초록 ▼

A personal alarm system includes a monitoring base station and one or more remote sensing units in two-way radio communication. An electronic handshake between the base station and each remote unit is used to assure system reliability. The remote units transmit at selectable power levels. In the abs

A personal alarm system includes a monitoring base station and one or more remote sensing units in two-way radio communication. An electronic handshake between the base station and each remote unit is used to assure system reliability. The remote units transmit at selectable power levels. In the absence of an emergency, a remote unit transmits at a power-conserving low power level. Received field strength is measured to determine whether a remote unit has moved beyond a predetermined distance from the base station. If the distance is exceeded, the remote unit transmits at a higher power level. The remote unit includes sensors for common hazards including water immersion, smoke, excessive heat, excessive carbon monoxide concentration, and electrical shock. The base station periodically polls the remote units and displays the status of the environmental sensors. The system is useful in child monitoring, for use with invalids, and with employees involved in activities which expose them to environmental risk. Alternative embodiments include a panic button on the remote unit for summoning help, and an audible beacon on the remote unit which can be activated from the base station and useful for locating strayed children. In another embodiment, the remote unit includes a Global Positioning System receiver providing location information for display by the base station.

대표청구항 ▼

A personal alarm system, comprising: a remote unit including, a navigational receiver for receiving navigational information, a demodulator for demodulating the received navigational information, timing circuits for providing precise time-of-day information, and a radio transmitter for transmitting

A personal alarm system, comprising: a remote unit including, a navigational receiver for receiving navigational information, a demodulator for demodulating the received navigational information, timing circuits for providing precise time-of-day information, and a radio transmitter for transmitting the demodulated navigational information and the precise time-of-day information; and a base station including, a receiver for receiving the demodulated navigational information and the precise time-of-day information, computational means connected for combining the demodulated navigational information and the precise time-of-day information to determine a location of the remote unit, means for storing information defining a geographical region, means for comparing the computed location with the defined geographical region and determining a positional status, the status defining a relation between the location of the remote unit and the defined geographical region, and means for displaying the location of the remote unit in response to a predetermined positional status.