/news/2018/02/07/renault-n...](https://www.bizjournals.com/boston/news/2018/02/07/renault- nissan-mitsubishi-contributes-to-65m-round.html)

</comment><comment><USER38> I'm not familiar enough with the technology to read through the explanation: that article doesn't mention Cobalt, Lithium, Nickel or rarer Earth metal. My understanding of the future of batteries is that, unless we find alternatives to those (or large sources outside of Tibet), we might get into geopolitical troubles.

</comment><comment><USER39> > they close a $20 million series A round of financing

> ...

> Solid Power said that it plans to use the funds from its Series A investment > to "scale-up production via a multi-MWh roll-to-roll facility, which will be > fully constructed and installed by the end of 2018 and fully operational in > 2019."

Is $20M enough for "multi-MWh roll-to-roll facility" ?

</comment><comment><USER40> Check out "NOVA: Search for the Super Battery" on Netflix www.netflix.com/title/80991272?source=android It's a great intro into the challenges of current batteries and it shows Ionic materials' battery which is very similar tech to the one described in this article.

</comment><comment><USER41> A similar product maybe? [https://youtu.be/kJXRyWQgOY4](https://youtu.be/kJXRyWQgOY4) Solid state batteries from ProLogium. I contacted them earlier to for pricing.

</comment><comment><USER42> This specific business model is proven to be worth-the-wait until proven innocent vs. early investing for a hope of windfall that highly likely will never materialize.

There is an excess of VC that reduces quality of due diligence.

</comment><comment><USER43> I'm eagerly looking forward to when I can replace gas tanks with batteries of comparable energy density, and put 400+HP electric motors in unsafe light old driver's cars.

<comment><USER44> That will be a long long time coming. Gasoline is about 46 MJ/KG or 34 MJ/L. The best lithium-metal batteries are about 2 MJ/KG or 5 MJ/L. The best lithium-ion batteries, about half that. Gasoline is extremely energy dense. For a comparison, TNT is only 5 MJ/KG and 7 MJ/L.

<comment><USER45> ICE efficiency brings that down a decent amount, no? 35-40% at best. The fuel is much more dense, but converting it is not as efficient.

<comment><USER46> > ICE efficiency brings that down a decent amount, no?

In terms of power to the wheels, yes. Some of that latent energy can be useful, especially after it's converted into heat.

</comment></comment></comment></comment><comment><USER47> The main red flag is the weak engineering backgrounds of the founders and team in general.

</comment><comment><USER48> Does solid state imply it won't wear out? That alone would be a huge deal.

<comment><USER49> In short. No. Two big issues with current state of the art solid-state batteries are i) the amount of current that the batteries can handle is typically low at least because the conductivity of the solid-state elecrolyte is much less than a typical liquid electrolyte; and ii) cycle life is low at least because small defects in the electrolyte/electrode (cathode and/or anode) interface(s) are not self-healing. In a liquid electrolyte, the liquid can accommodate more changes at the interface because it is liquid.

<comment><USER18> While i and ii might be "typically" true it is not the case for the "current state of the art". See research by the Sakamoto group at umich.

</comment></comment></comment><comment><USER50> > Battery breakthrough

discarded.</comment>


Long Names are Long - <AUTHOR> http://journal.stuffwithstuff.com/2016/06/16/long-names-are-long/ <comment><USER2> I think that the most important thing to understanding about naming is how it interacts with scope. Class names tend to be longer because there is no outer scope (unless you have packages or namespaces). Likewise, single character names are fine in very localized contexts like this:

users.map {|u| "(" \+ u.first_name + ")" }

'u' would be a very bad variable name in a broader context. Here, we can easily see it's a user.

<comment><USER3> "u" is a terrible variable name in that context also.

<comment><USER4> I disagree. It is a great, clear, readable, succinct name, the same way that 'i' is a great name for an index in a loop, or i,j,k can be great names for nested indices. Einstein's multi-index notation was based in the same principles and works great in the contexts where it is used, the same that 'u' works great above.

<comment><USER5> Use 'j' and 'k', avoid 'i', especially for loop controls. It's so much easier to find their uses in the loop body with an editor, since they're high-valued Scrabble letters and they don't show up in C++ reserved words apart from "break".

<comment><USER6> Use an IDE instead of an editor and finding/hilighting usages is just one keypress away. I'm often surprised how many people assume IDE=editor, but with higher system requirements.

<comment><USER7> In Vim (editor, not IDE), if your cursor is on the i, then * will jump to the the next occurrence, # the previous one. In addition, they all get highlighted if ":set hls" (highlight search) is on, which is the default.

"Don't use 'i' because it occurs often in keywords, making it hard to search for" is the most outlandish thing I've head in a good several weeks, even without the Scrabble reference.

<comment><USER8> Alternatively, you could search for "int i" or "\<i\>", or "for (i".

</comment></comment></comment></comment></comment></comment></comment><comment><USER9> Hungarian Notation is not, and was never, for representing the type of a variable. It's about usage of that variable. "c" represents a change, "w" means width, "x" means horizontal position, "ix" is an index into an array. All of them are `int`s, but "cw" "cx" "ix" and "x" are all different kinds of variables.

[http://www.joelonsoftware.com/articles/Wrong.html](http://www.joelonsoftware.com/articles/Wrong.html)

<comment><USER10> Some would say those _should_ be their own types, even if simply aliases to built-in ones.

<comment><USER9> I strongly agree, but nobody* uses languages that would make it a compilation error to add "cw" and "ix" together.

<comment><USER11> Nobody uses C? [https://github.com/torvalds/linux/blob/v4.3/arch/alpha/inclu...](https://github.com/torvalds/linux/blob/v4.3/arch/alpha/include/asm/page.h#L26-L33)

Or C++? [http://www.boost.org/doc/libs/1_60_0/libs/serialization/doc/...](http://www.boost.org/doc/libs/1_60_0/libs/serialization/doc/strong_typedef.html)

(I'd buy "Nobody uses Rust", but I can't resist a "maybe they should.")

</comment></comment></comment></comment><comment><USER12> It's also really useful to add naming conventions that convey how expensive something is. For example:

        myObject() // Returns immediately always
        getMyObject() // Might do some light calculation
        fetchMyObject() // Doh, better cache this!

Names can be extremely useful to convey expected usage as well.

<comment><USER13> MacOS's Core Foundation API has naming conventions related to object ownership: "create"/"copy" = you own the object returned by the function, you have to release it after you're done with it. "get" = you don't own it.

[https://developer.apple.com/library/mac/documentation/CoreFo...](https://developer.apple.com/library/mac/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html)

</comment></comment><comment><USER14> A lot of the time that type names end up in method parameters, it's due to a lack of support of overloading in the language.

In particular, isn't Dart (the language described here) one such language? It's been a while since I used it, and I never wrote much, but I at least _thought_ that was the case.

<comment><USER15> I used to like how overloading lets you call it sort instead of sortRectsByArea but over the years came to the opposite conclusion. Very short and generic names are great for locals or for truly generic functions but generally a function name shouldn't be too generic IMO, both because grep has its uses regardless of IDE support and because it makes it less necessary to look up definitions. mergeTableCells is better than merge even if you know it's passed a list<TableCell> because merge could be merging the cells or the cell contents or who knows what else, and because looking up the type of the argument costs in itself (as it's not always a local declared right near the call and even if it is, the type might not be spelled out in the declaration.)

Also, reusing names through overloading without providing actual polymorphism, either run time or compile time, is IMO bad, as in I don't get what's there to like. If one open function gets a file name and another gets a username and a password, what's so great in that they have the same name?

<comment><USER16> Rather than ``sortRectsByArea`` I'd rather have a generic ``sort`` that supports a Schwartzian transform, like Python's ``sorted(stuff, key=transform)``.

Function or method names that postfix the mode onto the verb, like "parse_from_file", are usually an indication that the design could be improved by creating a consistent interface for the various modes. Sometimes it's better to provide a handful of modes, but I always double-check when I see myself writing names like that.

[0] [https://en.wikipedia.org/wiki/Schwartzian_transform](https://en.wikipedia.org/wiki/Schwartzian_transform) [1] [https://docs.python.org/3/library/functions.html#sorted](https://docs.python.org/3/library/functions.html#sorted)

<comment><USER17> That depends a lot on your actual architecture and domain.

Some times, you need parse_from_file, and nothing else. Other times it's worth parametrizing everything and just assembly generic code at the top level.

</comment></comment></comment></comment><comment><USER18> com.sun.java.swing.plaf.nimbus.InternalFrameInternalFrameTitlePaneInternalFrameTitlePaneMaximizeButtonWindowNotFocusedState

[http://www.javafind.net/gate.jsp?q=/library/36/java6_full_ap...](http://www.javafind.net/gate.jsp?q=/library/36/java6_full_apidocs/com/sun/java/swing/plaf/nimbus/InternalFrameInternalFrameTitlePaneInternalFrameTitlePaneMaximizeButtonWindowNotFocusedState.html)

<comment><USER19> I wonder what the most interesting program you can fit in the number of bytes it takes just to represent this class's name is.

</comment></comment><comment><USER20> > I'm glad we now live in a futuristic utopia where keyboard farts like p, > idxcrpm, and x3 are rare.

Perhaps it's the old "fart" in me, but these seem pretty clear.

p: a throwaway pointer, indicating that I'm probably in a C style for loop over an array.

idxcrpm: and index into crpm. What is 'crpm'? Dunno - what is 'window'?

x3: The third, distinct, x value. I see such variables used frequently in spatial algorithm implementations, where 'x' has distinct meaning.

It's more about knowing the idioms of the code you're in than some overarching rule of law.

<comment><USER21> Code using single letter variable names and abbreviations makes people up to 15% slower at understanding code [1, 2].

Of course it is possible to determine - bottom up - what a variable is supposed to do or that p is short for pointer, it still slows others down because it requires them to perform mental mapping. This effect, of course, depends on experience. If you write your vars like this all the time your penalty won't be as big.

[1] Influence of identifier length and semantics on the comprehensibility of source code, [https://github.com/cessor/bachelor- thesis](https://github.com/cessor/bachelor-thesis)

[2] Much shorter version published in [https://fg- sre.gi.de/fileadmin/gliederungen/fg-sre/wsre2016/...](https://fg- sre.gi.de/fileadmin/gliederungen/fg-sre/wsre2016/WSRE-2016-Proceedings-2.pdf)

<comment><USER22> Upvoted, but I'll add that I'm surprised at how small you found the effect of naming things a,b,c,... with no mnemonics at all. (I skimmed the shorter paper.)

</comment></comment></comment><comment><USER23> Glossed over this but it drives me nuts:

      // Bad:
      String nameString;
      DockableModelessWindow dockableModelessWindow;

See it? _Don 't_ dance around reserved words/used names in a space with _caps_. Arg.

<comment><USER24> As in the following?

var foo = new Foo();

Totally disagree. I find differentiating between definition and instance via caps very intuitive and clear.

</comment></comment><comment><USER25> I agree with much of this on principle, however one of the first examples really strikes me as poorly conceived.

One such example is the variable 'name'; there are a lot of other languages and contexts in which 'name' can be a reserved keyword. As a member on an object it's probably OK, but in a larger syntax it isn't quite precise enough. A better variable might be nameDisplay.

This presumes that you are referring to the way that a user prefers their name to be displayed in native output; it does not attempt to make any distinction to name components which may or may not be applicable.

</comment><comment><USER26> I struggle with naming things, especially in python where we dont have explicit types,i do end up with the "strawberryList" kinds of names.

I work in NLP / machine learning and a lot of us are not first and foremost programmers. It can be hard to come by good code in terms of coding style and naming, so I'll ask here if anybody has good examples or even know of any guides (even little things like a consensus on calling it "targets", "y", "labels" or "gold" would be nice)

<comment><USER8> PEP8 is a good start, in case you're unaware of it. It contains a bunch of style guidelines for python, including some naming conventions.

</comment></comment><comment><USER27> > It needs to be clear: you need to know what the name refers to.

> It needs to be precise: you need to know what it does not refer to.

Is there such a generally accepted distinction between the meanings of "clear" and "precise"?

</comment><comment><USER24> The fact that this is an issue at Google makes me think this is entirely the result of the review process rewarding it. Could they really hire so many highly qualified people with no sense of DRY?

</comment><comment><USER28> Long variable names have some fatigue associated, but when I'm hacking on 20,000+ line files, those long names really save similar things from being blurred.

</comment><comment><USER29> > June 2016

> Dart usage inside Google is cranking up

o_0

</comment><comment><USER30> I am amazed at the number of people who use single letter variable names.

It's almost always better to use a double letter: uu, kk, ii, jj.

It's one of the few code patterns that most people will adopt without even discussing it once they see it.

<comment><USER31> How is it better? (This is a literal, non-rhetorical question, not a joke about even discussing it.)

<comment><USER30> Finding it in a sea of text.

Try searching for all the instances of variable "u" or "i" in a file.

Syntax-aware IDE's fail often enough that I have to rely on "search-and- destroy" far more often than I would prefer.

<comment><USER32> vim: /\<i\>/

Actually, if your cursor is on the variable "i", just pressing * or # will do the trick. I'm pretty sure other editors have similar functions.

If you really want double-letter names, :%s/\\(\<[a-z]\>\\)/\1\1/g would probably do the trick (well, except that every occurrence of "a" in a comment will become "aa": how to avoid it is left as exercise).

<comment> squeaky-clean Just tested it in some different editors with some javascript because I care way too much about editors or something.

Sublime Text 3 captures the independent 'i' correctly. Though it also picks it up in comments and strings.

VS Code incorrectly highlighted all instances of the character 'i', even if it was part of another symbol. "Change All Occurrences" affected all instances of the character 'i'.

Atom doesn't appear to have this feature without plugins (though someone should correct me if I'm wrong).

IntelliJ and it's variants handled it perfectly, even understanding the actual variable, rather than just the symbol. "Rename All" would ask if I wanted to affect strings and comments, or just code (if there was an ' i ' in a string or comment, otherwise it wouldn't prompt), and it would only rename the variable within the correct scope. I tried it with both var and let.

I would try more, but I think I'm wasting too much time, haha. But moreover, like others are saying, I can't think of a time where I've ever actually wanted to do that. Renaming all instances of a single letter variable? Generally the single letter is a very common convention I wouldn't change (i,j,k, u, x,y, _), or is in a very small, uncomplicated function where I wouldn't need a text editor's help to rename it because it only occurs once or twice. Anything more advanced than that gets a more verbose name that any of these editors could easily ctrl+F.</comment></comment></comment></comment></comment>


Ask HN: Is There a LeetCode for Refactoring? - <AUTHOR> I'm looking for some samples of realistic messy code (preferably with some sample well-refactored solutions) so I can practice refactoring legacy code, applying functional programming principles, etc. Anyone know of a resource for something like this? <comment><USER2> Most code bases in most companies.

</comment><comment><USER3> I don't have a full 'LeetCode' style example, but the Gilded Rose Kata teaches me something every time I try it.

Original Kata: [https://iamnotmyself.com/2011/02/14/refactor-this-the- gilded...](https://iamnotmyself.com/2011/02/14/refactor-this-the-gilded-rose- kata/) Sandi Metz's Take: [https://www.youtube.com/watch?v=8bZh5LMaSmE](https://www.youtube.com/watch?v=8bZh5LMaSmE)

</comment><comment><USER4> If having the solutions is not a must, you could take a dive in trending oss repos. ([https://github.com/trending](https://github.com/trending))

I'd say to look for high coverage pieces, so that you prove your refactor is not breaking things.

Then ask for code review, maybe in something like [https://codereview.stackexchange.com/](https://codereview.stackexchange.com/)

</comment><comment><USER5> Your own code from 6 months ago usually works.

</comment><comment><USER6> I was thinking about this a couple of weeks ago. The difference would be in the format. I am considering creating a repo with refactoring katas. The most difficult part is to come up with examples that show up in real codebases.

</comment><comment><USER7> there isn't a single way to refactor code, code can be refactored in many different directions to pursue many different objectives.

Here's a few arbitrary ideas:

* Scrape_it is an arbitrary python project that shows up in google search for "pypi scrape" [1]. Looking at the code, it doesn't appear to have any automated tests. Goal: write a single unit test for the example of usage shown in the readme. The unit test should work without any dependency on : network access to remote websites or other services running locally, the current time, data files in the filesystem. Refactor by making minimal safe changes to the code as/if required in order to write a unit test.

* scipy's vendored copy of the useful L-BFGS-B optimisation algorithm [2] has a bunch of calls to a timer(ttime) subroutine, but the timer(ttime) subroutine was patched so it doesn't do anything. But there's still many calls to timer(ttime) throughout the lbfgsb.f code. Goal: simplify the code by identifying if any remaining variables and code related to cpu timing within lbfgsb.f can be safely removed without changing the behaviour of the algorithm. If it can be safely removed, remove it. Tricky: demonstrate with some degree of confidence that your change is safe and doesn't break behaviour!

* fixCache, featured on HN a few days ago [3], includes a rule to decide if a git commit is a "fix commit" based on user-supplied keyboards identified in the commit message. Goal: modify fixCache to make this functionality more flexible, so a user can still configure fixCache to use the current behaviour, but can also optionally configure fixCache to call a custom user-defined javascript function that can decide if a commit is a "fix commit" or not using all information available about the commit (e.g. which files were touched, the contents of the changes to those files, etc) instead of a list of keywords. Refactor as/if necessary to implement this feature.

Further reading: [https://testing.googleblog.com/2008/07/how-to- write-3v1l-unt...](https://testing.googleblog.com/2008/07/how-to- write-3v1l-untestable-code.html) , Michael Feathers' book "working effectively with legacy code": [https://ptgmedia.pearsoncmg.com/images/9780131177055/samplep...](https://ptgmedia.pearsoncmg.com/images/9780131177055/samplepages/0131177052.pdf)

[1] [https://pypi.org/project/scrape-it/](https://pypi.org/project/scrape-it/) [2] [https://github.com/scipy/scipy/tree/f865e9ed01be30c52f2b3841...](https://github.com/scipy/scipy/tree/f865e9ed01be30c52f2b3841795aa2d8f5fa3d86/scipy/optimize/lbfgsb_src) [3] [https://github.com/aavshr/fixCache](https://github.com/aavshr/fixCache)</comment>


Destroying happiness - <AUTHOR> http://sethgodin.typepad.com/seths_blog/2008/08/destroying-happ.html <comment><USER2> Any happiness related to interpersonal human relationships have not likely changed much over time.

Did Hamlet's unhappiness have anything to do with his standard of living?

If someone asked me why people today aren't happier, then, after pointing out the hidden presumption that is at best a huge oversimplification and at worst completely wrong (are "people" _really_ not any happier now than in 17th century France?), I'd say it's probably because people are still selfish and cruel to each other.

</comment><comment><USER3> I predict that if Obama wins, happiness will increase.

Why? Because the current "things are horrible" news reporting will be replaced by "things are getting better" even if said things don't change at all.

We saw this at the beginning of Clinton's first term. "We're in a recession" became "we're in a recovery" after Clinton took office even though the recovery started well before said election.

</comment><comment><USER4> I'm curious how journalist measure happiness over time. Especially how they assess the happiness of people who lived in a time before social anthropologists to study the well-being of a society.

</comment><comment><USER5> Good insight. Surprisingly deep when you start thinking: it shows that sometimes marketing becomes a negative-sum game due to externalities. Will it lead Seth to question his career choice?

<comment><USER6> He said that marketers that focus on _maintaining_ market share remind us that we are happy.

He proposes to focus on maintaining a market share, in the long tail, instead of mass marketing and making everybody unhappy unless they have the last piece of fancy crap.

<comment><USER5> What proportion of ads you see are for things you already use? It doesn't balance out. I guess most things are not used by more than 50% of the ad's audience.

<comment><USER6> Obviously you don't usually read Seth Godin. He is against advertisement as we know it. Marketing is more than advertisement. Take a look at his main posts and his Wikipedia page.</comment></comment></comment></comment>


Unprecedented Arctic megafires are releasing an amount of CO2 - sahin-boydas https://www.newscientist.com/article/2208610-unprecedented-arctic-megafires-are-releasing-a-huge-amount-of-co2/ <comment><AUTHOR> I guess "The billions of tons of peat under the permafrost catching fire" was one of the end-game scenarios from climate change that none of us predicted.

C'est la ~~vie~~ mort.

<comment><USER2> That would make a great apocalypse movie.

</comment></comment><comment><USER3> Original title is "a huge amount", current title "an amount" doesn't convey any information.</comment>


Pumping Station 1: A workspace for nerds, geeks, and artists [video] - <AUTHOR> http://www.windycitizen.com/chicago/scitech/2010/06/07/pumping-station-one-video-cooperative-workspace-nerds-geeks-artists

<comment><AUTHOR> Pumping Station One on Twitter: <http://twitter.com/pumpingstation1>

Pumping Station One on the web: <http://pumpingstationone.org/>

</comment><comment><USER2> We need one of these in the boston area, or are there any im not aware of?

<comment><USER2> nvm i just found a good list of places around <http://hackerspaces.org/wiki/List_of_Hacker_Spaces>

<comment><USER2> the only thing that really comes close is the artisan asylum @ artisansasylum.com</comment></comment></comment>


Show HN: Crash reporting for every developer and every programming language - <AUTHOR> https://critimon.com <comment><AUTHOR> Hi, I've recently released a new version of CritiMon. For those that don't know, its a new crash and error reporting service, which works on every platform and every programming language. There's many official libraries ranging from C++, PHP, Javascript and Android to name a few, and for any platforms/languages not officially available there is a simple API to send crashes from your own custom made library.

CritiMon is focussed on providing a simple, lightweight and affordable crash monitoring primarily aimed at solo developers and/or startups.

There is a free plan available, as well as paid plans, and currently all paid plans have a 50% off on the lifetime of your subscription.

If you have any questions or suggestions, then please drop me an email at chris[at]boardiesitsolutions.com.

Thanks Chris</comment>


Artificial intelligence, facial recognition and bees - <AUTHOR> http://aurmoth.blogspot.com/2009/01/artificial-intelligence-facial.html

<comment><AUTHOR> Clearly I need a tame Bee (probably several) - I am effectively face blind - <USER2> do not seem to be able to store facial characteristics in a way that makes that store useful for recognising people - I use alternate information (some of it visual) to identify individuals - making meeting people I know in the "wrong" location problematic - but you learn to cover things up during the time it takes to identify someone you know well.

</comment><comment><USER3> Link to the research article: [http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...](http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004086)</comment>


Smart TVs sending sensitive user data to Netflix and Facebook - <AUTHOR> https://www.ft.com/content/23ab2f68-d957-11e9-8f9b-77216ebe1f17 <comment><USER2> This is a pretty open secret within the industry. Geographic data can be provided via setup (a lot of TV's ask for a zip code on setup) or usually simply via GeoIP lookup.

Dig a bit deeper and you get into service provided by Samba TV and or Inscape and you can find that they're sending back frames of video in a lot of cases to track what you're watching.

This data is becoming a huge mechanism for subsidizing TV sales and the interactivity is being looked at as a huge opportunity to recoup some of the ad spend being lost via streaming and fewer 30 second spots.

With new TV's its time to view them as private as a browser (With less controls).

[https://samba.tv/](https://samba.tv/) [https://www.inscape.tv/](https://www.inscape.tv/)

<comment><USER3> Roku enabled TVs very clearly send back frames of what you are watching. I've been watching YouTube casted via chromecast plugged into HDMI (NOT the built in chromecast, I have verified multiple times) and the Roku will give me a full width toast saying to press `*` to watch the full movie or some similar contextual option

I was pretty put off the first time this happened. That said, I don't even know if I looked through the settings to see if I could turn it off..

<comment><USER4> I worked on that.

It sends audio and/or video fingerprints (not frames, for privacy and bandwidth reasons), which are matched against a fingerprint database. Whatever people see on TV is usually 10 to 60 seconds behind the _real_ live stream at the broadcaster (which is where the reference fingerprinting happens). GeoIP data can be used to roughly deduce where the TV is located, in order to better filter out false positives out of multiple matches (e.g. in the US where lots of programming on east/west side is just shifted by ~3 hours due to time difference).

<comment> move-on-by Any way to turn it off? Or perhaps block a specific domain via pihole?

<comment><USER5> Don't let your TV access the internet at all.

Smart TV interfaces are almost uniformly worse than set top boxes (one or more of: bad UI, slow CPU, weird quirks, few updates) so you should avoid it anyway.

The current Apple TV (which I cite only because of familiarity) has a great UI, every major app, and robust HDMI-CEC support so you might never have to touch your TV's remote again.

And Apple respects your privacy.

<comment><USER6> Some smart TVs will join open networks if you don't give them one. And I expect that if 5G works as advertised you'll see surveillance capitalism adding 5G connectivity so you no longer have control over connectivity.

<comment><USER5> A website that catalogued the misbehaviours of the various smart TV operating systems (and the easiest methods of defeat) would be handy here.

E.g. Some TVs will honor wifi off setting. Or alternatively setting the TV to use the Ethernet port.

Or if it needs something on the other end, set up old underclocked Raspberry Pi as a basic router/DHCP server that connects to nothing; power it with TV's USB port.

If you've got a fancy router, connect it to your network with a fixed IP and firewall deny all packets from/to its IP.

If you've got a fancy AP, set up an alternative SSID that connects to an unused VLAN or otherwise routes to nowhere.

<comment><USER7> A Pi-Hole is good to have in every household. Takes minutes to set up and makes sure that queries to unwanted domains end up in the land of /dev/null

<comment><USER5> A pi-hole only works against adversaries that rely upon DNS, or haven't been coded to connect directly to "trusted" public DNS servers.

(I'm almost astonished that advertising networks haven't switched to using raw IP addresses everywhere.)

<comment><USER8> You could probably very easily make a list of the "evil" IP addresses if that happened

<comment><USER9> You can combine approaches of course. My main in-home DNS, per the DHCP settings on the wi-fi, is a Pi-Hole. Secondary DNS is the pfSense firewall, so nothing's dead in the water if the Raspberry Pi falls over for some reason.

The firewall has the same DNS block-lists as the Pi-Hole, but also has subscription lists of IPs to avoid. Most of those are spammers or malware, but can include whatever other category of malfeasance you desire.

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER10> I disabled WiFi on my Samsung TV after they were injecting ads into the home screen. Spend $800 to get ads served in their shitty/slow UI.

<comment><USER11> An acquaintance attempted that with Kindle, by keeping it in flight mode. After some days it popped up a message kindly asking to give it some network access. After a few more days it simply ignored the flight mode and connected to get fresh ads.

Edit: I've checked with my wife who has an ad supported Kindle for over a year and keeps it in flight mode for months at a time. It never did that to her. So either Amazon changed that a long time ago, or I've believed a lie.

<comment><USER12> I had the same thing happen. I rooted my Kindle and kept it in flight mode to avoid tracking and updates. After not using it for months I recharged it and when I turned it on it had auto updated to the latest version, killing root.

So not only did mine exit flight mode it somehow re-enabled updates and updated itself.

<comment><USER13> It's possible that it may have cleared its settings after being away from power for that long.

<comment><USER12> It shouldn't since settings aren't stored in volatile memory.

</comment></comment></comment></comment></comment><comment><USER14> I tried to never connect my Smart TV to anything, but I realized one day (when someone's stuff was playing on it without me accepting any request...) it connected an open network in my residence. The only trick that worked to prevent it from connecting was putting the wrong password, and let it loop forever, trying to connect. Ugly.

<comment><USER15> I have an extra SSID which has no internet access and logs all of the things for exactly this reason.

<comment><USER16> What's the simple setup for something like this?

<comment><USER17> Ubiqti makes it really simple

Basically create a new hidden ssid and make a new rout that goes nowhere

Then enter SSID and password into the tv

You can monitor that interface too

<comment><USER15> For bonus points, mirror the traffic off to a zeek to get even more than the ubiquiti DPI

</comment></comment></comment></comment></comment><comment><USER18> It is not clear why we should necessarily be suspicious of smart TVs based on the findings here.

The lines seem to be blurred between what data is being sent _by the TV OS itself_ versus a third party app that someone may have decided to use during the period that the researchers watched outbound network connections.

If someone is using the Netflix app, this necessitates that the TV must communicate with Netflix. How else would it work? Similarly, if you use the YouTube app, you would definitely get some requests to Google. Surely some developers of smart TV apps have decided to use Mixpanel or Adobe for analytics.

The "sensitive user data" alluded to in the headline is later admitted to be, at a minimum, "information about the device people are using, their locations, and possibly even when they are interacting with it".

Let's unpack that. It's pretty common for every web browser to send a user agent. Why shouldn't apps for a TV send device info to the app maker? Location can be inferred via IP, like any network request (nothing special here). And with any request, you of course know the time it was made (and could infer the interaction that produced it, like opening the app).

So they've told us nothing to support the headline. Indeed, the original paper from Northeastern notes that they did not try to inspect the data or MITM encrypted connections, so all we know is that requests are being made to these services during the course of operating the device and its apps. Not that the device manufacturer itself is sending your data, unprompted, to these third parties. So, the headline does not match the story.

Seems like university PR office must have gone a little crazy with this one. Why is nobody on HN questioning such a sensationalist, substanceless article?

<comment><USER19> Because it interferes with the idea of a TV being a display. A TV should not have apps. If it does have apps, these apps should not communicate data to the manufacturer. It shouldn't send back data about the operating system because a TV shouldn't have an operating system.

<comment><USER20> Of course a TV should have an operating system. It needs menu's and options, video and audio codecs, up and downscaling algorithms and many many other things, just to be a dumb TV.

<comment><USER21> All of those codecs and video processing are probably done in hardware regardless of whether it has a real OS or just a microcontroller.

</comment></comment></comment></comment><comment><USER22> I would love to update my 10 year old 1080p Philips non-smart TV to a 55" or so 4K HDR screen but I don't want any of the smart features. Does anyone know of any manufacturers selling high end "dumb" TVs?

For now I'm comfortable using my appleTV but I like the fact that I can disconnect it at any time. I want a TV that will simply display whatever signal it receives without any connectivity required.

<comment><USER23> I'm using an LG OLED TV (2018 model I think) with an Apple TV, and it's working pretty much exactly like a dumb screen. I haven't connected the TV to the network, and I control everything with the Apple TV remote - it turns on the TV via HDMI CEC as needed, and when I turn off the Apple TV the TV turns off too. I've also connected my home theater system via HDMI ARC to get better sound, and CEC turns on and off the speakers too.

All I see of the LG interface during normal use is a small box in the top right corner that says "Apple TV" on boot and "Denon available" or something like that when the speaker systems has booted.

Also, the screen turns on quickly so there's practically no waiting for anything.

I was thinking of getting one of those in-store displays instead of a TV, but they don't usually have HDR.

A++++, would buy again!

<comment><USER8> I'm using a Raspi4 with Libreelec (this is kodi) and I have had pretty much a similar experience (but with a bunch of OSS quirks of course). A nice surprise is that I can actually control the kodi interface with my TV remote

</comment></comment></comment><comment><USER24> One of the first images to appear on my Samsung TV, after purchasing and plugging it in to the power outlet, was a prompt asking to connect to my WiFi.

They almost got me, but thankfully there was an option to skip that step. But I'm sure they'd hook my parents and friends for sure.

<comment><USER25> Next time, make a VLAN with its own Wifi, then connect the TV to that VLAN and then what you want to do is block any incoming or outgoing network traffic to the smart TV. If you do this then no one else can attempt to hijack or connect to your TV and the TV wont ask you to connect it to a network, because its already connected to a network. This worked great on my LG smart TV.

<comment><USER26> What is the point of doing this as opposed to just skipping that step? Does it keep nagging you? Or are certain features disabled if you don't connect?

<comment><USER27> I don't own a Smart TV, but without this step I'd be very suspicious that the TV would silently try to connect to open wifi networks, or perhaps some kind of hotspot like xfinity or AT&T that the manufacturer made an agreement with.

<comment><USER11> Won't they just use Ethernet over HDMI?

<comment><USER28> Oh FFS I just learned this was a thing, I can't even trust my cables anymore.

<comment><USER29> Be aware that your ethernet cables could also be powering stuff, so that's another cable to watch out for ;)

<comment><USER30> Watch out for the reverse too, ethernet over powerline is a thing!

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER31> > Smart TVs sending sensitive user data to Netflix and Facebook

No way! Has that ever been news? It is the first thing that comes to mind when some product 'needs' to be connected to the internet. Sending private data is most likely the only reason a internet connection can be made with the device. All the 'great' software around it is only fluff supporting to lure people sending their private data unknowingly. Do they send microphone and camera data home? Of course, that's the cream. Oh, and do they protect your sensitive data well? Nah, that's not a priority, who cares..

In the past you bought a new tv, and the manufacturer was happy and treated you with respect. Today you think you buy a tv, but tv is actually the secondary feature, you just bought an intrusion device that collects your private life in order to send it to the manufacturer for selling it.

I have a new x-large smart tv which I would never connect to the internet for these reasons. I use a dedicated pc with a good graphics card that connects through HDMI. On my couch I have a wireless mouse and keyboard. With this dead simple setup I cannot only watch regular tv, I can of course do anything you can think of doing on a pc. It also has become my favorite gaming setup.

I think governments should be more active to protect citizens of course. Non- technical people are prey nowadays. I despise this new economy and I'll never ever want to make any money of of it, I'd rather live and die poor.

<comment><USER32> The problem is that I want to just use the netflix built-into the TV. Firing up a separate device just to watch something seems like a waste of energy to me, and then I probably need a separate controller for it(like, I can control the PS4 with my TV remote, but I cannot switch it on remotely without using the DS4).

>>I have a new x-large smart tv which I would never connect to the internet for these reasons. I use a dedicated pc with a good graphics card that connects through HDMI.

Assuming you use windows on it, haven't you just traded one type of telemetry for the other?

<comment><USER31> No. It's a linux, and there is no mic or cam connected. I use Netflix too, works like a charm. And I can understand your temptation of using the Netflix button on the remote control, it's one of the lures.

</comment></comment></comment><comment><USER33> When can I buy a TV without smart features? I don't doubt that my smart TV is reporting some data about my usage, but I barely have a choice in the matter.

<comment><USER34> It's surprising to me that you can't find a single medium or high-ish end TV without smart features, but at the same time chromecast/firetv/apple tv units and sticks also seem to be selling very well.

Is everyone just putting up with the shitty built-in smart interface, but then switching inputs to their separate unit of choice?

<comment><USER35> I really wish the whole home theater system was way more modular. I want:

1\. A TV that _just_ displays video from an HDMI input.

2\. An A/V amplifier that _just_ receives an HDMI A/V signal from a single input, passes the video from that to to the TV, and does Dolby/DTS/whatever decoding of the audio, amplifies the result, and sends it to my speakers.

3\. An HDMI switch that I can plug assorted A/V source into (FireTV, Roku, OTA TV tuner, Blu-ray player, Cable box, etc) into, which I'll connect to the A/V receiver.

(Actually, what I really want is for the switch to split the A/V signal into separate audio and video on two different HDMI ports. Video goes to the TV, audio the A/V amplifier--except now it is just an A amplifier. But I think there may be licensing restrictions on that kind of splitting that make it so you can only split at the step that converts to analog for the speakers).

All of the HDMI connections should support Ethernet over HDMI.

None of these should have WiFi built-in. They networking should be via Ethernet. If I want WiFi, I'll add a WiFi access point to the home theater LAN.

I'm not sure how Ethernet over HDMI interacts with HDMI switches. If you have, say, a 4 input, 1 output HDMI switch, does that switch all signals, so that you only have Ethernet between the one selected input and the output, or are the Ethernet lines treated specially and connected like a hub, so that all devices on both sides of the switch can communicated over Ethernet, regardless of which input is currently selected for A/V?

If the later, then the home theater LAN can use the HDMI ports. If the former, then all the devices need an Ethernet port.

<comment><USER36> You basically want to be looking at projectors, they meet all your requirements, and they're not generally "smart".

</comment></comment></comment></comment><comment><USER37> Kind of off topic, but I have an older Samsung smart tv. It has an ethernet connection, but it didn't have any option for WiFi. For a few years I had it wired up to ethernet, and after rearranging where my router lived in the house I didn't have a long enough ethernet cable, so I hooked up a USB WiFi dongle. It worked great for a few months until I needed that dongle to connect a Raspberry Pi to WiFi, so I stole it from the TV...and lo and behold the TV still had internet access via WiFi! The only thing that I think could have happened is that the TV had WiFi hardware but was disabled in software, because at the time a WiFi TV was selling at a premium and this was a cheapo one I bought from Wal-Mart. So I guess hooking up the USB dongle somehow unlocked it. It kinda freaked me out that there was hidden WiFi hardware in there.

 _edit_

The tv definitely phones home too, my Pi Hole blocks a few hundred attempts to lookup log-ingestion.samsungacr.com, xpu.samsungelectronics.com and upu.samsungelectronics.com _per day_.

</comment><comment><USER38> This is why I (currently) trust Apple, because they appear to care about privacy. I am not blinding myself to the possibility that this may change, but right now this is their selling poin tto me.

<comment><USER39> Apple cares about privacy enough to make Google their default search provider for many billions each year. Apple pays lip service to your privacy and obviously cares more about money just like any other corporation.

<comment><USER40> You can make DuckDuckGo your default search engine on all Apple devices.

Apple is definitely a for profit business and they charge for their products instead of subsidizing with data aggregation or theft.

<comment><USER41> Still doesn't change the fact that if Apple was principled on privacy, they would refuse google's billions in spy money and wouldn't, by default, send their customers to Google search engine to be harvested

<comment><USER40> I hear ya but if DDG doubled googles offer Apple would change the default. They are for profit and don't hide it. Google and Facebook on the other hand hide or at least try to hide their illegal business models

<comment><USER42> It is not their fault the highest bidder is the shadiest of them all? That is some weird mental gymnastics to give Apple some moral high ground.

</comment></comment></comment></comment></comment></comment><comment><USER43> Just wait for TVs and other gadgets with built in 5g and iot sim cards that you can't simply "skip network" on.

<comment><USER44> I was shocked when a medical device I got had a built-in CDMA modem to send telemetry to my insurance company. Thankfully there's an airplane mode.

<comment><USER45> Patient appears to not be using device, increase rates accordingly.

<comment><USER44> That's pretty much what it's for! If you don't use the modem, you need to export usage data onto an SD card and mail it in.

Conceptually, I understand that they don't want to continue paying for a therapy if you're not actually using the equipment. But having a wireless modem built-in is a bridge too far.

</comment></comment></comment></comment><comment><USER46> My TV (Vizio P55-C1) doesn't have a "disconnect" option. I either need to do a factory reset, or change passwords three times (WiFi AP to temporary, TV to temporary, WiFi AP back to normal.)

I suppose I could just never connect it to WiFi, but then it wouldn't get firmware updates.

<comment><USER47> TVs should be dumb enough to never need firmware updates. I realize many do, but I consider that a design flaw.

</comment></comment><comment><USER48> I still don't understand this whole "business model". Could someone ELI5 these three questions?

1) How exactly is this targeting information useful to advertisers? Do they pay for targeting in order to pay for fewer ads?

2) Where is the market for "user data"? How do you sell your blog visitor's data?

3) How much is the data worth? Some equivalent to CPM? Could you monetize your blog not by showing ads but by selling user information?

<comment><USER49> >Do they pay for targeting in order to pay for fewer ads?

Yes. There can be more and smaller advertisers when you can tailor ads to the market. Nontargeted advertising is economic only for biggest brands.

Data that is collected sparsely can help to identify interests and match ads to users. Geographic location helps to match adds from your local market to the blog the user is currently reading, for example.

Continuously collected information can be used to direct and predict behavior. The user matches profile of stressed person. People under stress have low impulse control, show them ads for products that are typical impulse purchases. S

>Where is the market for "user data"? How do you sell your blog visitor's data?

You don't. You add common trackers to your site and receive income from ads trough them.

> Could you monetize your blog not by showing ads but by selling user > information?

No. This does not work in small scale. Single blogger can't create much value by selling data directly. Google or Facebook do that.

</comment></comment><comment><USER50> I couldn't find info in the article about the whether LG (WebOS) Smart TV's still do this even if you opt-out of all the "Channel Plus" and other sketchy advertising/user-tracking features in the menu.

I guess it's time to fire up Wireshark. I love these TV's because they can be integrated with home automation like Home Assistant. But maybe it's time to put it on a VLAN with no access to the WAN.

</comment><comment><USER51> PSA: If you mostly like to watch movies and/or cinematic TV (with the lights off, or in a dimly lit room), consider a home theater projector instead of a TV. In a dark room (even with white walls) the image is fanatic in cinema mode, and nearly as good (and quite a bit brighter) in "living room" mode. Best of all, they have absolutely zero "smart" features.

I bought an Epson PowerLite Home Cinema 8345 Projector refurbished for around $470 a couple years ago to replace my 720p Panasonic AX200U. The Epsons have a solid warranty and will easily project a 100"\+ image in a dark room on a basic (<$200) screen. The bulbs work out to about 10 cents/hour of usage.

This 3100 is basically the newer (and better) version of mine for $684, and the one I'd get if I was buying today. [https://epson.com/Clearance- Center/Home-Entertainment/Home-C...](https://epson.com/Clearance-Center/Home- Entertainment/Home-Cinema-3100-Full-HD-1080p-3LCD-Projector--- Refurbished/p/V11H800020-N)

</comment><comment><USER52> [http://archive.is/vB4XC](http://archive.is/vB4XC)

</comment><comment><USER53> Did anybody really believe that data wasn't being sent to ad companies like Facebook? Our default position should be to assume it is so until it is proven otherwise.

</comment><comment><USER54> I wouldn't be that hard to make a small firewall to put in between the TV and the Internet, with rules that block unwanted traffic - or better, block it and inject fake data - while allowing normal use of the TV.

This cheap SBC comes to mind, there's a very similar one from OrangePI too. [https://www.friendlyarm.com/index.php?route=product/product&...](https://www.friendlyarm.com/index.php?route=product/product&product_id=248)

It would be nice having say a version for traveling with laptops etc if we don't trust the hotel connection and one to protect from being spied by the SmartTVs, where changing from one to the other requires nothing more than swapping an SD and reboot.

<comment><USER55> How will it detect unwanted (spying) traffic from legitimate operations (software update...)? Moreover it is a moving target, as the firmware can, at some point in time, use another endpoint (especially after an update).

<comment><USER54> "How will it detect unwanted (spying) traffic from legitimate operations (software update...)?"

That would be harder, especially true in case of encrypted traffic.

"Moreover it is a moving target, as the firmware can, at some point in time, use another endpoint (especially after an update)."

This one might be easier to fight than the former. Upgradabe black lists might be a solution, not unlike some antispam software work: the firewall software downloads weekly/daily from a central server (1) a list of all legit/evil addresses and checks where the TV attempts to connect against that list, then filters traffic as required.

(1) I would assume we would trust a centralized server for this purpose as much as we would trust a server holding spam and malware sites.

<comment><USER55> Each firmware update may come with a large list of endpoints. They also may use the very same servers (IP addresses) in order to spy and also for the updates or legitimate apps.

For the customer eager to benefit from a connection to the Internet it may be a lost battle, he will be spied on.

</comment></comment></comment></comment><comment><USER56> You can make a Smart TV into a dumb TV by simply not allowing it to connect to the Internet, ever.

<comment><USER27> In a hn thread the other day, someone told me their TV will simply connect to any open wifi networks it comes across, just to phone home. I couldn't get the brand or model out of them, though.

<comment><USER56> That's awful. We need to find out that brand.

<comment><USER27> Well, there's another guy now saying the same thing in this thread, too: [https://news.ycombinator.com/item?id=21010777](https://news.ycombinator.com/item?id=21010777)

Also on this thread is the supposition that eventually TVs will just have their own cellular data connections: [https://news.ycombinator.com/item?id=21010790](https://news.ycombinator.com/item?id=21010790)

Sickening, really.

</comment></comment></comment></comment><comment><USER57> (I'm asking because I don't know. It's not advocacy. I have NONE of this equipment currently.) So, if I get gigabit cable internet and want to buy a 4K tv and plug it in for streaming Netflix, Amazon Prime, YouTube, etc. (no broadcast, no WiFi to reduce bandwidth), is the solution to leave the WiFi off on TV setup (or give it a bad password to avoid opportunistic connection) and to plug the ethernet cable coming out of the cable modem into an Apple TV and/or Roku instead of into the TV, getting all of my programming thru wires coming out of these secondary boxes?

<comment><USER58> Generally yes. In my (accidental) experience, don't give it a bad WiFi key, it'll just complain. Just leave it disconnected. Honestly, given the unnecessary updates, ads, and just horrid UI that WiFi brought me on my TV, I'd suggest leaving it offline even if you don't care about the privacy issues.

Oh, and WiFi won't change how much bandwidth you're using. And given the low (compared to Bluray) bitrate of 4k content on the streaming services, you probably don't need gigabit.

And, it's not for everyone, but I personally like just hooking up a small PC (Intel's NUC works well here) and using that instead of AppleTV or Roku.

</comment></comment><comment><USER59> Does this happen with Chromecast as well? I'm totally fine with disconnecting my tv since I only use it via Chromecast anyways. Smart tv makes no sense to me simce they are all 10x shittier than Chromecast

<comment><USER60> The spying is one thing, but you're right: SmartTVs doesn't make sense, because the software sucks.

If Sony, Phillips or some other manufacture made a SmartTV with software that rivalled the AppleTV, or even just a Chromecast, then it would make some sense to save the money from the AppleTV and buy a better TV.

The thing is that all of the SmartTVs I tried are slow and confusing. You're better off buying a cheaper TV and getting the $200 AppleTV HD.

If you factor in the cost of developing shitty software, then maybe there would be more profit in just release a new dumb TV.

</comment></comment><comment><USER61> I am really baffled that anyone with a clue would enable "smart" behavior from a consumer electronics product like a TV (ie, one from a company not known for privacy and security).

Our TV is old enough that it's not smart. We mostly watch things from the AppleTV on it, plus some from our very small cable package/DVR.

Choosing a set-top-box vendor you trust (and for us, that's Apple) gives you everything you'd get by trusting Samsung or Vizio, right? What even turn ON the network features of the TV?

</comment><comment><USER62> Ex-spotifier here. I'm only somewhat familiar with this, it's been a while, and I'm not speaking for Spotify, but I wouldn't be surprised if the data is being sent for speaker/remote control device discovery. It's probably the same for Google and Chromecast.

Knowing what else gets collected online, this isn't a big concern for me. I'm more worried about these devices not having great security and not getting security updates for their entire life.

</comment><comment><USER63> My LG C8, which I've done anything on with apps aside from installing Amazon, Youtube and Netflix (which I hope are "safe" and "reputable") is frequently trying to connect out with what appears to be a rootkit in Googling:

> Threat Management Alert 1: A Network Trojan was Detected. Signature ET > MALWARE Misspelled Mozilla User-Agent (Mozila). From: 192.168.1.x:46372, to: > 22.214.171.124:80, protocol: TCP

My firewall picks this up, otherwise I'd never know it.

<comment><USER15> That's a really loose signature, it's just a misspelling which is actually pretty common in low-qa software that talks to the internet.

The dst IP in your alert is an akamai one according to centralops.

</comment></comment><comment><USER64> I've had great luck blocking SmartTVs with a PiHole and a custom list. Also adding regex blacklists like "samsungtv" and "roku" seems to help. Granted, I sometimes disable to block to install updates and apps - but it seems to work. My next move is to start whitelisting destination IPs for smart devices and putting them on their own SSID/VLAN.

<comment><USER65> In-application DNS resolution (e.g., DoH aka DNS over HTTPS) will defeat a PiHole. Will anyone bother

</comment></comment><comment><USER66> I will never buy a "smart TV". For one thing, I don't have much use for any TV. What I have is a large display attached to a media server. It doesn't have Internet access, except when I need to update packages. If there's something that I want to watch on it, I just use a DVD, or get a copy of the file.

</comment><comment><USER67> I every now and then I have to have this conversation with my mum and dad: "the TV will occasionally ask you to tell it your name, where you live, your birthday etc. Don't tell it ANYTHING. They can't make you."

I wish the people who make my parents' TV would stop trying to trick them into doxing themselves.

</comment><comment><USER68> Which is why I have firewall rules _inside_ my freakin' house which prevent things from sending packets outside. It really is annoying. If you allow DNS and ping it seems the TV won't constantly complain that it doesn't have an internet connection.

</comment><comment><USER69> Does anyone publish a set of firewall rules (pfSense would be ideal) that allows Netflix, Hulu, etc to work with a Roku or Smart TV while blocking things like facebook?

I understand that Netflix is going to track me when I'm a Netflix subscriber, but why should Facebook do it?

<comment><USER70> On an Android smart TV, I run a DNS changer and point it to local pi-hole to block trackers and ads aggressively. Not sure if it ends up cleaning up everything but I do see 15% of the DNS queries pi-holed.

</comment></comment><comment><USER71> [https://www.washingtonpost.com/technology/2019/09/18/you- wat...](https://www.washingtonpost.com/technology/2019/09/18/you-watch-tv- your-tv-watches-back/)

</comment><comment><USER72> I blocked these URLs on my router, and my Samsung TV went into a setup mode, eventually switching languages into German.

config.samsungads.com samsungacr.com samsungads.com samsungcloudsolution.com samsungcloudsolution.net samsungotn.net samsungtvads.com

</comment><comment><USER73> Is there a manufacturer that is better in this regard? I assume Samsung would be the worst.

</comment><comment><USER74> I wonder - how prevalent is this in vehicles now? My car probably knows where I am, what podcasts I listen to, my daily routine, all sorts of things. It can connect via 3g without me knowing it and send all sorts of usage data.

This is why regulation is IMPORTANT. A whole industry can decide this is their business model, an industry where competitors can't really get in, and consumers are screwed. Well just don't drive a car, just don't use a tv is not a valid argument.

</comment><comment><USER75> My LG TV webOS YouTube app, generates some hard to hear sounds when menus and content is navigated. Even thought I am not logged in in YouTube app, I suspect they can be captured by an Android device nearby and correlated with that device user. The apps that have the login data already can share whatever they like. There was a story some years ago when even shared local media names were shared by some TVs. If you have a device connected to network, you can be sure it will share whatever it can, malice intent or not.

</comment><comment><USER76> For years, we've been avoiding this whole problem. We have a dumb TV hooked up to a computer. The computer doesn't even have a fancy couch-friendly interface installed. It's just a computer. And therefore, it literally plays all media we want, and if we prefer, it blocks ads and plays music too. The computer doesn't spy on us because we control it, and websites only spy on us to the degree that we're unable to prevent. (pihole, ublock, etc)

</comment><comment><USER77> The next time that Apple comes out with a new model of their Apple TV 4K (likely next month), I plan on buying one and completely disconnecting my smart TV from the internet.

My TV's UI is incredibly laggy and Vizio forces upon me a barely tolerable UI with the first two rows on the main page consisting of unhideable suggestions on what I should watch---even content that I cannot watch since I'm not subscribed to every service.

</comment><comment><USER78> My TV is completely airgapped now for privacy reasons, but I really wish there was a way to replace the OS running on it.

I used to be(and still am) a big fan of the Smart TV concept, seeing as there's a whole quad core ARM SoC built into my TV that might as well take the streaming duty instead of having an extra HTPC or Chromecast lying outside of it.

</comment><comment><USER79> I am starting to think I should block all traffic out of my home network and force everything to go through a proxy server where I can manage all outbound traffic.

The number of devices I have plugged into my home network is astonishing and the chatter / discovery they do to each other is interesting to watch.

Zero trust model for everything ... I guess ?

</comment><comment><USER80> It's been this way for a while. That is why I get 4K Monitors, not a "smart TV". If a monitor has anything beyond a hdmi jack, I skip it.

Cars are going this way too. The current model year has all car manufacturers producing these ruined vehicles. Hold what you got, or buy used until this bullshit is regulated away.

</comment><comment><USER81> Stallman has been telling for a while that "smart" devices mean devices that spy on you.

</comment><comment><USER82> I went in to my router to block my Samsung TV last night and thought it was cute that instead of using the device name I set it was using "localhost". I guess these companies will go to any extreme to steal your info.

</comment><comment><USER83> Android phones talk to Facebook too even if you don't have an account or any of their apps.

<comment><USER84> Source?

<comment><USER85> If you run an app that uses Facebook libraries. This is true on iOS, the web, and any other platform as well.

<comment><USER86> This feels less like an Android issue than it is a Facebook issue (which I say without implicitly defending Google's privacy-breach record).

</comment></comment></comment></comment><comment><USER87> Do they send data from games consoles? I watch TV entirely through my PS4, with the actual smart TV not hooked up to my wifi. I presume that would stop TV companies from getting my data, but then again Sony might sell it themselves.

</comment><comment><USER88> There is a simple way around this- never connect these to your LAN. I don't need the features, I don't need the data collection, and I certainly do not need the extra security footprint.

</comment><comment><USER89> I use Kodi on a Rasbperry pi. There is a plugin for Netflix (which I dont use due to the content restrictions they have in Australia thanks to the Foxtel monopoly). Problem solved.

</comment><comment><USER90> I've made a point to not enable or connect my smart TV to any network. I'd rather use services over other devices anyway.

Granted there are plenty of other ways to get that data.

</comment><comment><USER91> Worked in this industry for years. It didn't really feel right at the time. Adverts on volume buttons. Frames of video sent to third parties. Etc

</comment><comment><USER92> But why would anybody NOT want a smart TV? /s

</comment><comment><USER93> Spy TVs are nothing compared to Spy energy meters.

They will bring in a new era of surge-based pricing, which will eliminate all tariff comparisons as it will be impossible to compare.

Higher pricing is already starting with non-spy tariffs being more expensive than spy tariffs.

If you happen to buy a home with one, and want the spy meter removed, you are at the mercy of the supplier and they will embark on a campaign against you to keep it. The lies will soon start saying they have no analogue meters in stock etc.

</comment><comment><USER94> I think is must be possible to shutdown the smart TV OS and watch your TV box with Libreelec via HDMI instead.

</comment><comment><USER95> What if the communication is benign? What if the TV is simply refreshing a list of recommendations? Everybody - including this forum - is so primed to read nefarious motives into basically anything a computer can do now. Soon we're not going to be able to write a single "hello world" app w/o having to fill out a ream of EU paperwork and get licensed and bonded in advance.

<comment><USER30> "Recommendations" is just newspeak for advertising. I don't want my TV doing that.

Here is a novel idea: if your shit is so great for users, not contrary to their interests, why don't you ask them to opt-in?

</comment></comment><comment><USER96> Not just to Netflix and Facebook. This is why I don't, and won't ever, own a smart TV.

</comment><comment><USER97> I have assumed any device around me is sending my data somewhere not intended. Period.

</comment><comment><USER98> Odd. Most of the discussion here is about the TV and the collection, few seem interested in where that data is being sent? Has the shameless nature of Netflix's and FB's privacy invasions been normalized? Ironic given that Snowden's book dropped this week.

</comment><comment><USER99> Smart TV's are only for stupid people. If you have one, unplug it from the internet, this removes the smartness. Add back your own smartness with a "NUC" kind of computer. Now you have a dumb TV and a smart owner.

</comment><comment><USER100> when I wanted a 4K, I made sure it wasn't a smartTv for the reasons outlined in the article and comments. hard to find, but walmart had their own dumb 4k tv

</comment><comment><USER101> Guess what. Apple tv NOT on the list..spend the 150$

<comment><USER102> But the Apple TV doesn't have a screen and it's hard to find a decent "Dumb" TV to even hook up a Roku/Apple TV/Chromecast to these days.

</comment></comment><comment><USER103> Get yourself a Pi-hole. Block all phone home attempts. [https://pi- hole.net/](https://pi-hole.net/)

<comment><USER104> It can't possibly block all phone home attempts. How would the Netflix or YouTube apps work on those devices if network traffic to those respective third-parties were blocked?

</comment></comment><comment><USER105> Gee who would have seen that coming...

<comment><USER105> Might as well buy an Alexa, LOL...

At this point, people have to wonder what benefits the IOT fabric provides THEM versus what benefits it provides the vendor or configurator/bundler...

Of far greater concern is the pile of unpatched linuces these crapware bloatware "embedded linux" devices tend to be equipped with. It's an entry vector...

or hardcoded "admin:admin" login credentials...

</comment></comment><comment><USER45> Any AOSP android tv boxes out there?

</comment><comment><USER106> and we don't answer out names to unknown phone calls made by our friends :P

</comment><comment><USER107> Just assume almost everything is a data grab and you will be right more often than wrong.

</comment><comment><USER108> no surprise here, but is my pi-hole blocking this crap?

</comment><comment><USER109> Kodi > SmartTV

</comment><comment><USER110> [https://archive.is/jOJ3R](https://archive.is/jOJ3R) link to archived version of article. FT usually hides things behind a metered paywall.

</comment><comment><USER111> time to get a dreambox with a keylist

</comment><comment><USER112> Great!

</comment><comment><USER113> Do these TVs have different default settings for the EU market (GDPR)? If not, this seems like a great way to get slapped with handsome fines for GDRP noncompliance...

</comment><comment><USER40> Can we breakup Facebook and put their executives on trial already?</comment>


Frequency Modulation (FM) with Web Audio API - <AUTHOR> http://greweb.me/2013/08/FM-audio-api/

<comment><USER2> It's a nice article, but I think there are some important things to note here:

Typically, what we call "FM synthesis" is implemented as phase modulation -- instead of modulating the frequency of the carrier, you modulate a phase offset. That way, the amplitude of the modulator won't have to be scaled with the frequency of the carrier for a uniform timbre over the whole frequency.

My second note is that most FM synthesizers (the whole Yamaha range, basically) don't define the frequency ratio increments in octaves or quarter octaves, but simply as multiples of the base frequency, producing a harmonic series. Most implementations do this in integer increments, but others like the DX7 and TX81z let you use fractional frequency multiples.

<comment><AUTHOR> I have no music background, so thanks a lot, your feedback is really helpful :)

When you say modulating a phase offset instead of frequency, does this mean you have like 2 oscillators A and B set to the same frequency, where you modulate the offset of A, and you connect both A and B to the audio output?

About your second note, you are so right! Actually it was a mistake in my article, this is what I've done actually but my explanation was a bit wrong. My first demo is a multiple of the frequency. My second demo is a multiple of (carrier frequency/4). Nothing related to octave, I shouldn't have mentioned that (I will fix it ASAP).

<comment><USER2> Hey, no problem. FM synthesis is one of my greater interests! With modulating the phase offset I mean that instead of doing

        carrier = sin((f + modulator) * pi)

(a typical way of modulating the frequency) you can do

        carrier = sin(f * pi + modulator)

The modulator could be scaled by something from 0 to 2 pi but experiment with what sounds best.

The reason for doing this to begin with is probably that simply adding an offset in a sin table readout is probably a more effective design than adding the offset to the phase accumulator, especially if you want a consistent timbre without scaling the modulator amplitude along with the carrier frequency, and don't want to deal with negative frequencies.

Another nice thing you get for free with phase modulation is that you can do stable feedback modulation. In essence, you use the last calculated sample value for an operator (envelope * oscillator) as a modulation source in itself. In code, something like

        float generate_sample() {
            sample = envelope * sin(f * pi + old_sample * feedback_level);
            old_sample = sample;
        }

It's very effective for brass sounds or harsher sounds like trying to model distorted guitars

</comment></comment></comment><comment><USER3> For what it is worth, I have made a similar work with much less details and very poorly designed, but here are some cool FM instruments: [https://github.com/tfjgeorge/jsfm#gong](https://github.com/tfjgeorge/jsfm#gong)

To hear the sound click the speaker on the right (works at least with Chrome).

<comment><AUTHOR> Woo, that's cool man! All these demos around Web Audio API.. Future is awesome!</comment></comment>


Slackware Turns 20 - <AUTHOR> http://ostatic.com/blog/slackware-turns-20

<comment><USER2> Slackware was the first Linux distro I used, back in 1999. Eventually left it for Debian. Glad to see it's still around and that Patrick is seemingly doing better health-wise.</comment>


World premiere of the Volocopter series model 2X - <AUTHOR> http://press.volocopter.com/index.php/press-releases-main/english-kategorie/109-world-premiere-of-the-volocopter-series-model-2x-the-flying-taxi-is-just-about-to-be-launched-onto-the-market <comment><USER2> Let's see whether the eHang really goes life in Dubai this year.

The Volocopter has had unmanned and manned test flights since last year, and is on track to be certified by German authorities next year - looks quite promising.

Achilles heel, of course, is battery life, but this 2x model seems to have a quick-swap battery - that makes a lot of sense.

</comment><comment><USER3> This type of transportation can't come soon enough! Glad there is more coming out from volocopter Want the ehang introduced just under 2 years ago? And looked to be vaporware, but then they've made the claim they'll be flying this summer. Would love that to happen.

</comment><comment><USER4> Aeroplanes Glide, and Helicopters Autorotate, what does the eHang or the Volocopter do if it loses power?

<comment><USER2> Volocopter has 3 * 6 = 18 rotors in 2 concentric circles, and several different power trains, which run rotors opposite each other. So, up to 4 rotors can fail, and you can still achieve a controlled landing.

If more fails, there's a ballistic rescue chute (which requires a certain altitude).

My gut feeling is that it's better than a piston engine, and comparison to a modern turboprop/turbojet/turbofan remains to be seen. But clearly an electric engine has fewer moving parts.

Edit: Don't know so much about the eHang safety concept, but the whole thing looks dodgy to me, to be frank. The 4 twin rotors don't seem to offer much redundancy, and are conveniently located to chop knee caps... Dunno.

Also, disclaimer: I've invested 1000 EUR into the Volocopter. Thus, I'm clearly biased :-)</comment></comment>