Patent GB-1101420-A (GB)
Title: Voice-controlled actuator
Inventor: SHER IRVING HAROLD
IPC: G07C9/00
Filed: 1964-12-22
Abstract: 1,101,420. Controlling and actuating by sound. INSTITUTE FOR SCIENTIFIC INFORMATION. 22 Dec., 1964, No. 52088/64. Heading G4F. [Also in Division E1]  A voice-controlled actuator comprises a first sensing system 22 including an audio spectral analysing device 30 coded to yield an output signal in response to a signal including specific spectrum of audio frequencies by comparison of a received signal with a record of the audio spectral characteristics of a specific command signal in the form of sound uttered by a specific individual; a second and similar sensing system 23 coded to respond to any received signal other than the said command signal to inhibit an output signal from the device of said first sensing system; and means for applying a received voice signal to the sensing systems. In the construction shown, the transducer is a microphone 24 and this is connected to an electromechanical driver 58 of the analyzing device. The analyzing device comprises in addition, a fibre optic array 60 which comprises a large number of tiny quartz fibres 64, all held at one end by an inclined or otherwise contoured base 62 so that all the fibres 64 are of different lengths so that, since each is a tiny cantilever beam, each will vibrate at a different frequency whenever it is mechanically excited at its natural frequency. Each fibre has sufficient space around it to vibrate in any direction without striking any other fibre. The analyzer also includes an incandescent lamp 36 and a diffuser 54 which are placed in a light sealed housing 56 on top of the electromechanical driver 58 so that the light from the lamp can pass through the fibre optic array 60. The electromechanical driver 58 shakes the fibre optic array in response to an audio signal received by the microphone and to sense the pattern of fibre motion, a mask is imposed between the fibre optic array and a photo-cell 66. The mask 52 is made by placing a photographic plate between the fibre optic array and the photo-cell and vibration of the array by a specific audio signal will cause each fibre that vibrates to leave a black line on the negative developed from the photographic plate and each which does not vibrate to leave a black spot; elsewhere the plate will be transparent. A positive is produced from the negative and this is used as the mask in conjunction with a negative formed by placing a photographic plate between the mask and the photo-cell and illuminating the array when the array is not vibrated; this produces an array of small spots on the photographic plate when developed, corresponding to the number of fibres. A mask produced from the positive and negative formed in this way will only pass light from the fibres which move in response to the specific audio signal used in producing the positive plate and this falls on the photo-cell and is used to actuate a time delay relay 74 via a Zener diode which only allows the relay to operate when the intensity of light on the photo-cell exceeds a specific amount. The contacts 46 of the relay complete the circuit to a control device 42 for a servomotor which, as described, withdraws a latch bolt to unfasten a door. To prevent a blast of sound which contains the frequencies of the specific audio signal operating the control device 42 the second sensing system is connected in parallel with the first to the microphone and in this system the negative photographic plate produced by the specific audio signal is used as the mask between the fibre optic array 60 and the photo-cell. This sensing system responds to all frequencies other than those of the specific audio signal and the relay controlled by the photo-cell opens a contact in the circuit of the control device 42 when such additional frequencies are present in the signal received by the microphone. When the mechanism is used as a lock mechanism for a door to withdraw a bolt, a switch is provided in a knob on the door which must be pressed to provide power to the mechanism. If it is desired that two separate command signals can operate the servomotor, two additional sensing systems as above are provided connected to a common microphone and controlling the servomotor, the relay contacts being arranged in parallel with those of the first pair of sensing systems. An arrangement is also described by which two separate command signals are required to operate the servomotor.