Title: My son (a physics student) wrote to me to point me to a crowdsource project for a CPAP machine.<p>https:&#x2F;&#x2F;www.indiegogo.com&#x2F;projects&#x2F;airing-the-first-hoseless-maskless-micro-cpap#&#x2F;story<p>My immediate thought upon seeing the mock up was: balony, with a capital &#x27;B&#x27;.<p>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&#x2F;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!<p>And they claim a price of $3 per device…  And it’s disposable.<p>They also say they are using a zinc air battery, which has energy density of 470 Wh&#x2F;kg or .47 Wh&#x2F;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.<p>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.<p>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.
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