Heater wrote:It still makes no sense. Getting stuck in a lift because the interface is busted is no fun.
The same would be true for any other GUI application. Windows PC, Android phone, car entertainment system,... everything tends to crash one day or another, it does not make sense, but it happens...
Heater wrote:The mere fact that a question about using a Pi in a safety critical controller application, such as a lift controller, hints that the questioner is not skilled enough to be tackling such a project.
I understand your point, if the GUI software is badly written on a badly configured OS, it could be instable, and cause a bad experience for the user, but the system would still be safe, because the GUI is not part of the safety-critical controller.
The safety-critical controller must only ensure that no one is hurt in any situation (for example : do not go crazy when the UI is locked). A good safety-critical controller could also ensure that no material damage will occur. But it does not care if the user cannot use the device because of a faulty SD card.
Anyway, I don't know what are the requirements for an elevator, so I don't know if the rPi is the best platform for this kind of application.