In the narrow and limited space of public toilet cubicles, old people may accidentally fall when they squat for too long and stand up too quickly. This will go unnoticed by people and help cannot be offered in time when an accident occurs. The Pre-warning Toilet Door is designed such that an indicator on the cubicle door will turn yellow and a buzzer will sound for help if the door is shut for more than 30 minutes.
The indicator shows up green when the toilet cubicle is available. Upon closing the door, the indicator turns red, which suggests that the toilet is occupied and kick starts a timer that is powered by an internal battery. If the cubicle door is not opened in 30 minutes, the indicator turns yellow and a buzzer will alert passers-by to knock and check if an accident has happened.