Implausible and overfunded CPAP machine on Indiegogo - <AUTHOR> My son (a physics student) wrote to me to point me to a crowdsource project for a CPAP machine.
https://www.indiegogo.com/projects/airing-the-first-hoseless-maskless-micro-cpap#/story
My immediate thought upon seeing the mock up was: balony, with a capital 'B'.
It is a tiny thing looking a little like a plastic moustache.  I do not see how such a small package could store enough power to run a CPAP device.  It is a simple question of moving mass.  People breath about 5 liters of air per minute at a low activity level. That's 2400 liters in an-8 hour period.  Air weighs about 1.2 gm/l = 2.88 KG moved in an an 8 hour period.  And that illustration did not seem to have much space for a battery.  Not to mention space for the magical flapping air pumps derived from CPU coolers!
And they claim a price of $3 per device…  And it's disposable.
They also say they are using a zinc air battery, which has energy density of 470 Wh/kg or .47 Wh/gm. Let's generously say that they have 10 gm of battery—that's 5 watt hours.  Lets even more generously say that they have 8 watt hours.  That's 1 watt continuously for a night of sleep.
They are saying they can operate a CPAP machine on 1 watt, have it be the sized of a junor tootsie bar, and sell it for $3 per device.
The question I'm asking here is what should we do as engineers?  Ethically, I mean.  I really hate to see people taken in by such an obvious scam. <comment><USER2> Let's try the math for real.

The site claims that the device can provide 20 cm H₂O (which is ~1961 Pa). Apparently some hypothetical normal man breathes at a rate of 6 liters (i.e. 0.006 cubic meters) per minute at rest [1]. If you pump a volume V of fluid across a pressure difference of ΔP, you've done work V·ΔP, which is 11.76 Joules per minute or 0.1961 Watts. Keep in mind that this is the work done, not the power consumed, but let's be generous and assume a 100% efficient blower. We'll also assume that no power is harvested during exhalation.

In eight hours, that's 1.56 Watt hours.

Duracell's zinc-air chemistry claims up to 442 Watt hours / kg [2]. That's about 3.5 grams of zinc-air goo per night, ignoring packaging, blower loss, etc.

This seems entirely plausible to me.

[1] [http://www.normalbreathing.com](http://www.normalbreathing.com)

[2] [http://media.ww2.duracell.com/media/en- US/pdf/gtcl/Technical...](http://media.ww2.duracell.com/media/en- US/pdf/gtcl/Technical_Bulletins/Zinc%20Air%20Tech%20Bulletin.pdf)

Edit: In the interest of precision, I should add that the analysis is accurate for an incompressible flow. Air is definitely compressible, so, if you pump air, more volume is going into the pump than is coming out, and you're heating up the air (adiabatically if your pump is any good). So, with a compressible fluid, you have to consider not on the work done moving the fluid across a pressure difference but also the energy you've stored in the fluid by pressurizing it. The pressure difference for CAP is tiny here, though, so this would be a miniscule correction to the math above.

<comment><USER3> Well now I guess I have to do the math:

W = P(b)V(b) ln(P(a)/P(b))

([https://en.wikipedia.org/wiki/Compressed_air_energy_storage](https://en.wikipedia.org/wiki/Compressed_air_energy_storage))

CPAP requires roughly 10 cm of water pressure = 0.01 Bar Sea level atmospheric pressure is roughly 1 bar So the device has to pressurize to 1.01 Bar Now I've looked it up, and a typical CPAP machine moves 20 to 60 liters per minute Let's say 30 liters per minute = 1800 liters per hour

W = (1.007) _(1.8)_ ln(1/1.007) = (1.81)*(-00698) = 0.0127 MJ = 3.53 Watt Hour

So assuming perfect efficiency you would still need 28.64 watt hours of battery, just to do the compression.

470 Wh/kg for Zinc-air battery implies this device requires a 60gm battery (2 oz to those of us of a certain age)

I looked up CPU fan efficiency (what they say they derived it from) and PEAK fan efficiency only approaches 25%

[http://www.nmbtc.com/fans/white- papers/fan_efficiency_import...](http://www.nmbtc.com/fans/white- papers/fan_efficiency_important_selection_criteria/)

So, you'd really need an 8 oz battery hanging from your nose to make this work, not counting what you need to run the electronics, etc.

<comment><USER2> Where does that 30 liters per minute go? I'm reasonably sure it's not going into the user's nose or mouth.

Part of the claimed innovation here is that the thing sticks directly into the user's nose. If it seals well, it's plausible that there's very little wasted air, which would account for the factor of roughly five.

(Also, you used the formula for isothermal compression, I think. A tiny little device like they showed would probably move air quickly enough through its fan that it would be closer to adiabatic. This doesn't matter much for the small pressure change involved.)

<comment><USER4> > Part of the claimed innovation here is that the thing sticks directly into > the user's nose.

Putting the whole machine in the nose is novel, but I don't see how that is innovative in terms of changing required functionality compared to nose-only masks, which are already a thing.

<comment><USER2> It shouldn't have anything to do with the required technology. It might allow a considerable reduction in leakage, though.

</comment></comment></comment></comment></comment><comment><USER5> I work in the sleep industry, and noted that the company making this device did not attend Sleep 2015 in Seattle. The fact that they were not present at the largest gathering of sleep professionals in the country this year made me really doubt their credibility.

<comment><USER6> Noting whether a company has been to their industries largest gathering of professionals doesn't seem like a particularly robust metric upon which to judge future success.

</comment></comment><comment><USER7> "People breath about 5 liters of air per minute at a low activity level. That's 2400 liters in an-8 hour period. Air weighs about 1.2 gm/l = 2.88 KG moved in an an 8 hour period."

I'm not sure if this device is plausible, but I know this calculation is not useful. You're calculating the mass of air moved, which, first of all, does not itself say much about the energy required to do so; for instance, horizontal motion doesn't require any net energy (though any real device doing so will of course need to do something to accelerate and decelerate, there's nothing to say it can't be very, very cheap). Second you appear to be discussing it as if there isn't a pair of lungs right there providing motive power. I do that much moving of the air every day (plus a bit, probably, I'm a tall guy) with no batteries at all.

This thing is not responsible for "moving all that air"... it's responsible for a _pressure increase_ of the air, which is at least somewhat equivalent to saying it's responsible for "moving air" but only a fraction of the value you computed. They say it is supposed to do from 1 to 20 "centimeters of water". According to the Great and Mighty Internet, 20 cmH20 is 0.02 atmospheres, just to give some perspective. I do not have the math to calculate the energy requirement that represents when the air is in motion itself; my physics would only be sufficient to calculate the energy implied in pressurizing a closed container from 1 to 1.02 atmospheres, which is useless in this case. Perhaps someone else can pop up for that.

(Bear in mind I took a full standard College physics-for-non-majors course set, using full calculus, and what I know from that is that what I know is inadequate... if that also describes your experience, your education is inadequate too. We're going to need to hear from someone with more specialized education.)

My suspicion is that yes, this device _is_ plausible, but the final version is going to be larger than the versions shown. Whether it crosses over the invisible line where people become unwilling to wear it is anybody's guess, but... sleep apnea _sucks_ and those masks do suck too, so there's some room for these guys to work in. I'd classify this as a "considered risk" rather than "two orders of magnitude impossible". I reserve the right to change this assessment as more data comes in, especially a (good!) physics analysis of the real energy required to do this.

<comment><USER8> 20 centimeters of air is a LOT more than it sounds like. I personally run a pressure of 14 cmH20 and the airflow needed to maintain this is a LOT higher than that needed for breathing. I run a full face mask and my machine averages flow of around 30 liters a minute. The air needs to be "turned over" constantly since you don't want to be re-breathing stale air.

(As a side note to GP: Reducing/stopping pressure on the exhale is problematic also... for some of us many of our problems are actually on the exhale.

<comment><USER2> I know basically nothing about how CPAP devices work, but why does it need to move so much air? There are snorkels on the market with little check valves so your exhaled air goes out a different pipe than your inhaled air. They cost maybe $20. I can't imagine that a super-expensive CPAP machine doesn't have a similar pair of valves.

<comment><USER8> Basically, because you're sleeping, and even a good mask seal will leak a fair bit, and there is also a lot of intentional leakage around the valves because you don't want stale air hanging around, or condensation building up, and you have to make sure that the person can breathe sort-of normally if the power fails or something like that.

<comment><USER2> As a guess: with a plugged-in device, the manufacturer doesn't care about power consumption, and the thing already needs to be be able to supply enough air for the peak flow while you're inhaling, so it doesn't really matter if it leaks.

If they cared about power consumption, they could presumably make it less leaky and use check valves to prevent issues with stale air or inability to breathe if the fan stops working.

I've used snorkels with separate in and out tubes and check valves to route the air correctly. It solves stale air problems (which are irrelevant for snorkling because the total air volume is much less than the amount of air you breathe in per breath) and causes serious suckage (because you really want your exhaled air to displace water that comes in the intake, and check valves prevent that), but for CPAP it might make sense.

</comment></comment></comment></comment></comment><comment><USER9> When you look at the math (as you have) it seems almost certain to be a scam. ResMed has a Technical note [0] on powering one of their devices form a battery, while product efficiencies can vary they are recommending ~30 Amp hour batteries for the 20 cmH20 this device is claiming to provide. It amazes me that indigogo doesn't do something to stop this sort of thing when it gets to be such a well funded project (I'm sure other platforms are guilty of it too).

[0] [http://www.rpc.com.au/pdf/battery-powering-products- usa.pdf](http://www.rpc.com.au/pdf/battery-powering-products-usa.pdf)

</comment><comment><USER10> _Is the Airing device FDA approved? No, not yet. However, we do believe the process of getting FDA clearance may be abbreviated._

Ha. I work at a company that makes medical devices. It's just so damn easy, you know! Seems like a pretty blunt case of handwaving away this critical step. This is an electric device that controls if you can breath. This thing has a non-trivial risk of hurting someone through electrocution (it's plugged into your conductive mucus) or asphyxiation (though hopefully you'll wake).

So yeah, they'll clearly just POST to the FDA certification API and get a response within a minute.

</comment><comment><USER11> Everything seems to be worded just right in case they don't deliver. From the FAQ: "As a contributor to this Indiegogo crowdfunding campaign, you are supporting Airing's intent to develop the world's first micro-CPAP device."

Also, all physical perks have the disclaimer: "Subject to FDA clearance and doctor's prescription in the US and local regulation abroad."

From a financial perspective, I can't imagine getting the device certified in multiple countries is going to be cheap. Would they also be expected to check doctors prescriptions in various languages somehow before delivering?

</comment><comment><USER12>
       > what should we do as engineers?

Well you can warn people off, but you can't make people disbelieve what they want to believe. In similar situations I've suggested that folks wait until they can be ordered and the crowd funded units have shipped. Then they will have a good idea of what they are getting. If the crowd funding fails or they are poor quality, they will have saved themselves aggravation and money, if it works then they will be available as a product.

</comment><comment><USER13> If anything, this underscores the importance of this field. Sleep is an under- studied phenomenon. Sleep apnea is even more so... Consider the current field of options, none of which may be any better than the one proposed on Indiegogo. All you need to do is flip on some infomercials or flip through a SkyMall magazine to see that there are dozen of gizmos and gadgets that don't work: chin straps, sprays, OTC mandibular advancement, etc.. etc.. The surgical options are not pleasant either. Look up "UPPP".

One promising technology is a small pace-maker-like device that is implanted in the chest and stimulates the hypoglossal nerve while you sleep: [http://www.medscape.com/viewarticle/834474](http://www.medscape.com/viewarticle/834474)

<comment><USER14> I believe my neurologist was one of those who helped develop that device (Cornelius). Can't log in to see, but sounds like the same thing. But, he keeps me on an adjustable CPAP machine instead because of how my sleep apnea works.

</comment></comment><comment><USER15> It looks like the found a good gullible market with lots of money, and it will be _years_ before anyone complains. They have an earliest delivery date of 2017 depending on how things go with the FDA.

When I see something like that my first question is if the doctors involved are real or not.

<comment><USER3> The doctors looked suspiciously like models. I tried google image searching them but I think the oval surrounds threw it off. I'd bet they are fake as well.

<comment><USER16> There isn't a Doctor Jeffrey Bass working at Brigham and Women's Hospital [0]. There isn't an obvious email address either, so I can't just ask them if he previously worked there or if the picture matches.

[0] [http://physiciandirectory.brighamandwomens.org/?Index=10&Las...](http://physiciandirectory.brighamandwomens.org/?Index=10&LastName=bass)

<comment><USER17> If you Google Jeff Bass and Brigham, enough hits come up to make you think that he had some sort of association with that hospital [0]. This picture here (far left) [1] looks like the same person.

[http://health.usnews.com/doctors/jeffrey- bass-342891](http://health.usnews.com/doctors/jeffrey-bass-342891) [0]

[http://www.personalmds.com/doctors/bios](http://www.personalmds.com/doctors/bios) [1]

<comment><USER16> Interesting. Your google-foo is obviously better than mine. I googled the name but the only photo I got was the one from the CPAP page :)

</comment></comment></comment></comment></comment><comment><USER18> _I 'm no engineer and my knowledge of CPAP extends to the amount of Googling I did since I saw this post._

Their constraints do seem very tight but I can conceive at least one way in that you could shrink the device down. There would be multiple actions in such a device:

1\. During the inhale increase pressure. As noted by the image[1] this is achieved in the device with "blowers."

2\. During the exhale present a restriction to airflow, but don't cut it off entirely. You could use something similar to an aperture to restrict airflow here.

3\. Between the exhale and inhale maintain pressure. If you use an aperture- like-device you can simply close the aperture completely.

This means that the device becomes _partially_ passive, reducing power requirements. I'm no expert but let's assume that you are only inhaling 50% of the time - this cuts down the amount of time the "blowers" need to run by 50% (or can double their power consumption or something in-between). My uneducated opinion is therefore: remotely plausible.

[http://res.cloudinary.com/indiegogo-media-prod- cld/image/upl...](http://res.cloudinary.com/indiegogo-media-prod- cld/image/upload/c_limit,w_620/v1434341774/oszvr8ppyhnqsmj56jip.png)

<comment><USER3> I don't follow your logic at all.

And you do not escape the fact that the device has got to move almost 3 kg of mass with about 1 watt.

<comment><USER18> > I don't follow your logic at all.

I have another try at communicating the idea.

It _sounds_ like the main problem with sleep apnea is that the air passages are collapsed when it comes time to start inhaling - preventing the process from occurring. Therefore the core of the solution is having "inflated" air passages at the point when inhalation starts.

The idea is to kick-start the next inhalation with the current exhalation. When you exhale you increase the pressure in your air passages which is work ("wattage") that completely goes to waste - it all goes out your nose/mouth. The device would gradually restrict the passage of air out of the nose (as the exhalation process completes), eventually cutting it off completely. This means that once you have completely exhaled your air passages would still be "inflated." This is what (2) and (3) do. In this situation conventional CPAP would be providing pressure (even though it's not needed) and would hence be wasting work.

That is the special sauce: relying on the human to do work that they _don 't_ have problems with. This will reduce the amount of work you need to do to assist with their medical condition: possibly down to 1 watt, or at least way less than you'd need with conventional CPAP.

> 1 watt

The problem is collapsed airways and not dysfunctional lungs, there's still plenty of wattage there: all you need to do is keep the air passages open using (1).

As I said: a long-shot, remotely plausible. Most importantly: if the above is a plausible idea there is no guarantee that it's the same as theirs or that they even have one. Show me the patents.

At the same time it's better to ask questions before initiating a witch-hunt. I think the first plan of action would be for them to prove that they have a working device instead of the seemingly common "warning off people" suggestion. A better suggestion to people is encourage them to ask for proof.

</comment></comment></comment><comment><USER19> Background on Airing, LLC, located in Burlington, MA.

I looked up Stephen A. Marsh (see [http://www.fundairing.com/](http://www.fundairing.com/) under 'inventor').

Interesting guy - a strange history. He also is CEO of Encite LLC (also located in Burlington, MA). He does have many patents in fuel cells, etc.

Previous to Encite LLC he was CEO of a now-defunct technology startup Integrated Fuel Cell Technologies, Inc. (IFCTI)

Encite LLC was formed from IFCTI, through some obtuse legal machinations.

[http://www.potteranderson.com/delawarecase-185.html](http://www.potteranderson.com/delawarecase-185.html)

I am no expert in law, but it sounds like he basically ran IFCTI into the ground as CEO, then bought it and its resources back at a large discount via Encite LLC. The previous board members tried to sue him but lost due to some ambiguities in the laws.

Maybe someone else has more?

BTW having used a CPAP I know it is not possible to generate the volume and pressure (particularly the pressure) needed by something this size without a quantum leap in current technology.

I can't devise a method to prove and explain my conclusion. Perhaps someone more versed in the area can.

</comment><comment><USER20> _The question I'm asking here is what should we do as engineers?_

Talk about it and spread the word to others that this is impossible to do.

There's also some interesting discussion here, mostly to the tune of "it won't work":

[http://www.eevblog.com/forum/crowd-funded-projects/the- airin...](http://www.eevblog.com/forum/crowd-funded-projects/the-airing/)

<comment><USER3> Thank you for pointing that out. It was interesting reading.

I was hoping that someone in this community would know someone in indegogo responsible enough to say wait a minute, this is not plausible. I took a look at indegogo's terms of service and found only this:

"If the Campaign is claiming to do the impossible or it's just plain phony, don't post it. "

Which is pretty weak.

But I suppose the old saw that 'a fool and his money are soon parted' still applies in the crowdfunding world...

And here's a -real- battery powered CPAP machine, taking a laptop-type lithium ion battery:

[http://www.cpap.com/productpage/Hoffman-Laboratories- Breathe...](http://www.cpap.com/productpage/Hoffman-Laboratories-BreatheX- CPAP-Viasys.html#specs-tab)

</comment></comment><comment><USER21> You are forgetting that it is your _lungs_ that must move the 2.88KG in an 8 hour period.

The machine just has to maintain a positive pressure during certain portions of the breathing cycle.

What I see here is a possibly overly-ambitious design, but no obvious scam.

BTW, here is a video of Airing's Chairman: [https://vimeo.com/130685879](https://vimeo.com/130685879)

<comment><USER8> This is a much harder problem than you give it credit for. The pressure has to be maintained over widely and rapidly changing conditions. For instance, if the patient suddenly takes a deep, fast breath, the pressure needs to be maintained.

</comment></comment><comment><USER22> I don't think there is an ethical obligation to do anything. I hope people contributing can afford to lose whatever funds they are pledging. They will have to seek FDA approval. If they don't get it, no one is going to be buying some overhyped piece of plastic that doesn't actually work.

One of the challenges we have currently is that the medical field is over regulated and there are excessive barriers to entry. Perhaps you can make your peace with the fact that it isn't your money and if people want to hope against hope for something better and pledge a few dollars, that is their choice. Then the developers might get their shot at developing something new. Maybe it won't meet every criteria they listed. Maybe it somehow will. Maybe it will be a complete flop. (Shrug)

Innovation only happens when there is some leeway for some of it to fail. $100k is a drop in the bucket for medical research. Why do you feel such a strong need to not even let them try? I suggest you let it go.

</comment><comment><USER23> > The question I'm asking here is what should we do as engineers? Ethically, I > mean. I really hate to see people taken in by such an obvious scam.

Skepticism is certainly warranted based solely on the timeline presented and my experience in medical devices.

As to the rest, you're operating on incomplete information. According to the NSPE, "Engineers may express publicly technical opinions that are founded upon knowledge of the facts and competence in the subject matter." You say, "what should _we_ do as engineers", so I'll make the implicit assumption that you're an unlicensed "software engineer" like many on HN. If so, consider that you may be operating outside your area of expertise without complete knowledge of the device. I would make careful public statements: I, for example, wouldn't say "I performed a first-principles analysis and, as an engineer, I find the device claims are impossible."

<comment><USER3> Well I never took the PE exam, and it is a couple of decades since my undergrad and graduate engineering degrees that included a couple of courses in thermo, so things are a little rusty, but prodded by a few of these posts I've just dusted off the math and made a go of it. BEST case, requires an 8 oz zinc-air battery. And they are going to sell that, and the device itself for $3..?!

Part of my reaction is that I am a patent attorney, and every patent attorney gets 'inventions' that come through the door from well-meaning but essentially clueless people. After a while you get to develop a bullsh*t detector. This one just rang my gong. I suffer from sleep apnea and I know what a real thing it is, and the idea of these guys just walking away with $$ from desperate people, just, again, rang my gong.

I will say that it has been fun seeing these posts--thank you!

</comment></comment><comment><USER24> There is breathing going on here so is there any chance that the breathing out could help recharge the battery in a similar way that a hybrid car charges your battery when you brake?

I also don't think it is 'disposable'. I think it is recyclable and from what I've seen the $3 is dependent on recycling them.

<comment><USER8> No. To be effective CPAP has to be continous, even during the exhale.

<comment><USER14> Most of the machines sold now are continuous, but not at constant pressure. Mine's set to detect apnea events and adjust between 5-15 for pressure and to adjust that further based on exhalation.

<comment><USER8> Yea, for sure.

Mine can do all that, but I actually have it all turned off...I find I have a much easier time getting and staying comfortable that way...every time the pressure changes my mask would shift...at a constant pressure I can get it "just right" and it doesn't leak at all and I find it easier to fall asleep as the pressure points don't shift around.

</comment></comment></comment></comment><comment><USER25> I believe the Airing thing is expected to use these things:

[http://www.murata-ps.com/emena/2012-05-22.html](http://www.murata- ps.com/emena/2012-05-22.html)

I was also skeptical of the Airing claim, although after reading about the Murata piezo blower things, they're amazing, whether Airing is able to make a CPAP out of them or not.

Frankly, as an old, fat, CPAP using guy, I'd rather eat mouldy cheese than use a nasal pillow CPAP device. Plus, the Airing thing would have to be strapped to my face anyway; at my Rx pressure it'd blow out of my nose within an hour. The hose on my traditional BiPap turbine machine doesn't bother me at all.

I'd be delighted to have a smaller BiPap machine made out of these Murata things, if it meant a less bulky power supply and a smaller base unit.

<comment><USER19> That was a really impressive find!

Armed with this, I took interest in your response and checked out the math.

Interestingly, this device seems to produce the pressure!

Using their specifications of the piezoelectric pump on the page you sent.

Piezoelectric pump produces 1.5kPa. This converts to 15.3 cm WC (centimeters of water column) or cmH2O. 4-20 cmH2O is the range of a cpap!!

But, the airflow needed at that pressure is a critical issue as long as you want to breathe freely. The piezoelectric pump produces 0.8 liters per minute.

At [http://www.sleepdex.org/cpap.htm](http://www.sleepdex.org/cpap.htm) it says a cpap produces 20 to 60 liters of air per minute (lpm).

To reach the lowest end you need 20 lpm. Calculate 20 / .8 = 25

So you need 25 of these piezoelectric pumps to reach the lowest possible; 75 of them to reach the high end. This is literally almost an order of magnitude.

And in case you thought so; piezoelectrics can't scale. They are very limited in size, by the physics of the vibrations.

So still not even close. It would require a quantum leap in technology over what we have available.

</comment></comment><comment><USER26> Buy the right to post comments by pledging the smallest amount possible? Contact indigogo with the concern? Write a blog post and get help having it widely linked? Alert the authorities?

On the other hand, it might br hard to convince a lot of people that this isn't real. After all, most of humanity believes some version of supernatural nonsense which includes such things as people flying, resurrecting, partin seas, singing bushes, talking snakes, 6,000 year old earth, rapture, being chosen, paradise, etc. in other words, there's plenty of empirical evidence to show science and reason don't stand a chance. Yet.

</comment><comment><USER27> Call Indiegogo to task. They're developing a reputation for shady practices. Considering they get their cut whether the startup is real or not begs the question are they honestly diligent in vetting a project? Given their history it seems to me they're more interested in their piece of the pie and believe those foolish enough to buy in get what they deserve. You won't see them refunding their portion of a fund when it becomes apparent it was a scam. They carefully pretend nothing bad happened and go on down the road to the bank.

</comment><comment><USER28> I'm fairly skeptical myself, but if they do put their money where their mouth is, this will be a fantastic product. I use a cpap, and I can tell you flying international lugging a machine around is a regular pain in the ass.

That said, my dollars are staying snugly in my pocket for this campaign. It's pretty farfetched, and I don't like the metric they used to illustrate the actual pushing power. It doesn't add up.

</comment><comment><USER29> Maybe the doctors are being scammed as well? Gilmartin specializes in sleep medicine

[http://www.vitals.com/doctors/Dr_Geoffrey_Gilmartin/profile](http://www.vitals.com/doctors/Dr_Geoffrey_Gilmartin/profile)

<comment><USER30> I can't speak to Dr. Gilmartin himself, but being a doctor doesn't make you an engineer capable of evaluating a complex medical device. My pulmonogolist is a good doctor and understands how to best configure my own CPAP for my health. He really has little idea how the thing actually works.

<comment><USER31> Gilmartin doesn't need to know the engineering principles involved, just that it provides the claimed the medicinal benefits. As a doctor that's _exactly_ what he's qualified to assess. Besides, he's a doctor _at Havard_ , there'll be some very qualified engineers around to assess that side of things.

</comment></comment></comment><comment><USER32> You really don't need to read the page further after seeing 'flexible funding' with a target of 100k. Sadly indiegogo is a scamsta's paradise for allowing flexible funding for non-charity drives.

</comment><comment><USER33> The fact that their anticipated price is $3/day is absurd. I can't see insurance companies rushing to cover this.

<comment><USER34> "The costs of untreated sleep apnea reach further than just health issues. It is estimated that in the U.S. the average untreated sleep apnea patient's annual health care costs $1,336 more than an individual without sleep apnea. This may cause $3.4 billion/year in additional medical costs. Whether medical cost savings occur with treatment of sleep apnea remains to be determined."[1]

So if it turns out that this treatment of sleep apnea can offset those increased healthcare costs, I could definitely see insurance companies being interested.

[1] Kapur V, Blough DK, Sandblom RE, Hert R, de Maine JB, Sullivan SD, Psaty BM (September 1999). "The medical cost of undiagnosed sleep apnea". Sleep 22 (6): 749–55. PMID 10505820

<comment><USER14> CPAP treatment (and no other substantial changes in my life) brought my blood pressure down from 160/110 down to 118/78\. Previous doctors had tried, without success, to lower it with massive beta blockers and other medication. I just needed some damned sleep.

</comment></comment></comment><comment><USER35> I don't know enough about this particular hardware to know. I know when I was tested for sleep apnea, the CPAP machine they suggested for me was set on a very low flow rate. A number of factors contribute to the airway obstruction in sleep apnea. One is muscle tone in the airway: too flimsy of muscle will collapse more easily. One is body fat: too much and it squeezes everything closer. One is airflow itself: if the airway is constricted just enough to create a thin slit, the airflow through it will reduce the air pressure and close it the rest of the way. Snoring is thus essentially the same phenomenon as how reed instruments produce sound. So, the idea with a CPAP machine is not to force air into your longs, it's to create enough positive pressure inside the airway to open it again and let your own lungs do the bulk of the work thereafter.

But they are _extremely_ intrusive to sleep, especially if you have a partner. A better CPAP machine _is_ needed. But I won't give them pre-order money, more because I've seen way too many bad crowd-sourcing projects than out of specific concerns towards this project.

For $3 I'll buy it on a whim and try it out. I'd try a larger one that was significantly smaller than a standard CPAP for $20, maybe even $50.

But whether or not the project is legit is kind of beside the point to me right now. Having done a lot of prototyping of my own, in both software _and_ hardware, it bothers me to see people jump directly to crowdfunding before they've even built a hot-glue-and-wires version of a prototype. Prove the concept. It's not that freaking hard.

All they say they've done is built the shell of the noseplug. They haven't any idea how to get the electronics on the inside. Their FAQ page makes it sound like their understanding of cutting edge electronics comes from Popular Mechanics, or Boing Boing.

People act like hardware is so extra-special hard. It's not. It's no more or less difficult than hacking on software in your free time. The actual, core functionality of your project, whether it's hardware or software, should be possible to validate in less than a month. The rest of what it takes to turn any project into a real product will far eclipse the proof-of-concept work in the level of effort necessary. There's no such thing as "if you build it, they will come".

Okay, no, Elon Musk's Hyperloop can't be validated in a month. A brand-new, hyper-secure, microkernel operating system written in Rust wouldn't be, either. I'm not saying _all_ ideas are possible in a month, I'm just saying the stuff people typically do in the given spaces as garage inventors _are_ on the short-scale for validation.

It just takes up a little to a lot more space. But if you're dedicated, most people can find the space. I'm sure a few adults like supposedly involved in this project can rent out a small warehouse on their pocket cash together. I don't even work full-time, I live in one of the worst areas of the country for real estate prices right now, and even _I_ could scrap together the money for a small warehouse, if I had to.

It's going to be hard if you don't have any experience in hardware. Yeah, but even making a simple CRUD app is going to be hard if you don't have any experience in software. We live in a golden age of hardware development. Nearly everyone and their neighbor in the US has a garage full of tools that could bootstrap a small industrial renaissance in a 3rd world country.

Or you don't even have to buy anything, design a flat-pack vector layout in Inkscape, email it to any of the thousands of laser-cutting services in the country, tell them you're fine buying scrap material, wait a couple of days, and you can make anything the size of a breadbox for about $50.

Need more complexity? Make a 3D model in blender, send it off to any of the dozens of (and growing) 3D printing services, wait a couple of days, and you can make anything the size of an old Walkman for about $50. Seriously, don't buy your own 3D printer unless you want to get into the business of maintaining 3D printers. Outsource that malarky.

But come on, if you don't believe in your project enough to put your own time and money into it, how do you expect us to believe in it? (though, I know that isn't really stopping anyone).

<comment><USER36> Exactly, I think the success of this crowdfunding campaign speaks more to the opportunity present in improving the durable medical equipment marketplace than it does to the promise of this particular device.

</comment></comment><comment> awinter-py You guys are awesome for doing this, but are enabling a dangerous kind of startup: 1\. post bullshit to indiegogo 2\. hackernews designs it for you 3\. profit</comment>


$250k of DigitalOcean credits for YC startups - <AUTHOR> http://blog.ycombinator.com/$250k-of-digitalocean-credits-for-yc-startups <comment><USER2> Hey, full disclosure I'm the CEO and cofounder at DO. We built DigitalOcean specifically for developers at startups, SaaS and small-medium businesses concentrating on simplifying cloud infrastructure and delivering an experience that people love. Today we offer a high performing compute product with Droplet that allows running nearly any Linux workload. We also offer shared networking, Floating IPs allowing DIY load balancing, and team accounts for collaborative groups. As well as one click snapshots, automated backups, a web console, extremely friendly support, and tons of documentation that make DO a perfect fit for startups.

Our differentiators allow devs to get started faster, leveraging our UI and intuitive API to automate their deployments and scale with ease. Some of our larger customers have started with just a few Droplets in a stage/dev environment and have grown to thousands of production Droplets managed via their application.

We believe our platform is ideal for startups coming to market that need flexibility and ease of use when going through rapid feature iterations.. Our philosophy is that developers should be focusing on their applications, not managing their servers. This is baked into everything we do, including our straightforward pricing model, so that there's no need to guess what your bill will be at the end of the month.

Also our price:performance ratio is outstanding and with a static pricing model it's trivial to calculate your bill and plan ahead for growth. And we provide the same on demand utility per hour pricing that allows maximum flexibility. One click snapshots, automated backups, web console, extremely friendly support, tons of documentation make DO a perfect fit for startups.

If you'd like to consider DigitalOcean for your startup just reach out to us via [https://www.digitalocean.com/company/contact/sales/](https://www.digitalocean.com/company/contact/sales/) and we'll support you.

</comment><comment><AUTHOR> This is interesting, I'm not sure how digital ocean would be a good fit for a startup.</comment>


Virtual Music Box - <AUTHOR> http://www.windytan.com/2017/07/virtual-music-box.html <comment><USER2> For integration with DAWs, I'd recommend using the SFZ v2 format, which is an open standard, uses a plaintext file for the metadata to specify how WAVs are mapped to the keyboard, has many extra features like release samples and the ability to repitch as needed to avoid the sox conversion, and is widely supported with VST and AU plugins. For the wind-up sound and whirring noise, you can map those to keys outside of the range of the music box (C2 and C#2 for example).

[http://www.sfzformat.com/index.php?title=Main_Page](http://www.sfzformat.com/index.php?title=Main_Page)

</comment><comment><USER3> Meta Note: If you don't read Oona's blog regularly, you're really missing out on some great stuff. Even if you have little interest in sound processing, her discovery processes are more than worth the price of admission.

Here is just one great example of many:

[http://www.windytan.com/2013/11/decoding-radio-controlled- bu...](http://www.windytan.com/2013/11/decoding-radio-controlled-bus- stop.html)

</comment><comment><USER4> So cool, thanks for sharing!!</comment>


App Engine 1.4.2 SDK - API Updates and Additions Edition - <AUTHOR> http://googleappengine.blogspot.com/2011/02/app-engine-142-sdk-api-updates-and.html <comment><USER2> Looks like the biggest change is the addition of Django 1.2 (previously it was only 0.96). What are the key features that Django 1.2 offers?

Still waiting for SSL for custom domains, that's by far the biggest gap in GAE's feature set.

<comment><USER3> New admin interface, and lots of API changes (unicode, forms, etc.).

<comment><USER4> I believe the admin interface doesn't work on AppEngine though :(

</comment></comment></comment><comment><USER5> Is anyone using the XMPP API for anything?</comment>


Al Zimmermann's Programming Contests - <AUTHOR> http://azspcs.net/ <comment><USER2> is the current problem (or earlier ones) complex enough for this to be more than a hardware contest?

<comment><USER3> This one seems at first glance to be complex enough that you will not see any perfect solution (NP-complete?)

I would say it's more than just a hardware contest but if the approaches are similar enough having enough time and hardware may make a difference...</comment></comment>


Low-tech air filter for bad air quality emergencies - <AUTHOR> https://techsparx.com/blog/2018/11/ghetto-air-filter.html <comment><USER2> MacGyver Recipe: Box Fan + Ordinary Store Bought HVAC Air Filter + Duct Tape = _Low-tech air filtration device_.

Excellent idea!

(Also, wild guess here, but wetting the filter might slightly decrease the particle size of air contaminant permitted through; that is, it might slightly increase the efficacy of the filter -- but without testing against real world air polutants in real world scenarios, I wouldn't know that for a fact...)</comment>


New Yorkers: help me defeat the evil NYC real estate market - <AUTHOR> http://www.rentenforcer.com Hi guys
I am an NYC based hacker who has had enough of dealing with the horrible process of finding and getting an apartment.  One of the major issues you have is that you can only trust what the broker tells you to be true, ie "trust me, this is a good deal."
I have a solution: collect the rents of people in the city, and get a general idea of how yours compares (or how much you should be paying for a neighborhood if you are planning on moving).
Right now the app is very simple: it's just collecting data.  Ultimately I'm not 100% sure how I'd use the data, but it would likely be open/free via an API etc. on top of my product.  One vision I have is something like a Yelp.com but for real estate.
I am open to your ideas, and I'd love to get any feedback about the idea you have (I know the site itself isn't much).  If you are a New Yorker, I'd really appreciate if you could take 30 seconds and fill out the form.
Thanks! NYC RentEnforcer <comment><USER2> This is a good idea, but maybe there's a way for you to display some data before signing up? Right now, there's nothing on the site at all except for the form requesting my information. After I submit it, there's a message there's not enough data for my address, and a request for email. At this point, it would be helpful to see what exactly I'm signing up for.

Maybe examples for different addresses, or average data per neighborhood? I recently was looking for a new apartment, and I found this very useful: <http://www.tregny.com/manhattan_rental_market_report>

<comment><AUTHOR> I definitely hear you - this is actually just an idea I had last night and just wanted to get some data. The response has really been pretty decent (I've got about 150 pieces of usable data).

My next step is to figure out exactly how to use the data. I will likely start with neighborhood pages, and move on to individual building pages once the data gets dense enough.

But I would love to hear your thoughts on product ideas - what info would you like to see? What comparisons/analytics on the data you know I have?

Thanks a lot for the feedback! RentEnforcer

<comment><USER3> Well, as your friendly neighborhood real estate agent: What do you feel is so "evil" about the NYC real estate market, aside from using it as a provoking headline?

Apartment prices depend on the move-in date - an apartment may be rented at significantly less than its current market value if the tenant has been there for 10 years, while someone who just moved in to the identical floorplan will be paying quite a bit more. Comparing this smattering of prices is unhelpful, and is exactly why rental reports like the one linked above are based on average and median prices for apartments currently on the market or recently rented.

<comment><USER4> "What year did you move-in" is a good question to add to this page.

</comment></comment></comment></comment><comment><USER5> Like the idea. Think you need to figure out a way to get people who are happy to submit data. Like Glassdoor, I'd guess that the unhappy are more likely to provide data. Especially true for folks in the city who feel they have a great deal - why would I advertise that and tell others about that?

Beyond that, didn't like the fact that I provided data and got a "no data available" page. I understand your building up the dbase, but it didn't leave me with a great feeling (not a biggie). Perhaps you could show me some data for close by areas so at least as a user, I feel like I benefited somewhat.

On amenities, would add -- Doorman building

At some point, you could perhaps mash up data you get about buildings with a lot of the data NYC has opened up about the city as part of its gov2.0 efforts. This way, you can provide a sense for the "value" of an apartment alongside stats like average income of neighborhood, crime rates, etc.

But of course, building up your dbase is priority one. Good luck.

<comment><USER3> > At some point, you could perhaps mash up data you get about buildings with a > lot of the data NYC has opened up about the city as part of its gov2.0 > efforts. This way, you can provide a sense for the "value" of an apartment > alongside stats like average income of neighborhood, crime rates, etc.

Already got some heavy competition in that area: <http://nyc.everyblock.com/> <http://streeteasy.com/nyc> <http://www.trulia.com/>

</comment></comment><comment><USER6> I love the idea, finding an apartment in this town is a harrowing experience. It's even worse for newbies who don't know the market and often get stuck with overpriced apartments like the ones Jakobson Properties rent out. What do you plan on doing with the data you're collecting?

//edit: On your amenities list, you might want to add a field for duplex apartments.

<comment><AUTHOR> I'm not 100%, and I turn to HN for ideas. I will likely be providing a free search/compare service for apartment lookers, and eventually charge the landlords to manage their page or something. But any ideas you have I'd love to hear. Ultimately I'd like to make some sort of API to the data (ie: destroy the gatekeeper to this information that makes the market so hard for consumers), but that will likely be secondary to the main product.

<comment><USER6> I'd suggest taking the trends from TREGNY (but not the actual values, as they are skewed high). Then taking scrapes from craigslist, leaving off the outliers, and then fitting those values to the trend curves and adjusting based on the input you get from your form. There's a bunch of data out there already, might as well use it in conjunction with what ever you're doing right now.

</comment></comment></comment><comment><USER7> Great idea but do this for future-proofing while you still can:

<http://nyc.rentenforcer.com/>

then one day you can grow, ie:

 _chicago.rentenforcer.com_

 _boston.rentenforcer.com_

etc.

for now you can map _www._ to _nyc._ to keep inbound links

</comment><comment><USER8> If you want to help New Yorker's, you're going to have to make an option for "0" bedrooms, as that is quite common around here :-).

<comment><AUTHOR> Hmm...I figured those people would select 1 BR and hit the Flex/Studio checkbox, but I guess that's not so clear? Maybe I should make it 0/Studio -> 5+ and then change the Flex/Studio checkbox to just Flex? Thoughts?

<comment><USER9> I had a hard time deciding whether to check the "Flex" box or not. I live in a 1 br/sort of 2br and I was trying to decide if it should be 1/Flex or 2/Flex. Should the number of rooms you choose include the sort-of/flex BR?

</comment></comment></comment><comment><USER10> "Where do you want to live?"

It would be nice to be able to put in neighborhoods instead of street + zip. E.g., "Upper West Side."

</comment><comment><USER11> Where's the London version? ;-P

<comment><AUTHOR> Just started this project this morning, but the goal is soon! Once I get a decent product working for NYC it shouldn't be difficult to branch it off into other cities.

<comment><USER12> Also, every friend I have who tried to rent an apartment in São Paulo either failed or ended up with something wildly overpriced. If you could make this generic enough to use in other countries/cities it'd be great.

</comment></comment></comment><comment><USER13> Am I being a nitpicking nerd or does "(100% anonymous & confidential)" seem wrong when asking for my street address and probably logging IP and possibly other data?

I haven't tried to use it but what I've read in the comments here you also ask for email address.

Confidential, maybe. Anonymous, unlikely.

<comment><AUTHOR> Wrong and wrong.

I don't log any data other than the date besides what you put in the fields. I also don't connect the email address to the listing, it just goes onto a mailing list.

For now it is confidential, though I'm not sure how to reconcile the idea of an API with confidentiality - even when anonymity is involved. Perhaps I should just change it to 100% anonymous?

<comment><USER13> The only reason I even cared about it was because you stated it. It made me think this information SHOULD be kept private and think twice before letting it information out.

Does that message even need to be there? Is anyone concerned with it? Might be be better to put the message at the bottom instead. Those who care will look for a statement like that and others won't be distracted.

</comment></comment></comment><comment><USER14> If I've never lived in NYC, or am planning to move there, there is no way for this to be useful to me. Let us see the data once you've gotten enough without putting anything in. Or do it glassdoor style where you only partially see data.

<comment><AUTHOR> Definitely agree, this will be the next step. The project is about a day old, so I'd love to hear your thoughts on what directions it should go in.

</comment></comment><comment><USER15> Yes, there's a problem with this UI. People who are curious will plug in any data just to see the results. That will result in your data being 'polluted'.

</comment><comment><USER16> Add dishwasher to the list.

</comment><comment><USER17> 1\. opensource it (the code, so people can build their own website) 2\. provide an api

You'll soon face spam issues though. what's your spam strategy?

<comment><AUTHOR> Likely community moderation.

</comment></comment><comment><USER18> Couldn't you scrape craigslist at least for some basic information about each neighborhood?

<comment><AUTHOR> I easily could - the whole point is to avoid taking the information from the marketplace. The prices on craiglist are borderline fraudulent, and are meant to get you into the broker's office at which point they inform you "oh sorry that apt is gone, but here are 5 more that aren't as nice and twice the price!"

<comment><USER3> > The prices on craiglist are borderline fraudulent

The most attractively priced apartments advertised on CL are on there because they _are_ great deals. There are thousands of people looking for the cheapest apartments, and when someone rents it, that means 999 other people get to hear "I'm sorry, that apartment is gone." Obviously I understand the frustration, since I've been on both sides of those conversations, and there _are_ some brokerages that put out shady ads, but nearly all rentals are on the market less than a week, and smart landlords price their apartments so well they are rented within a day - just because apartments get rented is not evidence of a mass conspiracy.

<comment><USER19> I've actually had "ok" experiences finding apartments on Craigslist. However, here are practices that bug me:

\- brokers and rental companies ALWAYS post in the "by owner" section. I've had agents from Citiapartments actually pretend to be the "owner!"

\- brokers post in the "no fee" section but there are always fees.

\- no photos... because everything that's a decent deal is also a dump.

\- "Net Effective" rent prices in the listing. It's listed at $1700 but that's the "Net Effective" rent not taking into account your 2 months free after 14 months and waiving the fee we didn't tell you about which means that you're really sending us a check for $2150 every month but really, trust us, it's only $1700.

<comment><USER3> Brokers advertising as "by owner" should be reported, and if fee apartments are advertised in "no fee," those should also be reported. (Honestly, management companies are allowed to split off and have their own brokerage, so that they collect fees by renting the apartments they already own, and in that case they would advertise in "by owner," but it sounds like you were speaking of something different.)

Not having pictures is directly related to how fast apartments are rented - sometimes it's simply not reasonable or possible to gain access and go take pictures of an apartment before it is rented.

Net effective is slimy, but not prohibited, as long as it's labeled properly.

For what it's worth, I never advertise without photos and have never used net effective prices, which is my personal decision, but it still bothers me when people extrapolate from a few bad ads or ads they think are misleading and then disparage the entire industry. The real CL scams are much worse than what people are typically paranoid about real estate agents doing behind the scenes.

<comment><USER19> It's not a few bad ads, it's like every third ad. I went through 15 experiences like what I described above and gave up and found my current place through a friend. I don't find it that "slimy." I just figure this is New York and that's how everything works... there's always some middleman trying to screw you. It's what the entire economy of the city is based upon.

As far as I can tell, almost every price listed by a management company for an apartment in a new development is "net effective," whether they list it as such or not.

<comment><USER3> It's disappointing to hear that you had such a bad experience, and if you're searching at certain price points I can see how you'd hit a bunch of brick walls when trying to find an apartment - having inside knowledge, whether it's through a friend, working directly with a management companies, or having a broker who knows what you are looking for, is always the best way to find a place.

> As far as I can tell, almost every price listed by a management company for > an apartment in a new development is "net effective," whether they list it > as such or not.

You're right - new developments and management companies are the ones who thrive on advertising net effective prices. They are not officially "brokers," so they are not held to the same guidelines and restrictions that brokers are, and they operate in an uncomfortable gray area when it comes to advertising on CL.

</comment></comment></comment></comment></comment></comment></comment><comment><USER20> This has fantastic potential. Good work!</comment>


Ask HN: Bandwidth of a station wagon full of tapes hurtling down the highway - <AUTHOR> I have encountered this famous quote and I must say I love it:
Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway.
Now the question is, what the bandwidt is? Speed limitation 130km/h with LTO-8 compressed tapes.
:) <comment><USER2> there was also the sneaker net, it was faster to grab a cart of mag tape and/or punchcards and take a walk down the hall

[https://en.wikipedia.org/wiki/Sneakernet](https://en.wikipedia.org/wiki/Sneakernet)

>> Similarly, as of 2019 the highest capacity backup tape format available is LTO-8, with a capacity of 12 TB. If a tape of this capacity were sent by overnight mail and were to arrive around 20 hours after it was sent, the effective data rate would be 1328 Mbit/s. With networking technology, this magnitude of speed over this distance would be very difficult to attain without a costly dedicated connection as one would likely need to use several hops and have a connection that is not oversubscribed. <<</comment>


Inside FastBoot: the road to server-side rendering - <AUTHOR> http://emberjs.com/blog/2014/12/22/inside-fastboot-the-road-to-server-side-rendering.html

<comment><USER3> > Your Ember app will behave no differently than server-rendered apps when it > comes to search engines, mobile users, cURL, or users with JavaScript > disabled.

How are Javascript disabled users going to use the app? Unless the app consists text and links, all interaction like submitting a form is usually coded with the idea that an ajax request will be made instead of a form submission triggering a page refresh.

react-router is React's most popular router component (which is inspired by Ember's routing system) just delivered a solution for server-side rendering a few weeks ago. My app can now deliver the fully rendered html from the server and the server also can "fetch the models" when preparing the html. However, if the user is quick (or their internet connection is slow) and tries to submit a form before React had a chance to "rehydrate" it won't work. Sure links work just fine but none of the bits that require my app to be running will work which is significant portion of most applications designed around React, Angular, Ember, etc.

For now, either we go back to spinners (which won't stop spinning if you've got JS disabled) or design the whole app with JS-disabled users in mind which would mean a lot of duplicate effort by having two possible endpoints for submitting forms; ajax-returning endpoints and traditional POST request endpoints which would return a redirect or a full page of html with validation errors included.

<comment><USER4> I have form submission and redisplay with and without JavaScript on the client working with my React forms library (newforms) and react-router.

The server version funnels POST bodies through the same willTransitionTo hook that the client uses for form submisson. Superagent is used within the hook to attempt submission to the same API route in both environments and redisplay is done by rendering a full page on the server, or emitting errors from the API via an EventEmitter on the client, all with the same React component. User input, validation errors and any other data required to render the server version are made available for the client version to rehydrate from at any time it's able to.

There are still some bits which feel (and are) hacky, but it works - <USER2> here:

[https://github.com/insin/newforms/issues/55#issuecomment-677...](https://github.com/insin/newforms/issues/55#issuecomment-67756422)

<comment><USER3> Wow, really. That's awesome!

My initial happiness when I got server-side rendering working complete with ajax calls on the server was short lived once I realized none of my forms worked until React had chance to load and run.

I'm really glad someone else out there has noticed this issue and is attempting to tackle it.

Although I was hoping I would still have control of how I build my forms while I do it. Do you think it would be possible to separate the form submission and redisplay functionality from the widget library part of newforms?

<comment><USER4> The important part for making it isomorphic is the data flow - you could use any component which can populate its form fields and error messages from props on initial render. The express middleware [1] which uses your react-router routes just handles getting data to the right place.

[1] [https://github.com/insin/isomorphic- lab/blob/master/src/reac...](https://github.com/insin/isomorphic- lab/blob/master/src/react-router-middleware.jsx)

</comment></comment></comment></comment><comment><USER5> Thinking out "loud":

1) How does transparent server-side rendering of Ember change the role of what was the server-side app before? Are you now managing a separate server environment for your Node Ember application?

2) Does this affect the ability to distribute your frontend over a CDN? Is this common practice for current Ember applications?

<comment><USER6> > How does transparent server-side rendering of Ember change the role of what > was the server-side app before? Are you now managing a separate server > environment for your Node Ember application?

Our goal is not to make Ember an "isomorphic" server-side framework. You would still have your regular backend responsible for generating JSON (whether that's Node, Rails, Django, .Net, etc.), and run an Ember app alongside it in the same data center to generate your HTML. In terms of server architecture, you've already separated HTML generation from JSON endpoints (for Ember, but possibly also for other clients like iOS, Android or API endpoints), and this continues that separation.

The benefit is that the HTML generation that lives on the client in order to make subsequent navigations fast can also live on the server to make initial boot fast.

<comment><USER7> Wouldn't this add processing latency? You'd have to have your original backend, it'd send to Node+Ember, then finally it responds to the client.

</comment></comment></comment><comment><USER8> SEO is my main concern.

Now I will definitely sift to javascript for server and client development.

Good Job ember.js team.

</comment><comment><USER9> Let the SEO-friendly client-side JavaScript framework wars begin!

</comment><comment><USER10> Not to be confused with the Android FastBoot.</comment>


Indian startup develops low-cost wind turbine that can generate 5 kWh each day - <AUTHOR> http://theusualroutine.com/2016/11/01/cost-iphone-can-now-buy-wind-turbine-can-power-entire-house-lifetime/ <comment><USER3> Here's a critique of small wind turbines. Basic problems:

\- Unless you're in a fairly windy location, wind turbines are useless. Most places aren't windy enough. Power goes up as the cube of wind speed.

\- Tower height is a big deal. You have to go up about 80-100 feet in most places to get good wind. Also, wind turbines on buildings are useless - <USER2> building disrupts the airflow too much.

\- A small wind turbine is nowhere near as reliable as the average car. So you need to be able to fix something that's 100 feet up. Tilt-up towers are a good thing.

\- The turbines themselves aren't that expensive. Here's one for $450 from Wal-Mart.[2] It's nominally rated at 450 watts. It takes 28 MPH wind to get full power. That's not common.

[1] [http://www.solacity.com/small-wind-turbine- truth/](http://www.solacity.com/small-wind-turbine-truth/)

[2] [https://www.walmart.com/ip/45798215](https://www.walmart.com/ip/45798215)

<comment><USER4> all going points. Also they kill birds. I read somewhere that the small ones kill more than the big ones - small ones spin faster?

the project seems a little misguided. India is a sunny place. Never been to India during monsoons, but if it is like costa rica, it'll rain in the mornings or at night. don't get too many overcast days.

<comment><USER5> The number of birds killed by turbines is extremely small (hundreds of thousands [0]) compared to the number of birds killed by cats (hundreds of millions to billions [1, 2]).

[0] [http://www.audubon.org/news/will-wind-turbines-ever-be- safe-...](http://www.audubon.org/news/will-wind-turbines-ever-be-safe-birds) [1] [https://www.sciencenews.org/article/cats-kill-more-one- billi...](https://www.sciencenews.org/article/cats-kill-more-one-billion- birds-each-year) [2] (slight counterpoint to 1) [http://www.npr.org/sections/13.7/2013/02/03/170851048/do- we-...](http://www.npr.org/sections/13.7/2013/02/03/170851048/do-we-really- know-that-cats-kill-by-the-billions-not-so-fast)

<comment><USER3> It's a big problem only in a few narrow corridors. The California coastal range has a few passes that are both migratory bird routes and good wind turbine sites for smaller turbines. Pacheco Pass is particularly tough, with row after row of older, smaller wind turbines (mostly 65KW) going on for miles. It's like a Veg-O-Matic chopper for migratory birds.

</comment></comment></comment></comment><comment> semi-extrinsic Can someone find another source for this? Because the one up now is hardly what you'd call credible:

[http://theusualroutine.com/2016/05/24/russia-orders-us- tell-...](http://theusualroutine.com/2016/05/24/russia-orders-us-tell-world- aliens-will/)

<comment><USER6> Hmm, yeah it did get a write up here: [http://economictimes.indiatimes.com/news/politics-and- nation...](http://economictimes.indiatimes.com/news/politics-and-nation/avant- garde-innovations-develops-wind-turbine-to-light-up-homes-at-a-fraction-of- power-bills/articleshow/53015680.cms)

Here they seem really hard to be proving themselves as "credible" through association but light on actually proving out the product.

</comment></comment><comment><USER7> Real-world tests of small wind turbines in Netherlands and the UK

[http://www.theoildrum.com/node/6954](http://www.theoildrum.com/node/6954)

<comment><USER8> Interesting article. From 2010 though, so I wonder if prices have changed by now, but still relevant.

Edit: Main takeaway:

> close to the test site stands a (relatively) large wind turbine with a rotor > diameter of 18 metres. [...] It can power 42 Dutch households. [...] it > delivers almost 20 times as much energy [as the small ones]. This brings the > cost down to 4,523 euro per household, which is 8 times more economical than > the best performing small wind turbine (and 45 times cheaper than the worst > performing small wind turbine).

</comment></comment><comment><USER9> I am curious to know the cost of maintenance. Industrial sized equipment is subject to severe corrosion [1], I am not sure if the cost is really one time.

[1] [http://www.financialexpress.com/archive/corrosion-india- losi...](http://www.financialexpress.com/archive/corrosion-india-losing- rs-152-lakh-crore-annually/247576/)

</comment><comment><USER10> Smells like BS to me. Lots of marketing boilerplate about having a "green heart" and the importance of clean energy, no hard data or technical details, no discussion of competitors or what their advantage is over other wind companies, the product is "coming soon" but there's no hint of where they'd get the necessary capital and manufacturing equipment.

As a friend once said: "Nobody stops you from making a press release. A 'project' is a series of documents and sometimes people, not always or typically a powerplant..."

</comment><comment><USER11> Good luck to them but given the intermittent nature of wind, the main problem with wind energy is storage not the turbine. So a turbine like this, which is probably rated at 500 Watts or so, must be coupled with a battery pack like the Tesla's Powerwall. Even then, 2-5 kWh is not significant. The power consumption of a typical refrigerator 1-1.5 kWh/day.

</comment><comment><USER12> the major question is how would a household pay a cost of an iPhone (around INR 50,000) if they can't afford electricity. I know that I sound cynic but that's the truth in India. Rural areas which lack electricity mainly do so because of lack of enough demand that can pay for the electricity. There are NGOs/Non-profits like 'Barefoot College' providing solar-lanterns which IMO is a better way forward: Empowering people by enabling them in making those lanterns which in turn light their houses up. The cost of lantern is factored in the labor work they do in making them.

<comment><USER6> No reason we couldn't provide micro-loans or wind turbines in the same way we have done for solar lanterns and such with partners like Barefoot.

<comment><USER12> Yes that's the model I think can solve the electricity problem in developing/poor countries like India, Africa, etc. Through micro-loans and labor-conversion-to-product/services.

I for one do not believe even 1% in giving subsidies here and there to solve such problems because they are just temporary, gives false-hope and inflate expectations that problems are being solved but in reality they are not.

</comment></comment></comment><comment><USER13> > a low-cost wind turbine that can generate 3-5 kW hours of electricity every > day

I'd say it's for a very narrow definition of "a house":

[https://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3](https://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3)

I guess it could work in India, but households in most developed countries spend much more energy:

[http://shrinkthatfootprint.com/average-household- electricity...](http://shrinkthatfootprint.com/average-household-electricity- consumption)

BTW, much better article here:

[http://economictimes.indiatimes.com/news/politics-and- nation...](http://economictimes.indiatimes.com/news/politics-and-nation/avant- garde-innovations-develops-wind-turbine-to-light-up-homes-at-a-fraction-of- power-bills/articleshow/53015680.cms)

<comment><USER14> In the context of the article - India - it seems spot on.

Additionally, energy use in western homes has fallen dramatically in recent years. We've gone from 100W bulbs to LEDs and from big vacuum cleaners to small robots and even fridges, freezers and washing machines have been using less and less each generation.

Hopefully electricity use will pick up again slightly as we all start charging our cars at home, and that will be a good thing from the total energy usage and environmental perspective.

PS you edited your post and added all those links and mention of India only after I replied ;)

<comment><USER13> > PS you edited your post and added all those links and mention of India only > after I replied ;)

It was like 5 seconds apart. We probably wrote at the same time ;)

</comment></comment></comment><comment><USER15> Buy a solar powered fan and point it at the wind turbine. You are now covered for 2 cases. Wood burner for 3. What else?

Modular power from multiple sources is where the gold is.

</comment><comment><USER16> I Know This Is Off-Topic But Any One Else Hating The Usage Of Capitals In The Title?

<comment><USER17> Like it or don't, it's standard Title Case.[1]

[1] [http://www.dailywritingtips.com/rules-for-capitalization- in-...](http://www.dailywritingtips.com/rules-for-capitalization-in-titles/)

<comment><USER16> Standard? I don't really feel that this blog persuades me that it is a standard. It also adds another style to it, which is even more ridiculous! My mind puts emphasis on words with capitals, reading the title makes me bounce up and down like a carrousel with my "inner dialog".

<comment><USER17> Yes, standard[1]. I was looking for a direct reference to the AP style guide but didn't find one in a quick search. Here's another reference guide though.[2]

[1] Take a look at the headlines: [http://www.nytimes.com/](http://www.nytimes.com/)

[2] [https://www.bkacontent.com/how-to-correctly-use-apa-style- ti...](https://www.bkacontent.com/how-to-correctly-use-apa-style-title-case/)</comment></comment></comment></comment>


ASD-STE100 – Simplified Technical English - <AUTHOR> http://www.asd-ste100.org/ <comment><AUTHOR> Turns out that the standard is freely available, but involves filling out a form in an Excel document and emailing said document to them to get your free copy...

Or you can look here: [https://robertobertuol.com/wp- content/uploads/2018/08/ASD-ST...](https://robertobertuol.com/wp- content/uploads/2018/08/ASD-STE100-ISSUE-7.pdf)</comment>


Rare King James Bible First Edition Discovered at Drew University - <AUTHOR> http://artsbeat.blogs.nytimes.com/2015/12/04/rare-king-james-bible-first-edition-discovered-at-drew-university/?module=WatchingPortal&region=c-column-middle-span-region&pgType=Homepage&action=click&mediaId=wide&state=standard&contentPlacement=3&version=internal&contentCollection=artsbeat.blogs.nytimes.com&contentId=http%3A%2F%2Fartsbeat.blogs.nytimes.com%2F2015%2F12%2F04%2Frare-king-james-bible-first-edition-discovered-at-drew-university <comment><USER2> I guess I am more excited by the idea they have so many books that are not currently cataloged. There to be thousands of similar collections around the world. How much history do we miss out on simply because it now collects dust, the tech is there all we are missing is the need and money

<comment><USER3> It is speeding up with digital storage.

Who knows what those Zip drives has on them?

<comment><USER4> Well, since magnetic media has a very finite lifetime, you don't have much longer to worry about Zip disks -- they'll all be unreadable soon.

Which brings me to another fun story. My girlfriend runs a book conservation lab, and she was wondering if she should try to read the bits on a floppy disk associated with a book on numerical methods -- it costs $$ to try to read the disk, and given the age, it was unlikely to work. I know one of the book authors, so I told her I likely could probably find a copy of the software on the Internet, if she found some pages that listed the names of the software functions. Turned out that it was a copy of LAPACK, which is available at NETLIB. Only one checkin to the code since the book was published in 1986...</comment></comment></comment>


Ask HN: What makes a blog(personal)a good blog? - <AUTHOR>

How do you differentiate between a good blog(that you like to follow) and one that isn't good enough? What kind of information you look after in a blog?<p>Also, what are your favorite blogs? <comment><USER2> Unless you're a great writer, keep things short and snappy. It's really hard to hold a reader's attention.</comment>


Ambitious New Anti-Aging Trial in Humans - <AUTHOR> https://joshmitteldorf.scienceblog.com/2018/01/19/ambitious-new-anti-aging-trial-in-humans/ <comment><AUTHOR> _What we need is a ... a middle-aged billionaire angel investor who is thinking clearly about his own destiny a decade or two down the road._

I gather HN harbours some of them.

<comment><USER2> The idea that death is ignoble is starting to propagate more widely. I actually think it's a _more_ popular idea within younger cohorts. Counterintuitively.

</comment></comment><comment><USER3> There are a lot of people thinking about beneficial factors in young blood and harmful factors in old blood. Some are looking at period apheresis of blood to remove harmful factors, some are investigating transfusions, some looking at delivery of factors directly.

I don't see this area of work as a useful way forward to major impact on human aging and life span, though it will no doubt increase understanding of the way in which metabolism reacts to the causes of aging as they increase. Like much of what goes on in the research community, it is an effort to tinker with secondary and later aspects of aging. Changes in factors in the blood are not the cause of aging, they are the consequence of cellular reactions to the causes of aging. So this sort of work is changing the oil and cleaning the spark plugs in the hopes of small gains rather than repairing and replacing the failing engine parts in the hopes of large gains.

But that is somewhat beside the point. The important thing here is that organizations like the Society for the Rescue of Our Elders have come into being and are surveying the field for things they can do to impact aging, ways to accelerate the otherwise very slow progress of clinical translation in a field of research that is, on the whole, still pretty reluctant to actually make waves and public noise. Given who is involved in the Society, it will mean a lot of garbage in addition to the actually useful stuff like senolytics, but overall it is much better to have people actively trying to organize trials to gain evidence rather than not. That speeds up the process of winnowing out the useless, marginal projects and promoting the useful ones, on the basis of the results rather than debate over mechanisms.</comment>


How I accidentally learned Prolog - <AUTHOR> https://blog.jcoglan.com/2017/12/31/how-i-accidentally-learned-prolog/ <comment><USER2> Very nice, thank you for sharing!

I have one comment on the naming convention. Consider has_type/3 from the post. For example:

        has_type(_, true, bool).

A better name for this would be:

        term_type(_, true, bool).

or even:

        context_term_type(_, true, bool).

This makes clear what each of the arguments means, and does not limit the reading to only one direction of use. Note that we can query this also in other directions, and the predicate still makes sense!</comment>


Share your stuff with a link - <AUTHOR> http://blog.dropbox.com/?p=1138

<comment><USER2> Being able to link to a folder is a godsend. I hated having to share a folder (editable) when I needed to send someone many files.

However, does this now deprecate the Public folder? I thought that was one of Dropbox's best features: knowing only things in the Public folder were publicly-accessible (with a link)—and more importantly, that files located anywhere else were completely private and NOT web-accessible at all—was easy to grok and explain.

I worry that as Dropbox moves toward its stated goal of becoming the "file system for the Internet" that they will give up the focus on syncing our private files in exchange for the allure of allowing every site and app to read and write from one's Dropbox. That's a worrisome future, indeed.

<comment><USER3> I agree. I actually read your comment an hour ago, thought nothing of it, then just now tried to send a file to someone, and realized immediately how important this is.

What would be really great is to have an easy view for all files that are not private (or all files that are link-shared, etc., since there are three tiers of privacy in the Dropbox world). On the web interface, this would be easy, but I do most of my work on the command-line, so it seems the easiest way for them (or anyone) to implement this would be through links.

However, I know that Dropbox has had (still has?) issues with treating symlinks properly, so I'm very hesitant to write a script to handle this myself.

As it stands, though, I'm very concerned about this. I've used Dropbox for years, and I've accumulated so many files and folders there - I could do some spring cleaning, but most of it is actually stuff that I want to be able to access remotely. Right now, I know that everything is private, except for the shared folders, which I always name "shared_ _" by convention. Pretty soon, that won't be the case, and not having a clear system for this makes me_ really* uneasy, because I know that human error is the number one cause of security/privacy breaches.

<comment><USER4> Wonder why this reply is dead?

\---

ivankirigin 19 minutes ago | link [dead] You can view all the links you've made here: <http://dropbox.com/links> Also, when something is linked, there is a link icon on the right side of the file browser on <http://dropbox.com/home>

<comment><USER5> I posted the comment twice because the parent was posted twice. <http://news.ycombinator.com/item?id=3879016>

My guess is a bot killed it thinking the duplicate post was spam. No big deal

</comment></comment></comment></comment><comment><USER6> Good idea poorly executed. Serving a html page but having a media file extension at the end is a bad idea.

For example <https://www.dropbox.com/s/yq9fyyh794qvghv/IMG_0146.JPG>. You can't embed it in an img-tag. Other software which tries to embed or handle it as an image fails. Even worse: non-tech people you're trying to help here have no idea why: "But it's a .jpg!".

Dropbox just put a layer between me and the data and there's no easy way around it.

<comment><USER7> The extension thing is a valid critique; but the "layer" as you call it is just a main part of their business; remember, they are in the file sharing business and _not_ in the file hosting/CDN business.

</comment></comment><comment><USER8> Feeling a pressure from Cubby I take.

Sharing anything with a link has always been LogMeIn's thing, and their Dropbox clone (called Cubby and released into beta last week) also has it. But you know what else LogMeIn's stuff has that Dropbox doesn't? Client-side encryption. I wish Dropbox reacted to _that_.

[0] <http://b.logme.in/2012/04/18/introducing-cubby/>

</comment><comment><USER9> This feature was there before, you could enable it for your account by visiting <https://dropbox.com/enable_shmodel>. This gave you the context menu in the desktop software as well as the buttons in the webview. Also, you could create links to anything you wanted already in the Android app.

<comment><USER10> Yeah I was just about to say this, I thought it would have been common knowledge (at least for HN folk).

</comment></comment><comment><USER11> Might be asking to much, but is it possible to get a direct link to the file?

Otherwise programs like HipChat are unable to auto-embed the photo, because its HTML dressed as an image. For example: [https://www.dropbox.com/s/caha7e5v0js24mj/dropbox-hipchat- em...](https://www.dropbox.com/s/caha7e5v0js24mj/dropbox-hipchat-embed.png)

I'd be happy to add a query string manually, i.e., [https://www.dropbox.com/s/caha7e5v0js24mj/dropbox-hipchat- em...](https://www.dropbox.com/s/caha7e5v0js24mj/dropbox-hipchat- embed.png?img)

Imgur.com does a good job with this.

<comment><USER12> Dropbox has pretty harsh bandwidth limits for files that are hosted publicly, mainly to avoid becoming a cheap & lazy webserver for everyone to use. They additionally have the difficulty that the photo could change at any moment -- so photo URLs from their CDN have all this complicated versioning:

[https://photos-1.dropbox.com/pi/2048x1536/UoBdS4hHgypeXF5Ge8...](https://photos-1.dropbox.com/pi/2048x1536/UoBdS4hHgypeXF5Ge8K-qTJC2aSdY1wD8jeCaTgYI3I/3717712/1335286800/eb87d20/dropbox- hipchat-embed-smaller.png)

I guess my point is that it would be great, but you can have imgur or Dropbox -- not both.

</comment></comment><comment><USER13> I was recently speculating that Dropbox is the new Facebook [https://plus.google.com/109940267018696224506/posts/HPzzXpZh...](https://plus.google.com/109940267018696224506/posts/HPzzXpZhkWU)

<comment><USER14> Interesting that people are doing this, but most people use Facebook for storage/sharing second, for social/commenting first. It's not about the photos, it's about the comments attached to the photos. And about the status updates and wall posts and all the other communicative stuff.

Email doesn't handle that, because email doesn't let interested observers chip in. One-to-one has its drawbacks.

<comment><USER13> that's true, I guess it would only take Dropbox to add commenting on the sharing pages they now create. But it's mostly about the perms for me (which these shared pages don't seem to offer), I know who I share a DB folder with. And in my particular case, the comments happen over the phone, or when my family comes over, on skype and actually some to/fro email (although it's annoying when it happens there).

<comment><USER14> A comments page but also a newsfeed to track the comments happening.

It's a bit catchword-y, but I like the phrase "ambient social" to describe the appeal of Facebook in one key sense: it's not about directed conversations, it's about creating opportunities for conversations which other people might take you up on. I post a status not because I want to talk about myself, but because I'm sending out a feeler for if anybody else wants to begin a conversation. (Which is why Twitter doesn't appeal to me the same way: it's nowhere near as easy to track conversations.)

</comment></comment></comment></comment><comment><USER15> I have symlink in my dropbox folder to a few other directories on my harddrive (like pointers to My Documents, etc.) This is super useful, because I can view pretty much any small file on my computer via Dropbox.

However, this linking doesn't work well in OS X via Finder. Even though any file in My Documents is in my Dropbox, the Dropbox client doesn't detect this, and I don't have the option in the right-click menu to view the link for these files.

</comment><comment><USER16> I think the consensus is this isn't really a new feature (around since at least 06/2010), just extended to include files in any folder, not just the 'public' folder.

<comment><USER2> Well, I don't think they ever allowed you to link publicly to an entire folder, so that's pretty new.

<comment><USER17> You have been able to do it in a couple of months by using <http://views.fm>

</comment></comment></comment><comment><USER18> Minus has been doing this for awhile. It's incredibly handy to be able to share something with someone instantly and without a need to create an account. <http://minus.com/>

</comment><comment><USER17> Photo and video galleries, but no music player? Seems like they are a bit scared.

<comment><USER19> what stops you from posting a tv show or movie?

<comment><USER20> Nothing, really, but within the free space tier you can fit a ton of music but only relatively little video, so it may be less of an issue.

</comment></comment></comment><comment><USER21> Box has had this for a while and I have also been using ge.tt to do this. Nice to do it from desktop tho.

</comment><comment><USER22> When I saw the title on my feed I tought the article would be about the python simple http server. One of the most useful commands that I've ever learned: python -m SimpleHTTPServer

</comment><comment><USER23> Sounds like a shot across YouSendIt's bow.</comment>


From Pandas to Scikit-Learn – A new exciting workflow - <AUTHOR> https://medium.com/dunder-data/from-pandas-to-scikit-learn-a-new-exciting-workflow-e88e2271ef62 <comment><AUTHOR> Scikit-Learn is making a huge upgrade with its upcoming version 0.20 release. If you used Pandas as your data exploration and preparation tool before turning to Scikit-Learn for machine learning, you were probably aware of the pain points of handling string columns and doing transformations to only a subset of the data.

This process is becoming much more robust and standardized thanks to the new ColumnTransformer which allows for applying transformations separately (in parallel) to different subsets of the data. It is built to accommodate Pandas DataFrames, so you can give it column names. The OneHotEncoder has been upgraded to handle string columns.

I am very excited about this release as handling string columns was easily the worst part of Scikit-Learn and there was no canonical way of going from a Pandas DataFrame to a Scikit-Learn estimator. I also cover KBinsDiscretizer which bins numeric columns and will replace Pandas cut and qcut functions in your workflows.

Appreciate any feedback on the article.

<comment><USER2> It comes across as clear to me, though about 1/2-way through it exceeded my knowledge of the topic.

Some typos: "HoustStyle" should be "HouseStyle", "crated" should be "created", "module its located" should be "module it's located".</comment></comment>


This high-tech card is being rolled out by French banks to eliminate fraud - <AUTHOR> http://www.thememo.com/2016/09/27/oberthur-technologies-societe-generale-groupe-bpce-bank-this-high-tech-card-is-being-rolled-out-by-french-banks-to-eliminate-fraud/ <comment><USER2> The downside is that I can no longer store the card in LastPass and leave it at home, unless they have another way for me to generate the CVV.</comment>