Fluid dispenser having infrared user sensor

(54) Title: HANDS-FREE DISTRIBUTOR TO DISTRIBUTE A PRODUCT IN A TARGET AREA, AND, METHOD TO DISTRIBUTE PRODUCT (30) Unionist Priority: 06/27/2007 us 11/823248 (73) Holder (s): Joseph S. Kanfer (72) Inventor (s): Chip W. Curtis, Jackson W. Wegelin (57) Summary: hands-free distributor to DISTRIBUTE A PRODUCT IN A TARGET AREA, AND, METHOD FOR DISTRIBUTING PRODUCT. A distribution system is presented that uses a controller together with a photodetector in order to provide automatic distribution to a user when an object enters a target area. A controller is programmed to pulse a light source that is mounted close to the photodetector. The controller constantly monitors the voltage when receiving a signal from the photodetector, and evaluates the difference in the voltage of the pulsed light on / off. The controller adds up the differences, and constantly updates the differences over a given period to create an average difference value. The average difference value is added to a Target Compensation Value and compared to a momentary voltage difference. When the momentary difference exceeds the sum of the Target Compensation Value and the average difference, the controller sends a signal to a distribution mechanism that distributes a fluid or other product over an object.

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ΡΙ0804745 -6 “HANDS-FREE DISTRIBUTOR TO DISTRIBUTE A PRODUCT IN A TARGET AREA AND METHOD TO DISTRIBUTE PRODUCT”

TECHNICAL FIELD

The invention relates to fluid dispensers and methods for dispensing fluid. More particularly, the invention relates to hands-free, electric fluid dispensers, and methods for delivering liquid fluid when an object enters a target field. BACKGROUND OF THE INVENTION

Automatic dispensing devices that provide liquids, towels, or other materials are known in the prior art. It is also well known that devices for automatically distributing fluid or the like to a user's hands, without requiring manual operation or any physical contact on the part of the user, are known in the prior art. It is well known in the art that such a distributor can employ an electronic control circuit that monitors a voltage generated by a photo-sensor to detect the presence of a user. The first hands-free devices employed a light-emitting diode (LED) in communication with a photodiode. When a user was within the target, the photodiode voltage changed and a signal was sent to supply power to a distributor motor. However, distributors using this technology fail to compensate for changes in environmental lighting conditions. In addition, these distributors have energy demand problems, because the detection circuits require constant energization.

A known hands-free dispenser is shown in US patent 5,772,291, Byrd et al .. The hands-free device in Byrd's patent includes both an array of photovoltaic cells and a photo sensor, which detect the amount of light present in the room. The array of photovoltaic cells supplies a referential voltage to the negative input, and photo2 /

! sensor supplies a detection voltage to the positive input. This allows the distributor motor to be activated when the voltage of the photo sensor becomes higher than the reference voltage of the ambient light. Since the array of photovoltaic cells supplies power to the control circuit, the distributor will work only if there is a light present in the room. The device in the patent by Byrd et al. requires two separate detection devices that require additional hardware.

Distributors that measure capacitance as a means of detection are also well known in the art. Conductors are arranged in the unit to provide a capacitance value. One of this device is shown in US patent 6,903,660, Hansen et al. This hands-free device comprises a differential frequency discriminator, used in a signal detection circuit, first and second measuring circuits and a comparator. When the change in average capacitance is greater than that allowed by adjusted parameters, the motor is energized and a fluid is distributed.

Another common “hands-free” distributor, known in the art, uses pulsed signals similar to those applied to a television set. One such distributor is found in the US patent

4,786,005, Hoffman et al. This distributor contains circuits, where a phototransistor detects a drop in the ambient light level. When the phototransistor detects a drop in the ambient light level, the input of the photo-transistor integrated circuit decreases. The voltage of the photo-transistor is modulated and channeled, through a transistor, to energize an LED in a pulsed infrared light, distinct from any parasitic infrared light that may be received by an infrared sensor receiver. The distributor uses a different photo-transistor to detect the pulsed light signal and then communicates with the circuit that energizes the distributor's motor. Detection of parasitic infrared light can cause unwanted distribution events.

In light of the above, it is desirable to provide an improved electronic control system for use in an automatic fluid dispenser of the type generically described above, which presents low average energy consumption, while providing significant immunity to background noise.

SUMMARY OF THE INVENTION

It will be appreciated from the above that there is a primary need for an inexpensive handsfree distributor system that operates with low energy consumption and takes into account changes in lighting conditions.

Consequently, it is an aspect of the present invention, to provide an improved electronic control circuit for use in controlling an automatic fluid distributor.

It is another aspect of the present invention to employ a controller to interpret the voltages supplied by a photodiode to control the hands-free operation of a distribution unit.

It is an additional aspect of the present invention to prevent continuous distribution if the user or object remains in a targeted area.

It is yet another aspect of the present invention to constantly adapt to environmental light conditions, adjusting parameters for the functioning of the distributor.

It is yet another aspect of the present invention to monitor an average difference in light conditions from recent ambient conditions and compare momentary differences in light conditions to detect an object.

It is an additional aspect of the present invention, to distribute fluid when a sudden change in the difference in light conditions exceeds the sum of an average difference in lighting conditions and a compensation value.

The exemplary system presented here fulfills these requirements, providing a hands-free dispensing device that operates with low energy consumption. The dispensing device uses an infrared light emitting diode (IR LED), a photodiode and a controller that takes into account the presence of a user and communicates the received signal to a distribution mechanism to supply fluid to a user. This dispensing device can be permanently attached to the dispenser, or can be incorporated into a replacement cartridge carried by the dispenser. This invention relates, in general, to the field of fluid dispensers, and it should be understood that the following hands-free control circuits could easily be adapted to devices that distribute paper towels or other materials. One embodiment will be described as a soap dispenser, but it should be readily apparent that the present invention can also be applied to a variety of dispensers that can deliver other fluids or paper products.

Another aspect of the present invention is to provide a hands-free distributor to distribute a product in a targeted area, comprising a distribution mechanism, a light emitting diode associated with the distribution mechanism, a controller, and a photodetector associated with the emitting diode. light that detects light levels in a target area and generates a voltage received by the controller that corresponds to the detected light levels, when the controller compares a Momentary Difference Value in voltage to an Average Difference value in voltage plus a target Compensation value, the controller sending a signal to the distribution mechanism when the Momentary Difference Value is greater than the Average Difference Value plus the Target Compensation Amount.

! Yet another aspect of the present invention is to provide a method for distributing the product, comprising pulsating a light source close to

I a photodetector, read and store an Active Voltage value from the photodetector ¹ when the light source is illuminated, read and store a value of

Ambient Voltage of the photodetector when the light source is not illuminated, calculate a Momentary Difference between the Active Voltage value and the Ambient Voltage value, compare the Momentary Difference to a sum of an Average Difference and a Target Compensation, from It hurts

l ^! that the Average Difference is calculated from previous values ​​of Differences

Momentary of the photodetector over a time interval, generating a distribution signal when the Momentary Difference is greater than the sum, and distributing the product when the distribution signal is received by a distribution mechanism.

These and other aspects of the present invention, as well as their advantages over forms in use of the prior art, will become readily apparent from the description below, being achieved by implementing the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a complete understanding of the objectives, techniques and structure of the invention, reference should be made to the following detailed description and accompanying drawings, in which:

Fig. 1 is a schematic diagram of a hands-free dispenser made in accordance with the concepts of the present invention;

Fig. 2 is a detailed schematic diagram of the distributor 25 showing a controller, an infrared LED, and a photodiode according to the present invention;

FIG. 3 is a circuit diagram of a control circuit used by the distributor in accordance with the concepts of the present invention; and

FIGS. 4A and 4B show a flow chart of the steps /

to distribute the product.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings and, more particularly, to the

Fig. 1, it can be seen that the distributor made according to to the invention is generally designated by the numeral 10. The distributor 10 includes a housing structure of the distributor, of widely known distributors, generally designated by the numeral 12. The distributor housing 12 can be an opposing wall or unit, or it can be a stand-alone unit arranged on a counter top or the like. The dispenser described here is used to distribute fluids, such as soaps and other liquids, but it will be appreciated that other products could be distributed, such as paper, tablets, or any flowable material. In any case, the housing of the dispenser 12 typically includes a liquid product cartridge 14 positioned above, and, in communication with a dispensing nozzle 16, with a suitable pump or other dispensing mechanism 18 interposed between them. As is well known to those skilled in the art, delivery mechanism 18 is configured to deliver a pre-set amount of liquid to each delivery cycle. According to the invention, the delivery mechanism 18 is controlled by a drive mechanism 20, such as a motor, solenoid, plunger or the like. The mechanism 20 is energized with the detection of an object, such as a user's hands, positioned under the dispensing nozzle 16.

Referring now to Fig. 2, it can be seen that a control circuit, generally designated by numeral 21, is connected to the drive mechanism 20. Control circuit 21 includes an appropriate photodetector 22, which is positioned in association with, and / or, in the vicinity of the nozzle 16, and which detects the presence of hands or other object in the target area by means of an appropriate reflected signal, or the like. Therefore, detector 22 can actually be a transducer, both sending and receiving signals. The invention presented and described in detail below is an improvement and refinement of the distributor 10.

In the present embodiment, photodetector 22 comprises a photodiode 23 that detects ambient light and infrared light emitting diode (IR LED) light 24. In this way, photodiode 23 detects a wide range of light wavelengths within a predetermined distance from it. For proper operation of the distributor, photodiode 23 is used to determine an ambient light value. The person skilled in the art will appreciate that the value of ambient light varies depending on the distributor being kept in a room with windows and the amount of daylight in the room, the type of artificial lighting in the room and the level of reflectivity of the surfaces in the vicinity of the distributor. . As will be explained in more detail, photodiode 23 also detects reflected light from an object that is positioned relatively close to it and which is generally attributable to the light generated by LED 24. In this way, infrared light reflected by any object that is detectable by the photodiode 23 enables the drive mechanism 20, resulting in the distribution of a predetermined amount of material. The control circuit 21 additionally includes a controller 26 that receives data or an appropriate signal from the photodiode 23. In operation, the device is normally in a ready condition, waiting for the detection of an object by the photodiode 23. In some embodiments, the photodetector can also be a photo-transistor, etc.

In Figs. 2-3 it can be seen that the IR LED 24 is controlled by the controller 26 to produce short pulses at a significantly higher current compared to the prior art. For example, IR LED 24 can pulse for less than 150 microseconds and operate between 100 mA at 1.5 A. In other embodiments, IR LED 24 'can pulse for a period of approximately 10 microseconds and operate between 0.5 A and 1 A. IR LED 24 is mounted close to photodiode 23. Controller 26 monitors the amount of voltage on photodiode 23. Photodiode 23 can be positioned anywhere on distributor 10, or mounted separately, as long as photodiode 23 can detect reflected light emitted by IR LED 24. Controller 26 of some At the same time, it generates a signal to energize the IR LED 24 and reads the voltages produced by the photodiode 23. These voltage values ​​- referred to as 'active' - are then compared to recently read voltage values ​​and classified as being representative of ambient light values. These values ​​are then processed by the controller in the manner that will be described.

An external power source 25 is supplied to photodiode 23 separate from controller 26. Consequently, a photodiode amplifier can be incorporated within distributor 10 to provide an amplified signal required by controller 26 to detect the amount of light from the surrounding environment to distributor 10 Amplification of the photodiode can be achieved in a variety of different media. In one embodiment, reverse bias circuits are used to achieve sufficient amplification.

Controller 26 provides the hardware, software and memory necessary to implement the control circuit functions and correctly operate distributor 10. Controller 20 could be a microcontroller, such as the one manufactured by Zilog. Of course, controllers manufactured by others could be used. Controller 26 may also include, among other components, multiple oscillators 26A and an analog-to-digital converter 26B. Generally, one of the multiple oscillators 26A could be an internal oscillator which, if properly connected, can run continuously. Other oscillators can be used for other functions. Those skilled in the art will appreciate that controller 26 includes a protection timer associated with the internal oscillator, so that the controller can be stopped or paused for a predetermined period of time.

Consequently, the complete operation of the controller only occurs in predetermined increments, to reduce the current consumption of a power source. This saves energy and helps to extend the life of the power source, which can be in the form of a battery. The converter 26B is used by the controller to receive the analog signals of the voltage generated by the photodiode 23 and to convert the signals into digital values, in order to allow further processing and the operation of the distributor. The converter 26B can be in the form of a comparator or an Analog-Digital Converter of Successive Approach Record.

Controller 26 generates and sends a signal to the drive mechanism 20 when an object is detected within the target field. The instructions of the program maintained by controller 26 use the following variables, which will be defined for the purposes of the present invention: Active Voltage, Ambient Voltage, Momentary Difference, Average Difference, Target Level Compensation, and Distribution End signal. Active Voltage refers to the voltage value that controller 26 monitors and records from photodiode 23 when IR LED 24 is on. Voltage of

Environment refers to the voltage value that controller 26 monitors and records from photodiode 23 when IR LED 24 is off. The Momentary Difference is calculated by controller 26 and is equal to the difference between the Ambient Voltage and the Active Voltage. The controller programming logic discards negative Momentary Difference values. This is done so that the controller disregards values ​​that are usually generated by a sudden change in the light conditions of a room. The Average Difference is a calculated value that is based on a series of Active Voltage minus differences from the Ambient Voltage. An initial Mean Difference value is set to a large, arbitrary value in the controller programming. In the present embodiment, the initial value for the average difference is 0.7 volts. Of course, other voltage values ​​could be used as appropriate. Subsequent Mean Difference Values ​​are equal to the average of the Active Voltage minus the Voltage of the

Environment registered on a mediating cycle. The mediating cycle can take any number of readings taken over a period of time. In one embodiment, the mediating cycle consists of four readings per second, for eight seconds (32 readings). Mean Difference ignores negative values ​​and measured values ​​when an object is detected, as well as any negative readings of the voltage value.

To start a distribution cycle, controller 26 requires that the Momentary Difference exceed the Average Difference plus a Target Level Compensation. The Target Level Compensation variable acts as a threshold so that controller 26 only generates a signal to activate the drive mechanism 20 when an object is in the detection range of photodiode 23. A fixed 50 mv Target Level Compensation is a exemplary value. The Target Level Compensation can also be calculated based on a percentage compared to the voltage levels provided by photodiode 23 or a combination of a fixed value according to an average value calculated based on previous experience. A Distribution End signal is the output produced by a microswitch 27 or similar, which indicates the end of a distribution cycle. In one embodiment, the microswitch 27 is associated with the drive mechanism 20. For example, the microswitch 25 could be positioned on the gears of a pump, so that microswitch 27 is activated on a complete turn of a pump cam shaft. Receiving the Distribution Termination Signal 27 would cause the controller to stop the drive mechanism 20.

Controller 26 compares the Momentary Difference to

Mean Difference plus Target Level Compensation to determine whether to send a signal to the drive mechanism. Controller 26 dispatches a signal to the drive mechanism 20 when the Momentary Difference value exceeds the sum of the Average Difference plus Compensation of

Target Level. The controller only searches for a target about every 0.25 seconds, or another predetermined period of time. When not looking for the target, the controller is operating only minimal functions in order to consume only the minimum amount of energy needed to maintain its operation. Controller 26 includes this low duty cycle in order to keep energy consumption low. The speed at which the distribution unit is directly related to the speed at which the logic variables are obtained and the speed at which the controller 26 processes the information. In one embodiment, controller 26 operates at approximately 5.5 MHz when searching for a target.

The operational process performed by the controller for object detection is designated by numeral 28, as shown in Figs. 4A and 4B of the drawings. Detection of object 28 has an initialization sequence in step 30. In step 32, controller 26 measures the voltage of photodiode 23 when IR LED 24 is off and stores the value as the environment. In step 34, controller 26 then measures the voltage of photodiode 23 when IR LED 24 is on, and stores the value as active. Controller 26 assumes that no object is within the target range when measuring the values ​​for steps 32 and 34. Controller 26 then calculates the Momentary Difference by calculating the difference between the active and ambient values ​​as shown in step 36. If the Momentary Difference is positive, then a decision is made as shown in decision block 38. When the Momentary Difference is determined to be negative as shown in step 40, the value is discarded and the logic starts a new sequence resuming to step 32. When the Momentary Difference is positive as shown in block 42, the logic compares the Momentary Difference to the sum Average Difference and a Target Compensation Amount. When the Momentary Difference is less than the sum as represented in step 44, the value is added to the value of the Mean difference and the logic starts a new sequence starting back at step 32.

When the Momentary Difference is greater than the sum as shown in step 46, controller 26 sends a signal to the drive mechanism. As shown in step 48, the controller waits for the Distribution End Signal 27 to determine whether the distribution mechanism is currently in operation. If the Distribution End 27 signal is detected in step 48, the controller stops the motor as shown in block 32. If the Distribution End 27 signal is not detected in step 48, the controller determines whether a predetermined period of time such as three seconds has elapsed since the start of the distribution cycle as shown in step 50. If the elapsed time is less than the predetermined period of time, logic returns to block 46. However, if the elapsed time is longer than the predetermined time period, the drive mechanism for the distribution cycle as shown in step 52. The maximum amount of time for execution can be any value.

The controller calculates another Momentary Difference value designated as Momentary Difference 'as shown in steps 54, 66, and 58. The Momentary Difference' shown in step 58 is somewhat similar to the Momentary Difference calculation represented in steps 32-36. Note that in step 54 a timer is started for a period of time, such as ten seconds. This timer is used to ensure that the previously detected object is moved. Thus, the following steps prevent the distributor from distributing material continuously in case someone places an object on the LED strip, but does not remove the object. In any case, a determination is then made as if the Momentary Difference 'is positive as shown in step 60. When the Momentary Difference' is negative, then in step 62 the value is discarded and the controller logic starts a new sequence that starts back to step 32. However, when the Momentary Difference 'is positive, then, in step 64 the logic compares the

Momentary Difference 'to the sum of the Average Difference plus a Target Compensation Value. When the Momentary Difference 'is less than the sum calculated in step 64, the calculated Momentary Difference' value is incorporated into the Average Difference value in step 66 and the logic starts a new sequence that starts back to step 32.

When the Momentary Difference 'value is greater than or equal to the sum calculated in step 64, controller 26, in step 68, then excludes the Momentary Difference' value from the next Average Difference calculation. This is done so that the Average Difference value is not distorted. In step 69 a determination is made as to whether the time started in step 54 has elapsed or not. If the time has not elapsed, the process proceeds to step 56. If the time has elapsed, then the process returns to step 30. Using the timer, if a certain time is reached and the target has not left, the controller will recalibrate to restore the Mean Difference value. Controller 26 may include means for converting an analog signal to digital at a speed below 20 microseconds that can be achieved by using converter 26B.

As noted previously, controller 26 is stopped or paused when not looking for a target, and operates between 1 MHz and 20 MHz when looking for a target. In one embodiment, controller 26 uses an internal oscillator that operates around 5.5 MHz when looking for a target. Controller 26 may also use a low frequency oscillator when the controller is paused or stopped, so that other oscillators and other functions of the controller are activated at the appropriate time. The low frequency oscillator can operate between 5 kHz and 200 kHz. In one embodiment, the internal low-frequency oscillator operates at approximately 10 kHz.

Although the described embodiments suggest values ​​of the operation, it should be appreciated that someone skilled in the art could easily apply comparable values, while remaining within the spirit of this invention.

Thus, it can be seen that the objectives of the invention were satisfied, by the structure and by its method, for the use presented above. Although according to the Patent Statutes, only the best and preferred embodiments have been presented and described in detail, it should be understood that the invention is not limited to them or by them. Consequently, for an appreciation of the true scope and scope of the invention, reference should be made to the following claims.