In Germany there are millions of people in retirement age which are living alone. Approximately 30% of them come intoemergency situation because of a fall once a year. If the fall leads to bone fracture, the person isn’t able to get up by itselfand if there is nobody recognizing the situation, the fall can lead to death. For this purpose, a detector was developed,which can detect a person hitting the ground and send a signal to a family member in case of emergency. The detector isbased on an optical sensor, which makes it insensitive to outer factors like humidity or thermal drifts. Vice versa it won’tapply any electromagnetic radiation onto medical devices situated in the room. The detector uses the physical effect ofstrain-induced birefringence. The sensing lmaterial can cover a big area of an apartment, which needs to be watched by asensor. If the senor is under strain, the polarization vector of the light will change its direction while passing the materialand the system will measure an increase of light intensity after a polarizer. Therefore, different materials as epoxy andsilicones are set up and measured to characterize the behavior. To discriminate an emergency from normal everydaysituation, an algorithm is implemented, which asks for three steps to be positive ere the system triggers a signal.If the system has access to an already existing smart home-system, a signal can be activated to inform the person’s nextrelatives or even an emergency service. The systems works best, if the apartment is built newly.
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