(54) ULTRASONIC FAUCET CONTROL(71) We STANDARD TELEPHONESAND CABLES LIMITED, a British Company of 190 Strand, London W.C.2 IOUEngland, do hereby declare the invention, for which we pray that a patent may be granted to us. and the method by which it is to be performed, to be particularly described in and by the following statement:This invention relates to proximity detectors, and in particular to a detector arrangement employing an ultrasonic reflection technique.
According to the invention there is provided an automatic faucet arrangement adapted to provide a supply of water in the presence of a user, the arrangement including a faucet, an electrically operated valve controlling a water supply to the faucet, and an ultrasonic proximity detector comprising an oscillator coupled to a transducer via first gating means, a detector circuit coupled to the transducer via second gating means and gate control means, the first and second gating means being operable selectively via the control means so as to cause the transducer to emit bursts of radiation and to couple the detector to the transducer for a predetermined portion of the period between each transmission, and in which the arrangement is so adapted that, when an echo signal is received by the detector, the valve is opened thereby supplying water to the faucet.
An embodiment of the invention will now be described with reference to Figures 1 and 2 of the drawings accompanying the Provisional Specification and Figure 3 of the accompanying drawing in which:Figure 1 is a schematic diagram of an ultrasonic proximity detector arrangement for automatic operation of a faucet, and Figure 2 shows the waveforms employed in the circuit of Figure 1. and toFigure 3 of the accompanying drawing which shows an automatic faucet arrangement, fitted with the proximity detector ofFigure 1.
Referring to Figures 1 and 2, the proximity detector arrangement includes an oscillator 11 coupled to an electro acoustic transducer 12 via a first gate 13, the transducer being adapted both to generate and receive acoustic signals. A second gate 14 couples the transducer, via an amplifier 15 tuned to the oscillator frequency, to a level or threshold detector circuit 16 and a velocity sensor circuit 17 arranged in parallel with the threshold detector 16. The gates 13 and 14 are operated via a gate generator circuit 18.
The gate generator feeds a stream of pulses F1 (Figure 2) to the first gate 13 so as to couple the oscillator to the transducer for the duration of each pulse causing the transducer to emit corresponding bursts of ultrasonic radiation F2. In the period between each radiation burst, i.e. when gate 13 is closed, gate 14 is opened by an extended pulse F3 during which period the transducer operates in its receive mode. The duration and time position of the extended pulse F3 determines the operating range of the proximity detector arrangement, i.e. an echo pulse can be received only during the receive 'window' defined by the pulse F3.
Echo signals F4 received from an object 19 during the pulse F3 generate a corresponding electrical signal in the transducer, which signal is fed via gate 14 to the tuned amplifier 15. The amplifier output is coupled to the threshold detector 16 which produces an output signal if the amplifier output exceeds a predetermined amplitude.
Such an arrangement defines the range of the detector. By suitable adjustment of the gate generator unwanted echo signals frpm remote objects can thus be prevented.
Referring to Figure 3 of the accompanying drawing, the arrangement of Figure 1 is shown coupled to a faucet arrangement so as to provide automatic hands-free operation, such as is required in a hospital operating theatre. The faucet 31 is provided with a solenoid valve 32 operable via a servo-amplifier 33. The gate generator circuit 18 (Figure 1) is so arranged that the receive signal 'window' corresponds to a predetermined maximum distance, e.g. 2 metres, between the faucet and a user.
When the user approaches closer than this distance reflected ultrasonic signals are received by the detector thus producing an output and causing the servo-amplifier 33 to open the solenoid valve 32. Similarly, when the user recedes from the faucet beyond the predetermined distance, the reflected signal is no longer received and the solenoid valve shuts off.
WHAT WE CLAIM IS:1. An automatic faucet arrangement adapted to provide a supply of water in the presence of a user, the arrangement including a faucet, an electrically operated valve controlling a water supply to the faucet, and an ultrasonic proximity detector comprising an oscillator coupled to an ultrasonic transducer via first gating means, a detector circuit coupled to the transducer via second gating means and gate control means, the first and second gating means being operable selectively via the control means so as to cause the transducer to emit bursts of ultrasonic radiation and to couple the detector to the transducer for a predetermined portion of the period between each transmission and in which the arrangement is so adapted that, when an echo signal is received by the detector, the valve is opened thereby supplying water to the faucet.
2. An automatic faucet substantially as described herein with reference to Figure 3 of the accompanying drawing together withFigures 1 and 2 of the drawing accompanying the Provisional Specification.
3. A method of controlling an automatic faucet substantially as described herein with reference to the drawings accompanying theProvisional Specification and to the accompanying drawing.
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