Abstract: An optical communication system includes a transmitter and at least one receiver employing a feature of an outdoor environment, or includes a transmitter and a receiver in each of multiple transceivers employing a respective or shared feature of the outdoor environment. The transmitter includes a laser emitting a beam of laser pulses having a wavelength. The transmitter encodes data into the laser pulses in the beam, and transmits the beam of laser pulses through free space of the outdoor environment and then onto a feature of the outdoor environment. Each receiver includes a line filter blocking light not having the wavelength. The receiver decodes data from the light that passes through the line filter and includes a diffusion of the beam from the feature.

Abstract: A device for signaling including a top member adjacent to a bottom member, a button adjacent to the top member, a sensor adjacent to the top member, a radio adjacent to the top member, a microprocessor board adjacent to the radio, a battery adjacent to the microprocessor board, and a switch adjacent to the bottom member. A button slot and sensor hole formed through the top member. The button is received in the button slot and the sensor in the sensor slot. The microprocessor board further comprises a light emitting diode. The bottom member has a bottom recess and a switch slot. The switch is received in the switch slot. The top member has a sensor recess and a screw hole. The sensor is retained in the sensor recess. The bottom member has a screw recess. The radio, microprocessor board, and battery are slidably received in the bottom slot.

Abstract: A device for signaling including a top member adjacent to a bottom member, a button adjacent to the top member, a sensor adjacent to the top member, a radio adjacent to the top member, a microprocessor board adjacent to the radio, a battery adjacent to the microprocessor board, and a switch adjacent to the bottom member. A button slot and sensor hole formed through the top member. The button is received in the button slot and the sensor in the sensor slot. The microprocessor board further comprises a light emitting diode. The bottom member has a bottom recess and a switch slot. The switch is received in the switch slot. The top member has a sensor recess and a screw hole. The sensor is retained in the sensor recess. The bottom member has a screw recess. The radio, microprocessor board, and battery are slidably received in the bottom slot.