Abstract: An apparatus for automatically controlling the operation of a door comprises a microwave transceiver responsive to detect the movement of a randomly moving object and operative to develop a Doppler signal representative of such movement, the Doppler signal being generally sinusoidal with a zero crossing in each cycle, a strobe generator responsive to the Doppler signal and operative to develop a timing pulse upon the occurrence of each such zero crossing, a pair of integrating circuits responsive to the Doppler signal and operative to develop first and second signals of unlike polarity in the absence of the movement and of like polarity in the presence of the movement, a pair of OR gates for detecting the respective polarities of the first and second signals, a sample and hold circuit responsive to the timing pulse and operative to develop a control signal when the first and the second signals are of like polarity, and a relay driver responsive to the control signal and operative to open the door.

Abstract: A cold frame for providing an environment conducive to the growing of plants having walls and a flexible, light-transmitting cover member which is flexed to form a ventilation opening. The cover member is flexed manually or by means responsive to the temperature of the interior of the cold frame.

Abstract: A timing gate adapted to admit passengers to a chair ski-lift loading area is synchronized with the lift to allow passengers in the required number to approach crossing the path of the chairs around the lower bullwheel. At a timed interval after a chair has passed a chair operated switch, the gates open for a brief interval, a red light is turned off and a green light is turned on, and a gong is struck. After the brief interval the gates close and are locked and the green light is changed back to red. A weight operated switch may be used to prevent opening of the gates unless there are passengers waiting or the gate may open automatically after the passage of each chair. An inverted U-shaped frame has a pneumatic cylinder attached to each leg, the piston of each has secured thereto a rod-like gate projecting transversely through a helically extending slot in the cylinder 90.degree. therearound.

Abstract: A system for controlling the air and radiant temperatures, ventilation, illumination and humidity within an enclosed building is described. The system comprises a double glazed window which is transmissive to light and heat energy mounted in the wall of the building. Means are provided for measuring the net energy flow through the window and for automatically adjusting the energy flow through the window responsively to seasonal as well as weather conditions. A heat sink is thermally coupled to the building for storing some of the insolation received so that it can be released as the temperature drops in the building. The system can also include an auxiliary roof heating system. Also ventilation and humidification means for circulating and humidifying exterior air drawn into the building are provided.