I have a product that is somewhat sensitive in nature that is pretty heavy and difficult to handle, but that is externally very robust, ie it probably won't show signs of being dropped.
I want the device to be able to know if it has experienced an impact and be able to refuse to work in that case.
Because the product has a long shelf life i don't really want to use a continuously powered sensor solution, especially as that could potentially be asleep and miss the impact. A passive sensor does exist, they use a steel ball on a magnet, and when a certain g is exceeded, the ball jumps off the magnet and knocks some over centre contacts apart, and those contacts don't re-join when the ball jumps back onto its magnetic base after the impact has finished. That sensor could easily be read by a simple micro controller input.
However, those sensors are
1) Large and cannot easily be PCB mounted
2) expensive for what they are
3) can potentially be reset by being disassembled and physically reset
4) do not have different tripping G in each axis, and generally have one axis where they have effectively no sensitivity
I'd love a totally pcb mounted, small, and configerable solution :-)