My dear Mum has dementia and has taken to creeping quietly around the house to covertly listen outside rooms to phone calls, Needless to say, she completely misunderstands what is said and gets distressed at imaginary plots which put her into a terrible state for hours if not days.
It would be helpful to know she is there by using a sensor which transmits to a receiver to flash a light or make a discreet beep.
A remote sensing shed alarm, garage approach alarm or even some intruder alarms might work but they have a loud siren. Is there something which might fit the bill?