Abstract:
A home soda machine includes a cylinder of gas suitable for carbonation, an attachment mechanism to attach a bottle of water, a valve opening mechanism to open a gas release valve on the gas cylinder and introduce the gas to the bottle of water, a gas release sensor to sense at least events indicating the opening and closing of the gas release valve, and an indirect gas meter to at least determine an amount of the gas released from the cylinder based at least on a cumulative length of time the gas release valve was open as per data received from the gas release sensor.

Description:
FIELD OF THE INVENTION 
     The present invention relates to home soda machines generally and to gas metering for such machines in particular. 
     BACKGROUND OF THE INVENTION 
     Home soda machines for the carbonation of beverages are known in the art.  FIG. 1 , to which reference is now made, illustrates a simplified view of a typical such home soda machine  100 . Home soda machine  100  may comprise a gas release lever  10 , a bottle attachment mechanism  20 , a pressurized cylinder  30 , release valve  40  and water bottle  50 . 
     Gas release lever  10  controls the state of release valve  40 . When lever  10  is pressed in the direction of arrow  15 , release valve  40  opens to enable the flow of gas from cylinder  30  via gas tube  45  to mechanism  20 . Releasing lever  10  returns it to its previous position and valve  40  closes. 
     Water bottle  50  is typically filled with water and affixed to mechanism  20 . When gas release lever  10  is pressed down against release valve  40  CO 2  gas from pressurized cylinder  30  is introduced into the water in water bottle  50  through bottle attachment mechanism  20 . This procedure is typically repeated until a desired level of carbonation is reached. When soda preparation is finished, bottle attachment mechanism  20  is tilted to allow pressure to be released and to enable bottle  50  to be detached. 
     Such soda machines  100  are not typically equipped with means to inform a user regarding the amount of CO 2  remaining in cylinder  30 . Adding a gas meter capable of accurately measuring the levels inside cylinder  30  would significantly increase the cost and complexity of machines  100 . Accordingly, users of machines  100  typically have no advance warning before cylinders  30  run out of CO 2 . 
     SUMMARY OF THE INVENTION 
     There is provided, in accordance with an embodiment of the invention, a home soda machine including a cylinder of gas suitable for carbonation, an attachment mechanism to attach a bottle of water, a valve opening mechanism to open a gas release valve on the gas cylinder and introduce the gas to the bottle of water, a gas release sensor to sense at least events indicating the opening and closing of the gas release valve, and an indirect gas meter to at least determine an amount of the gas released from the cylinder based at least on a cumulative length of time the gas release valve was open as per data received from the gas release sensor. 
     Further, in accordance with an embodiment of the invention, the home soda machine also includes a tilt sensor to sense at least events indicating replacement of the bottle of water. 
     Still further, in accordance with an embodiment of the invention, the tilt sensor is at least one of an SPST-type mechanical switch, a reed switch sensing a presence/absence of a magnet attached to another element of the home soda machine, and a slotted optical sensor. 
     Additionally, in accordance with an embodiment of the invention, the gas release sensor is at least one of an SPST-type mechanical switch, a reed switch sensing a presence/absence of a magnet attached to another element of the home soda machine, a slotted optical sensor, a microphone to detect sounds of gas moving through the gas release valve, an integrated gas flow meter, and a pressure sensor. 
     Moreover, in accordance with an embodiment of the invention, the home soda machine also includes a cylinder sensor to sense at least events indicating replacement of the cylinder of gas, where the cylinder sensor is at least one of a mechanical switch, a capacitive sensor, an inductive proximity sensor, and a reflective optical sensor. 
     Further, in accordance with an embodiment of the invention, the cylinder of gas contains CO 2 . 
     Still further, in accordance with an embodiment of the invention, the indirect gas meter includes a pushbutton to facilitate user input, where the pushbutton. 
     Additionally, in accordance with an embodiment of the invention, the indirect gas meter includes a central processing unit to calculate the amount of gas released based on at least the cumulative length of time and expected release rates for the cylinder of gas. 
     Moreover, in accordance with an embodiment of the invention, the indirect gas meter also includes means to estimate a level of carbonation in the water bottle based on at least the cumulative length of time and expected release rates for the cylinder of gas. 
     Further, in accordance with an embodiment of the invention, the indirect gas meter includes a timer to facilitate calculating the cumulative length of time. 
     Still further, in accordance with an embodiment of the invention, the indirect gas meter includes at least one of an audio unit and a display unit to provide feedback to a user, where the audio unit is at least one of a speaker or piezoelectric buzzer. 
     Additionally, in accordance with an embodiment of the invention, the feedback includes at least one of warnings to replace the cylinder of gas, and an indication of a level of carbonation in the water bottle. 
     Moreover, in accordance with an embodiment of the invention, the indirect gas meter includes a weighted average calculator to calculate predicted lengths of time required to empty the cylinder of gas based on a weighted average of actual the lengths of time observed for previously used the cylinders of gas. 
     Further, in accordance with an embodiment of the invention, the weighted average calculator includes means for storing at least a history of actual usage times for the cylinder of gas, where each of the actual usage times represent a cumulative time the cylinder of gas was activated to release gas before being replaced. 
     Still further, in accordance with an embodiment of the invention, the means for storing are configurable to store multiple instances of the at least a history to represent the actual usage times for a multiplicity of different sized the cylinders of gas. 
     There is also provided, in accordance with an embodiment of the invention, a method implemented on a home soda machine to indirectly meter contents of a cylinder of gas, the method including receiving indications that a gas release valve associated with the cylinder of gas is opening and closing, timing intervals between each the opening and associated closing, computing a total cumulative time between the intervals, and comparing the total cumulative time with an expected usage time for the cylinder of gas to calculate a remaining amount of gas in the cylinder of gas. 
     Further, in accordance with an embodiment of the invention, the method also includes alerting a user regarding an anticipated need to replace the cylinder of gas when the remaining amount is below a threshold level. 
     Still further, in accordance with an embodiment of the invention, the alerting is performed via at least one of an audio unit and a display unit. 
     Additionally, in accordance with an embodiment of the invention, the expected usage time is calculated as a weighted average of a series of recently computed the total cumulative times for other cylinders of gas. 
     Moreover, in accordance with an embodiment of the invention, the method also includes storing separate histories of the total cumulative times for different sizes of the cylinders of gas. 
     Further, in accordance with an embodiment of the invention, the method also includes configuring a pushbutton to indicate a change in size when replacing the cylinder of gas. 
     Still further, in accordance with an embodiment of the invention, the method also includes sensing replacement of a water bottle attached to the home soda machine, where contents of the water bottle are carbonated by gas released from the cylinder of gas. 
     Additionally, in accordance with an embodiment of the invention, the method also includes calculating a total cumulative time between the intervals for a current the water bottle, and estimating a level of carbonation for the current water bottle based on the calculating. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which: 
         FIG. 1  is a schematic illustration of a prior art home soda machine; and 
         FIG. 2  is a schematic illustration of a novel home soda machine with an indirect gas meter, constructed and operative in accordance with an embodiment of the invention. 
     
    
    
     It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the invention. 
     Applicants have realized that typical users of home soda machines  100  may not require the level of accuracy provided by prior art gas metering mechanisms. Instead, indirect methods of measuring the gas inside of cylinders  30  may be employed to significantly reduce the cost while still providing generally accurate measurements to a user. 
       FIG. 2 , to which reference is now made, illustrates a novel indirectly metered home soda machine  200  constructed and operative in accordance with an embodiment of the invention. Home soda machine  200  may comprise generally the same elements as in the prior art. Machine  200  may also comprise an indirect metering device  155  which may receive input from tilt sensor  160  and lever sensor  165  via wires  161  and  166  respectively. 
     Tilt sensor  160  may be a sensing device that may be installed in such a manner as to sense the tilting of the bottle attachment mechanism  20 . It will be appreciated that inserting or releasing water bottle  50  may require that mechanism  20  be tilted, such that tilt sensor  160  may provide an accurate indication of a replacement of water bottle  50 . Sensor  160  may be any suitable device, such as, for example, a simple SPST-type mechanical switch, a reed switch sensing the presence or absence of a magnet attached to another element of machine  200 , or a slotted optical sensor. 
     Lever sensor  165  may be a similar device that may be positioned to detect downward movement of gas release lever  10 . It will be appreciated that in such manner sensor  165  may provide an accurate indication of when gas may be released from cylinder  30 . As with sensor  160 , Sensor  165  may be any suitable device, such as, for example, a simple SPST-type mechanical switch, a reed switch sensing the presence or absence of a magnet attached to another element of machine  200 , or a slotted optical sensor. 
     Indirect metering device  155  may comprise a central processor unit  170 , a pushbutton  175 , an audio unit  180 , a battery  185 , and a display unit  190 . Central processor unit  170  may be any suitable device, such as a microprocessor, capable of processing the instructions necessary for the implementation of the invention. It may receive information from sensors  160  and  165  via wires  161  and  166  regarding user actions such as, for example, activation of gas release lever  10  and the insertion/removal of water bottle  50 . 
     Central processor unit  170  may also comprise a timer unit  171  that may comprise clock functionality required for the calculation of elapsed time. As unit  170  may receive indications from sensor  165 , timer unit  171  may calculate the accumulated time that lever  10  may have been engaged, thereby providing an indication regarding the cumulative amount of CO 2  gas that may have already been released from cylinder  30 . It will be appreciated that the amount of CO 2  gas in a new, pre-filled cylinder  30  may be known in advance, as well as the typical flow rate of CO 2  gas through to bottle  50 . Thus, the remaining quantity of CO 2  gas in cylinder  30  may be calculated with a relatively high degree of accuracy. Similarly, the amount of CO 2  introduced into a current water bottle  50  since it was inserted into machine  200  (as indicated by a signal from sensor  160 ) may also be calculated with a relatively high degree of accuracy. 
     It will be appreciated that these two calculations may provide information of benefit to the user of machine  200 . Calculating the remaining CO 2  gas in cylinder  30  may enable the user to procure a replacement before the current cylinder  30  totally empties. And by measuring the flow of CO 2  gas into water bottle  50 , it may be possible to provide a representation of the level of carbonation in the current water bottle  50 . 
     This information may be conveyed to the user using display unit  190 , in a graphical and/or textual manner, such that various levels such as ‘low’, ‘medium’, and ‘high’ may be used to indicate the CO 2  level in cylinder  30  and/or the level of carbonation in water bottle  30 . In accordance with an embodiment of the invention, other visual displays may be presented on display unit  190 , such as, for example, an indication of the carbonation level of the currently prepared bottle  50 , both while it is being prepared and afterwards; a visual representation of the level of CO 2  gas remaining in cylinder  30 , which may also include a specific ‘cylinder near empty’ indication triggered by a specific pre-determined low threshold; and/or a visual indication of the amount of CO 2  emissions saved, which may be derived by calculating the difference between the carbon footprint of the total amount of soda bottles prepared by the particular soda machine (as counted by processor unit  170 ) and the pre-calculated total carbon footprint of an identical number of soda bottles purchased as a pre-bottled, commercial soft drink (off the shelf). 
     In accordance with an alternative embodiment of the invention, audio unit  180  may be used in conjunction with, instead of, or in addition to, unit  190  as a means for conveying such information to the user. Audio unit  180  may be any suitable means for providing audio signals to a user, such as, for example, a speaker or piezoelectric buzzer. Accordingly, for example, unit  170  may instruct audio unit  180  to emit an audible alarm when the CO 2  level in cylinder  30  may be determined to be lower than a defined threshold. 
     In accordance with another embodiment of the invention, device  155  may be configured to check for the need to emit audible alarms when triggered by specific events. For example, when the removal or the insertion of a water bottle is sensed by sensor  160 , processor unit  170  may check the CO 2  level in cylinder  30  and instruct audio unit  180  to emit an audible alarm if the level is below the warning threshold. 
     In accordance with another embodiment of the invention, device  155  may be configured to use different audible alarms to indicate different states. For example, when enough CO 2  remains in cylinder  30  to carbonate two water bottles  50 , audio unit  180  may emit three audio alarms in rapid succession. When there may only be enough CO 2  to carbonate one water bottle  50 , audio unit  180  may emit two alarms in rapid succession. When there may be no CO 2  left in cylinder  30 , audio unit  180  may emit one long alarm. It will be appreciated that this is just one possible configuration; the invention may include any suitable configuration. 
     In order to calculate CO 2  levels for a current cylinder  30 , indirect metering device  155  may require input as to when cylinder  30  may have been most recently replaced. In accordance with an embodiment of the invention, the user may use pushbutton  175  as per instructions that may be displayed on display unit  190  to “manually” indicate when cylinder  30  may have been replaced. In accordance with an alternative embodiment of the invention, an optional cylinder removal sensor  199  may be employed to detect a CO 2  cylinder removal or insertion. Cylinder removal sensor  199  may be any suitable sensing device, such as, for example, a switch, or a capacitive or other proximity sensor. 
     Measuring current levels CO 2  in cylinders  30  and/or water bottles  50  as a function of the time that gas release valve  40  is open may provide suitably accurate estimates to a user regarding the level of carbonation in water bottle  50  and/or the remaining level of CO 2  in cylinder  30 . However, the accuracy of such measurements may still be affected by a number of variable factors. For example, there may be: uneven CO 2  release rates in the beginning and/or the end of the push and release action of lever  10 , variation among styles and strengths of pushing the lever  10  by different users, and/or variation in tolerances of parts size and location among different batches of machine assemblies. Any one or a combination of two or more of these factors may impact on the calculation of CO 2  levels as a function of time alone. 
     Therefore, in accordance with another embodiment of the invention, processing unit  170  may also comprise a weighted average calculator  172  which may employ a learning process to compensate for possible variations in actual CO 2  gas release rates. Calculator  172  may record and save the total amount of time that CO 2  was released from successive CO 2  cylinders  30  before they were replaced by the user. It may then use a simple weighted average of CO 2  release times for the most recently used cylinders in order to calculate an expected amount of CO 2  release time for the next CO 2  cylinder  30 . Central processing unit  170  may then use the most recent weighted average when calculating CO 2  amounts in water bottle  50  and cylinder  30 . 
     For example, the CO 2  gas in a factory standard CO 2  cylinder may be expected to be released in 100 seconds. However, on a particular machine  200  it may actually take 104-106 seconds to empty a standard cylinder  30 . Calculator  172  may record the actual replacement points (in terms of seconds of gas released) of the last five cylinders, and may calculate an expected capacity for a next cylinder as a simple arithmetic average of the last five said replacement times, together with the factory standard value of 100 seconds. 
     Thus, if T n  may represent the next cylinder&#39;s expected capacity, and t n  may represent the latest readings&#39; arithmetic average, the following may be an exemplary process flow for the calculation of the weighted average: 
     The input representing the insertion of the first cylinder  30  may represent the factory standard value: t 1 =(100)/1; thus T 1 =100 seconds. 
     In actual practice, the first cylinder  30  may be replaced after a total release time of 106 seconds, accordingly: t 2 =(100+106)/2; thus T 2 =103 seconds. 
     The next cylinder  30  may be replaced after a total release time of 105 seconds, accordingly: t 3 =(100+106+105)/3; thus T 3 =103 seconds (rounded). 
     The next cylinder  30  may also be replaced after a total release time of 105 seconds, accordingly: t 4 =(100+106+105+105)/4; thus T 4 =104 seconds (rounded). 
     The next cylinder  30  may be replaced after a total release time of 104 seconds, accordingly: t 5 =(100+106+105+105+104)/5; thus T 5 =104 seconds (rounded). 
     The next cylinder  30  may be replaced after a total release time of 105 seconds, accordingly: t 6 =(100+106+105+105+104+105)/6; thus T 6 =104 seconds (rounded). 
     It will be appreciated that the error as may be represented by the difference “d” between the weighted average and the actual amount of gas remaining in the cylinder may decrease as time progresses. The first cylinder  30  may have been replaced at a difference: d 1 =rt 1 −T 1 =106−100=6. The next cylinder  30  may have been replaced at a difference d 2 =rt 2 −T 2 =105−103=2. Similarly: d 3 =105−103=2; d 4 =104−104=0; and d 5 =105−104=1. 
     The difference sequence in the example may be represented as a diminishing sequence of 6, 2, 2, 0, 1 . . . , which may presumably stabilize around an error of 0-1 seconds, assuming that operating conditions may remain constant. In contrast, a difference sequence using a constant value of 100 seconds (as per the factory standard expectation) may have been as follows: 6, 5, 5, 4, 5 . . . and may have presumably not have improved over time, assuming that operating conditions may remain constant. Accordingly, it will be appreciated that the accuracy of CO 2  level warning indications may be increased by calculator  172 . 
     It will also be appreciated that the factory standard expectation of 100 seconds and the actual times for emptying cylinders  30  may be exemplary. In actual operation the times may differ. Furthermore, the weighted average may be configured to use different numbers of observations in its computations of weighted average. However, it will be appreciated that regardless of the configuration, using a weighted average instead of a factory standard for the expected level of Co 2  in cylinder  30  may provide a more accurate representation to the user. 
     It will be appreciated that weighted average calculator  172  may provide self adjusting functionality to indirect gas meter  155 , enabling it to learn and adjust itself according to its actual usage pattern and specific operating conditions, which may generally be unknown at the time of manufacture. Accordingly, the alerts and readings conveyed to the user of indirect gas meter  155  may become increasingly accurate as time goes by, and the overall performance and usability of home soda machine  200  may be significantly improved. 
     It will be appreciated that the embodiments disclosed hereinabove may represent exemplary configurations of home soda machine  200 ; the invention may also include other configurations for the implementation of indirect gas meter  155  in home soda machine  200 . For example, the functionality of lever sensor  165  to detect the release of CO 2  from gas cylinder  30  may be implemented in a variety of ways, including: a mechanical switch, a magnetic reed switch, a magnet attached to lever  10 , a microphone to detect the sounds of gas moving through valve  40 , a gas flow meter integrated into valve  40  and/or mechanism  20 , a pressure sensor integrated into valve  40  or mechanism  20 , a capacitive or other type of a proximity switch, and/or any combination of the above. 
     Similarly, the invention may include a variety configurations for sensing the removal of cylinder  30 , such as, for example, a mechanical switch such as depicted as cylinder removal sensor  199 , a capacitive or inductive proximity sensor, a reflective optical sensor, detecting significant changes in the volume/pressure of gas flow when lever  10  may be activated—a sudden increase in flow, pressure or volume compared to a previous operation may signify a new, full cylinder is present, and/or any combination of the above. 
     Timer  171  and calculator  172  may be implemented differently as per specific design requirements. For example, one or both may be implemented as separate modules external to processor  170 . 
     In accordance with an embodiment of the invention, home soda machine  200  may be configured to accept gas cylinders  30  of varying sizes. Therefore in accordance with an embodiment of the invention, weighted average calculator  172  may calculate weighted averages for a multiplicity of cylinder sizes. Processor  170  may comprise means for storing recent data for two or more types of gas cylinder  50 . 
     The user may indicate that a replacement gas cylinder  30  may be of a different size by pressing pushbutton  175 . For example, pressing pushbutton  175  for ten seconds or longer may indicate that the value for the current size may be toggled or advanced a size, depending on how many different sized gas cylinders  30  may be usable with machine  200 . Processor  170  may then show the current selected size on display unit  190 . Alternatively, pushbutton  175  may be used in conjunction with display unit  190  to select a current size from a menu. 
     Unless specifically stated otherwise, as apparent from the preceding discussions, it is appreciated that, throughout the specification, discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer, computing system, or similar electronic computing device that manipulates and/or transforms data represented as physical, such as electronic, quantities within the computing system&#39;s registers and/or memories into other data similarly represented as physical quantities within the computing system&#39;s memories, registers or other such information storage, transmission or display devices. 
     Embodiments of the invention may include apparatus for performing the operations herein. This apparatus may be specially constructed for the desired purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, such as, but not limited to, any type of disk, including floppy disks, optical disks, magnetic-optical disks, read-only memories (ROMs), compact disc read-only memories (CD-ROMs), random access memories (RAMs), electrically programmable read-only memories (EPROMs), electrically erasable and programmable read only memories (EEPROMs), magnetic or optical cards, Flash memory, or any other type of media suitable for storing electronic instructions and capable of being coupled to a computer system bus. 
     The processes and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct a more specialized apparatus to perform the desired method. The desired structure for a variety of these systems will appear from the description below. In addition, embodiments of the invention are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the invention as described herein.) 
     While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.