US Patent 8258977 Manhole cover with signal transmitter

A manhole cover is for use with a system for transmitting data to an above surface receiver. The manhole cover includes a body suitable for covering a manhole. At least a portion of the body is formed from a radio wave penetrable material so that radio waves may pass through the body. A microprocessor is provided for receiving a signal representing at least one environmental parameter inside a manhole enclosure measured by a sensor, and for responding to the signal by directly or indirectly causing a change to a parameter in the enclosure. A transmitting element in communication with the microprocessor transmits the signal to the surface above the manhole cover. Circuitry connects the microprocessor and the transmitting element for driving the transmitting element to transmit the signal. The microprocessor may be programmed to run an energy conservation cycle, which preserves power from the power source. Any one of numerous antenna designs may be embedded in the body of the cover.