Nest managed to do the seemingly impossible with its Protect: it made a smoke detector... exciting. But what lurks within that beautiful shell? Fortunately, iFixit has ripped one wide open to find out.

There are six AA batteries, which might seem charmingly old school but they are in fact there for reliability reasons. They're enough enough for a number of years of operation, though. But, more seriously, there is some interesting stuff in there. Some highlights:

  • A pretty crazy-advanced (for a smoke detector) main board, containing the embedded optical detector which uses LEDs to sense smoke.
  • Then there's a CO sensor, which works a little like a fuel cell: carbon monoxide drives a chemical reaction that generates current proportional to the CO concentration in the air.
  • An an 85 dB horn—should be loud enough to raise the alarm.
  • There's also a straight and angled motion sensor, which will catch your waving arms when you want to silence a false alarm. See, waving at the thing can work!

All in, the Protect is reassuringly simple and straightforward in build, and easy to take apart. But you shouldn't do that, because it's a safety product, and it's best not to tamper with such things. Go read the whole teardown over in iFixit. [iFixit]