Abstract: A personnel activity sensor and alarm system is provided which incorporates one or more remote personnel safety units each incorporating a multi-axis motion detector and reset timing and logic circuit coupled with a radio transmitter or transceiver. Under the command of the logic circuit, the radio automatically transmits an alarm signal and causes the circuitry to generate a local audio signal in the event of personnel inactivity for a predetermined period of time. This enables personnel assistance to be initiated without delay. A base station is also provided which incorporates a radio transceiver to which is coupled control logic circuitry for commanding transmission of radio integration and control signals to the radio receiver of the remote personnel units for acknowledgment of alert signal reception and for cancellation of the radio alarm signal to clear the radio channel for other activities.

Abstract: An ear microphone includes a bimorph piezoelectric transducer mounted on a PC board having an amplifier therein and surrounded by a helically wound spring. The piezoelectric transducer and spring are potted in a semi-soft potting compound which is formed in a shape adapted to be inserted into an external auditory ear canal to permit bone conduction to the microphone element. A cable is coupled to the amplifier through which a signal can be withdrawn for processing by electronic equipment.