James Rall, of Hydroacustics Inc., of New York, explains uses for the Proteus ROV roaming ocean vehicle, used for exploration with cameras and lights. The ROV is controlled by a joystick. PROVIDENCE — Jason Cedro clicked on a computer mouse at the Rhode Island Convention Center yesterday and on the screen appeared a live, gull’s-eye view of Narragansett Bay, from a camera perched miles to the south at Beavertail State Park, in Jamestown. He clicked again to order the camera, by wireless connection, to pan the Bay, then focus more closely on a power boat motoring across the water beneath a blue sky. From the same screen, Cedro was also able to obtain a live view of the Bay’s activity from Prudence Island, another from the area around the Pell Bridge in Newport.