LIGHT RAY ROBOT

Greymouth Evening Star, 8 November 1933, Page 3

LIGHT RAY ROBOT

MACHINE THAT SAYS “WHEN.” A machine that will “say when” in any circumstances has been produced at the National Physical Laboratory, Teddington, under the Department ot Scientific and Industrial Research, says the “Morning Post.” It is worked by a photo-electric cell on the same principle as the famous “invisible ray.” The uses to which it could be put are almost unlimited. Among them are: — The control of theatre and other queues by such announcements as “First five rows full,” “Last twenty seats,” and “House full,” the latter to be followed after a warning light by the automatic closing of the doors; the measurement of engine speeds up to the highest speeds available; and the control of factory production by cutting off conveyor belt supplies when any specified number of packages has been delivered. All these achievements and many others are made possible by. the fact that the machine can be set in advance to count up to any desired number and then “trained” to take whatever action is appropriate in the particular circumstances. Yet its original purpose was nothing more spectacular than to provide a more economical method of measuring the performance of new types of domestic electricity supply meteis when various “loads” of current weic being taken from the mains. The old method of timing the usual slowly revolving disc with a stopwatch, it was explained, involved the attendance of two trained workers if accurate results were to be secured. A one-man test was desired — and this is what the laboratory devised. A small mirror was placed on a revolving disc.' A fixed beam of light was shone in the direction of the mirror, and a photo-electric cell was so placed that once every revolution the reflected light shone upon it. The effect of this was to provide an electrical record of each revolution without touching or in any way interfering with the revolving wheel. Next, part of the mechanism of an automatic telephone exchange was pressed into service. This is the device by which vacant circuits between any two exchanges are automatically selected as soon as the caller has finished dialling the exchange wanted. This has been adapted to do the work of counting. It can be pre-set to anv desired figure. The stop-watch is started when the first signal is received from the photo-electric cell, and it is stopped again at the precise frae- ' tion of a second when the count is finished.

For direct counting—-whether of the revolutions of a wheel, of people passing through a door, or of anything sufficiently solid to block the light ray—the machine will work up to 3000 events a minute. But the robot can also be adjusted to record only every tenth or hundredth interruption of the light ray, and in this way it can be made to work up to the very highest speeds—for example, in the testing of highspeed engines. Equally it would count such relatively slow events as the lapping of a car round, a racing track. Over and above timing, the robot counter could be made to do anything

of which electrical relays are capable. It could turn on lights, shut doors, release a “canned voice,” start or stop machinery, and even operate a lottery by giving free gifts to every hundredth caller. Meantime the National Physical Laboratory has simplified an important part of its routine work —and there is satisfaction at Teddington.