zlacker

That last point is interesting. Even with an RF detector, an accelerometer may act as a cheap room bug. Heck, if automobiles use them to detect when an airbag should be deployed, why not just use them as bugs in cars? Now I'm scaring myself.

>>mclovi+(OP)
Heck, if automobiles use them to detect when an airbag should be deployed, why not just use them as bugs in cars?

AFAIK the airbag accelerometers are designed to detect much larger accelerations than e.g. the ones in a smartphone, and are thus essentially completely insensitive to anything lesser than a huge impact -- spurious airbag inflation is one of the things the manufacturers really, really don't want to happen.

Many of them are just mechanical switches actuated by a weight, with no active electronics (makes sense for such a safety device to be as simple as possible): https://www.youtube.com/watch?v=mWSlwhYyOhI

And even when not impacting anything, a car is not exactly a quiet and vibration-free environment either...

>>userbi+9l
Very good points.