System and method for filtering reflected infrared signals
A system for preventing IR reflection ghosting in a fluid-dispensing device having a transmitter/receiver pair and control logic. The control logic interfaces with the transmitter and the receiver, activating the fluid-dispensing device when an object is present within the transmitter detection range by comparing a set predefined value with the IR value obtained. When the reflection is above the detection level, the control logic further evaluates two consecutive pulses to detect movement between said two consecutive pulses. An increase in IR value indicates movement, thereby causing the fluid-dispensing device to be activated.
1 . A system for processing reflected infrared signals which are used to control the flow of water from a water faucet or the like, said system comprising:
an IR transmitting device for transmitting an IR signal toward a location proximate the place from which water may be dispensed from the faucet;
an IR receiving device for receiving a reflected IR signal from a detection range proximate the location from which water may be dispensed from the faucet, said IR receiving device providing an output signal, said output; signal being proportional to the magnitude of the reflected IR signal; and
control logic configured to receive said output signal from said IR receiving device, wherein said control logic compares said output signal with an activation threshold to determine the presence of an object within said detection range, said control logic further configured to detect the occurrence of motion within said detection range, said control logic providing a water control signal which may be used to control the flow of water through the faucet based upon the results of the determination of the presence of an object within the detection range and the occurrence of motion within said detection range.
2 . A system defined in claim 1 , said system further comprising a fluid dispensing device, water control valve wherein said control logic is configured to activate the water control valve when either the presence of an object within the detection range is determined or the occurrence of motion within said detection range is determined.
3 . A system as defined in claim 2 , wherein said control logic is further configured to execute a timer for a predetermined time interval when said water control valve is activated, and to deactivate said water control valve when timer expires or when the presence of an object within the detection range is no longer determined.
4 . A system as defined in claim 3 , wherein said control logic is configured to detect an increase in said output signal from said IR receiving device and activate the water control valve in response thereto.
5 . A system as defined in claim 1 , wherein said IR transmitting device periodically emits IR pulses, and wherein said IR receiving device is positioned to detect reflections of said IR pulses from said IR transmitting device.
6 . A system as defined in claim 1 , wherein said control logic detects motion by calculating the difference between consecutive samples of said output signal from said IR receiving device and comparing said difference to said activation threshold.
7 . A method for processing reflected infrared signals which are used to control the flow of water from a water faucet or the like, said method comprising the steps of:
transmitting an IR signal from an IR transmitting device toward a location proximate the place from which water may be dispensed from the faucet;
receiving a reflected IR signal with an IR receiving device from a detection range proximate the place from which water may be dispensed from the faucet, said IR receiving device providing an output signal which is proportional to the magnitude of the reflected IR signal;
comparing said output signal from said IR receiving device to an activation threshold to determine the presence of an object within said detection range;
detecting the occurrence of motion within said detection range; and
controlling the flow of water through the faucet based upon the results of said comparing and detecting steps.
8 . (canceled)
9 . A method as defined in claim 7 , wherein said controlling step comprises activating the the water control valve when either the presence of an object within the detection range is determined or the occurrence of motion within said detection range is determined.
10 . A method as defined in claim 9 , said method further comprising the steps of:
setting a timer for a predetermined interval upon activation of the water control valve;
detecting the presence or absence of motion during said predetermined interval; and
deactivating the water control valve when said predetermined time interval expires or when the the water control valve when either the presence of an object within the detection range is determined or the occurrence of motion within said detection range is determined.
11 . A method as defined in claim 10 , said method further comprising the steps of:
detecting the presence or absence of an increase in said output signal from said IR receiving device; and
activating the the water control valve in response to an increase in said output signal from said IR receiving device.