A device for allowing the remote-reading of a utility meter having circular dials. The device includes an array of phototransistors for each circular dial of the utility meter. The face of the dial is illuminated selectively, when the reading of the dial is desired, by a light-emitting-diode at the center...http://www.google.es/patents/US4688038?utm_source=gb-gplus-sharePatente US4688038 - Remote meter-reader device for gas meters, and the like
Remote meter-reader device for gas meters, and the like
