US Patent 11227471 Wireless security and assistance system

A wireless system for monitoring portable articles includes a central alarm unit (CAU) comprising a programmed controller operatively associated with a CAU wireless communication circuit. At least one wireless sensor comprises a programmed controller operatively associated with a sensor wireless communication circuit for communicating with the CAU wireless communication circuit. The CAU is programmed to periodically determine distance between the wireless sensor and the CAU and operates in a programming mode and responsive to manual input commands to determine a normal distance of the article being monitored from the CAU. The CAU is programmed to define a first zone as the normal distance plus a first select amount and a second zone as the normal distance plus a second select amount, greater than the first select amount.