Optical switch for an automatic door

A passive optical switch for an automatic door for automatically opening and closing a door, by sensing the direction of movement of passing bodies within a sensing area, comprising:

• light receiving means having at least two groups of optical fiber cables, each group having first and second ends, the first ends forming light receiving surfaces, wherein each surface is positioned to receive light from a different portion of a sensing area;
• phototube cell converter means, conncected to the second ends of the optical fiber cables, for producing a separate indication signal, for each light receiving surface, which has a characteristic indicative of the intensity of light received by that light receiving surface;
• and
• direction discriminator circuit means for receiving said separate indication signals and for producing a control signal for driving an automatic door in response to a passing body being sensed in one sensing area portion after being sensed in another sensing area portion, as indicated by the characteristics of said separate indication signals.