System for safeguarding a person from an autonomously operating machine. The system comprises a safety controller for asserting control over the autonomously operating machine based on an input signal generated by a body-worn. The body-worn device comprises safety means for ensuring failsafe locking and arrangement of the body-worn device on the person in a predefined manner. Furthermore, the body-worn device is configured to generate the input signal only when the body-worn device is locked and arranged in said predefined manner.