Patent Publication Number: US-2018052033-A1

Title: Low Salt Alert System

Description:
INTRODUCTION 
     Some water softening systems include a brine tank in fluid communication with a mineral tank. The mineral tank typically includes an ion-exchange resin that requires periodic regeneration. The resin is regenerated with a brine solution containing a salt, such as NaCl, whereby the Na +  and Cl −  ions replace mineral ions in the resin, such as Ca 2+  and CO 3   2− . Other media can also be used, such as potassium chloride. 
     The brine solution is produced in the brine tank typically by the dissolution of salt pellets stored therein. Because the salt pellets dissolve, a user must periodically add salt to the brine tank. If the amount of salt pellets in the brine tank falls below a particular level, the water softening unit will not function properly and could even be damaged, requiring expensive servicing, replacement of the entire system and/or and damage to the pipes and water-using appliances in the building. 
     SUMMARY 
     In one aspect, a brine tank salt level detection apparatus includes an infrared emitter, an infrared sensor, a housing supporting the infrared emitter and the infrared sensor, where the housing is configured to be secured to a lid of a brine tank; at least one processor in communication with the infrared emitter and the infrared sensor; and a memory device in communication with the processor, where the memory device stores instructions that, when executed by the processor, cause the apparatus to: emit an infrared signal, receive a reflected infrared signal; and determine whether a salt level in the brine tank is below a predetermined level based at least in part on the receipt of the reflected infrared signal. 
     The infrared emitter can be an infrared light emitting diode that is configured to emit an infrared signal every about 24 hours. The longitudinal axis of the infrared emitter can be aligned substantially normal to the brine tank lid. The housing can also include a mounting cylinder and a nut that secures the housing to the brine tank lid. The apparatus can also include a wireless communication module in electrical communication with the processor and the memory device, where the wireless communication module is configured to transmit a low salt level alert received from the processor. A notification LED can be configured to be illuminated when the processor determines that the salt level is below the predetermined level. The predetermined level can be anywhere from about 20 inches from the top of the tank to about 34 inches from the top of the tank. The processor can determine the salt level in the brine tank at least in part based on whether the infrared sensor detected one or more reflected infrared signals. 
     In another aspect, a method for determining a salt level in a brine tank is disclosed. The method includes emitting an outgoing infrared signal, receiving an incoming infrared signal, determining whether the salt level is below a predetermined level based at least in part on the receipt of the incoming infrared signal, and when the salt level is below a predetermined level, alerting a user of the low salt level in the brine tank. 
     The method can additionally include illuminating a notification light emitting diode when the salt level is below the predetermined level. The incoming infrared signal can be a reflection from the salt in the brine tank. Determining whether the salt level is below the predetermined level can include determining whether an infrared sensor detected one or more reflected infrared signals. Also, determining whether the salt level is below the predetermined level can also include receiving an indication of a brine tank size and, when the infrared emitter emits the outgoing infrared signal, adjusting a power supplied to the infrared emitter based on the brine tank size. Alerting the user can include transmitting a message via a wireless network. The infrared signal can be emitted about every 24 hours and the message can be transmitted about every 24 hours. Alerting the user can also include illuminating a notification light emitting diode when the salt level is below the predetermined level. The infrared signal can be emitted by an infrared light emitting diode with a longitudinal axis oriented substantially normal to the lid of the brine tank. 
     In yet another aspect, a system for notifying a user of a low salt level in a brine tank is disclosed. The system can include an infrared light emitting diode, an infrared sensor, a visible light emitting diode, a computing device in communication with the infrared LED, the visible light emitting diode and the infrared sensor, and a housing supporting the infrared LED, the infrared sensor, the visible light emitting diode and the computing device. 
     The computing device includes a processor, a memory and a wireless module. The memory stores instructions that, when executed by the processor, cause the system to: periodically emit an infrared signal into the brine tank, receive a reflected infrared signal, determine whether a salt level in the brine tank is below a predetermined level based at least in part on the receipt of the reflected infrared signal, transmit a low salt level alert via the wireless module when the salt level in the brine tank is below the predetermined level, and illuminate the visible light emitting diode when the salt level in the brine tank is below the predetermined level. 
     The low salt alert can be sent to a cloud server and can be sent when the salt level is less than about 20 inches from the top of the tank. A portion of the housing can be sized to pass through a circular cutout in a brine tank lid, where the circular cutout is about 2.5 inch in diameter. The system can also include a brine tank size indicator, where the processor uses an indication of a size of the brine tank to determine whether a salt level in the brine tank is below the predetermined level. 
     The infrared signal can be emitted every about 24 hours. The infrared light emitting diode can be positioned normal to a base of the brine tank. The visible light emitting diode can be configured to flash when the salt level is below the predetermined level. Also, the processor can determine the salt level in the brine tank at least in part based on whether the infrared sensor detected one or more reflected infrared signals. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       The following figures, which form a part of this application, are illustrative of described technology and are not meant to limit the scope of the claims in any manner, which scope shall be based on the claims appended hereto. 
         FIG. 1  is a block diagram of an environment for an embodiment of an example low salt detection system; 
         FIG. 2  is a block diagram of an embodiment of an example low salt detection system; 
         FIG. 3  is an embodiment of an example method for determining whether a salt level in a brine tank is below a predetermined level; 
         FIG. 5  is an illustration of a water softening system with an embodiment of an example low salt detection system; 
         FIG. 6  is an isometric, exploded view of an embodiment of an example low salt detection unit; 
         FIG. 7  is an example computing device used within the low salt detection system; and 
         FIG. 8  is a circuit diagram of an embodiment of an example low salt detection unit. 
         FIG. 9  is a circuit diagram of a second embodiment of an example low salt detection unit. 
     
    
    
     DETAILED DESCRIPTION 
     Water softening units are usually located in a basement, garage, or utility room of a building, or outside of the building, and are sometimes elevated above ground level. Unless the owner of the water softening unit regularly checks the brine tank salt level, they may not know when the salt level becomes low in the brine tank and more salt must be added to the tank. A water softening unit operating without the proper amount of salt risks malfunctioning, permanent damage to the unit&#39;s mechanical parts, and damage to the pipes and water-using appliances in the building. Checking the salt level involves removing the brine tank lid and visually observing the salt level. In some regions, the water softening system is elevated off the ground level, which can complicate visual inspection. It is with respect to this general environment that the embodiments of the present application are directed. 
       FIG. 1  is a schematic block diagram illustrating an environment for an example system  100  for alerting a user of a low salt level in a brine tank. The example system includes a user U, an internet-capable user device  104 , a network  110 , and a low salt detection system  102 . Examples of the user U include a homeowner, apartment complex manager, building manager, water conditioning equipment installer or any person who can add salt to the brine tank or communicate a low salt alert to a person such that the salt in the brine tank can be replenished. Other embodiments can include more or fewer components. 
     In the example system  100 , the low salt detection system  102  is in wireless communication with a network  110  over a wireless network. Example wireless networks include Wi-Fi (802.11a/b/g/n), Bluetooth, Bluetooth Low Energy (BLE), Zigbee, Near Field Communication, 6LoWPAN, cellular (e.g. CDMA, GSM, LTE), or other radio frequency communication systems. In the embodiments using Wi-Fi communication, the network includes a wireless router, a wired or wireless modem, or a wireless access point. The wireless communication can occur as signals sent via electromagnetic waves, such as in the form of optical signals or radio frequency (RF) signals. The network  110  can be a combination of more than one type of wireless networks and include the Internet and a Local Area Network. 
     The low salt detection system  102  can communicate with the network  110  using an “internet of things” protocol. For example, in one embodiment the low salt detection system  102  uses MQ Telemetry Transport (MQTT) protocol. The low salt detection system  102  can be programmed to communicate with the Wi-Fi router located in the home or building. Other protocols supporting one-way or two-way communication between the low salt unit and a server are possible. 
     When it determines that there is a low salt condition, the low salt detection system  102  is configured to send a message to the network  110  and then the network  110  sends a message to a user device  104 . The user U receives the message on the user device  104 , which can be a smart phone, tablet computer, smart watch, or other internet-capable computing device. The message can include a unique identifier for the particular tank or user, and a message that the system has detected a low salt condition. Additionally, the message can include an actual salt level as determined by the low salt detection system  102 . 
     The low salt detection system  102  can also include a visual notification component, such as a light-emitting diode (LED), that notifies the user U of a low salt condition in the brine tank. An embodiment of example low salt detection system  102  is shown and described in more detail below with reference to  FIG. 2 . 
     The network  110  can include an electronic notification service that is hosted on a server that is connected to the internet and is located away from and in a different physical location than the network  110 . The server enables low salt detection unit registration and low salt alert notifications. Additionally, the server can track and record salt usage, low salt alert notifications sent, and current salt level. As mentioned above, the messages can be sent over one or more types of networks. 
       FIG. 2  is an embodiment of an example low salt detection system  102 . The example embodiment includes an infrared emitter  130 , an infrared receiver  132 , one or more notification LEDs  134 , power supply  136 , computing device  1800 , wireless module  138  and optional tank size indicator  140 . Each component is in communication, at least, with the computing device  1800 . Other embodiments can include more or fewer components. For example, in an alternate embodiment, the low salt detection system  102  does not include the wireless module  138 . 
     The infrared emitter  130  is configured to emit an infrared signal into the brine tank. In the embodiment of the example system  102 , the infrared emitter  130  is an infrared LED emitter, sized from about 3 mm to about 5 mm, that emits at a wavelength of about 940 nm. However, other sizes can be used with the system, and any wavelength within the infrared and near-infrared spectrum, from about 700 nm to about 1 mm, can be used. In embodiments, the infrared emitter  130  is an LED with relatively low power output. An example of a commercially available infrared emitter  130  is the IR204/H16/L10 3mm Infrared LED, T-1 from Everlight Americas Inc. (Carrollton, Tex.). Other types of infrared emitters can be used, such as an infrared transmitter or other light-emitting components. 
     The infrared receiver  132  is configured to receive an infrared signal. The infrared receiver  132  is an infrared phototransistor in the embodiment of example system  102 . The infrared receiver  132  can be, for example, a 2 mm by 2 mm surface mount resistor, or as large as, for example, a 10 mm LED receiver. Examples of commercially available infrared receivers  132  include the EAIRMDA1 Infrared Receiver Module from Everlight Americas Inc. (Carrollton, Tex.) and the TSOP4138 Infrared Receiver Module available from Vishay Semiconductors (Shelton, Conn.). Other types and sizes of infrared sensors can be used. 
     The one or more notification LEDs  134  include at least one LED for notifying a user of a low salt condition in the brine tank. Each of the one or more notification LEDs  134  may be a multi-die LED. The LED can be configured to flash, blink or display a color, such as red, when the system  102  has detected a low salt condition of the brine tank. In other embodiments, the notification LEDs are any type of visual output component or output panel. 
     The notification LEDs  134  can also include a wireless network connection status LED. The wireless network connection status LED can be configured to illuminate when the system  102  is connected to the wireless network, to flash when attempting to connect to the wireless network, and to be off when the system  102  is not connected to the wireless network. For example, the wireless configuration LED can flash an amber color when the unit is attempting to connect to a wireless network, and remain on when the unit is connected to a wireless network. 
     The notification LEDs  134  can also include a power status LED, where the LED is illuminated when the system  102  has power and is off when the system  102  does not have power. 
     Power supply  136  provides power to the components of the example low salt detection system  102 . In one embodiment, the building mains power provides power to the low salt detection system  102 . In embodiments, the power supply  136  can include a battery source. The low salt detection system  102  can also be configured to be powered via the water softening system. 
     In embodiments of example system  102 , the computing device  1800  is a preprogrammed microprocessor or a system on chip. The same microprocessor controls the infrared signal emission and infrared signal detection discussed below in more detail. 
     The computing device  1800  is in communication with the components of the example low salt detection system  102  and includes at least one processing device  1802 , such as a central processing unit (CPU). A variety of processing devices are available from a variety of manufacturers, for example, Intel or Advanced Micro Devices. In this example, the computing device  1800  also includes a memory device  1804 , and a system bus that couples various system components including the memory device  1804  to the processing device  1802 . The system bus is one of any number of types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. 
     In this example, the computing device  1800  also includes a memory device  1804 , which includes read only memory and random access memory. A basic input/output system containing the basic routines that act to transfer information within computing device  1800 , such as during start up, is typically stored in the read only memory. 
     In some embodiments, computing device  1800  includes input devices to enable the user to provide inputs to the computing device  1800 . Examples of input devices include a touch-sensitive display device, such as an liquid crystal display (LCD) and smart devices, such as smart phones, tablet computers, etc., that can access applications (also called “apps”). 
     The computing device  1800  typically includes at least some form of computer-readable media. Computer readable media includes any available media that can be accessed by the computing device  1800 . By way of example, computer-readable media include computer readable storage media and computer readable communication media. 
     A number of program modules can be stored in a secondary storage device or the memory device  1804 , including an operating system, one or more application programs, other program modules, and program data. The data used by the computing device may be stored at any location in the memory  1804 , such as the program data, or at the secondary storage device. 
     The different components of the low salt alert system, such as the intermediary servers that communicate with the smart devices, can also require maintenance in the form of firmware and software updates. These intermediary servers can be managed by the systems and methods described herein to update the maintenance requirements of the servers. 
     Embodiments of the present invention may be utilized in various distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network in a distributed computing environment. 
     In other embodiments, the computing device  1800  is an embedded micro-controller or system-on-chip (SOC). In still other embodiments, the low salt detection system  102  uses the processor in the wireless module  138  as the processing device  1802 . 
     The wireless module  138  includes an antenna, connects to the wireless network, and enables communication to, and in some embodiments, from, the network. In some embodiments, the wireless module  138  is a system on a chip (SoC). The wireless module  138  can be mounted onto a circuit board. An example wireless module is the Texas Instruments  3200 . 
     The optional tank size indicator  140  is a slide switch, dip switch or other user-input component. The tank size indicator  140  includes a slide switch enabling a user to select a brine tank size, for example, “3-feet,” “3.5-feet” and “4-feet”. In other embodiments, only two brine tank sizes are available for user selection, such as “38 inches” and “44 inches.” The user selects the brine tank size closest to the actual brine tank size. In an embodiment, the tank size indicator  140  can also be configured to receive the tank dimensions from the user. Other sizes are possible. 
     In some embodiments, the low salt detection system  102  includes a salt type indicator. For example, a slide switch that the user can toggle to indicate what type of salt is in the brine tank, such as blocks, pellets, etc. The type of salt may affect the reflection and ultimate reception of emissions by the infrared receiver  132 . 
     In the embodiment of example method  200 , shown and described below with reference to  FIG. 3 , the tank size indicator  140  adjusts the timing that the computing device  1800  uses to determine whether there is a low salt condition in the tank. For example, tank size indicator  140  includes three dip switches labeled “3-feet,” “3.5-feet” and “4-feet”. When the user selects one of those switches that corresponds to the height of their brine tank, the tank size indicator  140  sends a signal to the computing device  1800  to use a particular time for the low salt determination, such as 2 nanoseconds. 
     In the embodiment of example method  300 , shown and described below with reference to  FIG. 4 , the tank size indicator  140  sends a signal to the computing device  1800  to send a specific amount of current to the infrared emitter  130  based on the indicated tank size. Adjusting the power is described in more detail below with reference to operation  304 . 
       FIG. 3  is an embodiment of example method  200  for determining whether there is a low salt condition. The embodiment of the example includes initiating infrared emission (operation  204 ), receiving infrared signal (operation  206 ), receiving brine tank size (operation  209 ), determining whether the salt depth is below a predetermined level (operation  210 ), alerting the user (operation  212 ) and reset (operation  214 ). Other embodiments of example method  200  can include more or fewer operations. 
     The embodiment of example method  200  begins with the infrared emitter emitting an infrared signal into the brine tank (operation  204 ). The computing device that is in communication with the infrared emitter initiates the infrared emission and starts a counter or records the time of emission. This time is used in later operation  210  to determine the time for the signal to be emitted and received at the infrared receiver. Operation  204  can be initiated based on a preset time, such as every about 1 hour, every about 2 hours, every about 4 hours, every about 8 hours, every about 12 hours, every about 18 hours, every about 24 hours, every about 36 hours, or every about 48 hours. 
     After the emission of the infrared signal, the signal is received by the infrared receiver in operation  206 . Without being bound to a particular theory, the infrared signal reflects off the salt in the brine tank and the infrared receiver detects the reflected signal. The computing device records the time the signal was received. Alternatively, the computing device stops the timing that was initiated when the infrared signal was emitted. One or both of these values are stored and used during operation  210 . In some instances, the reflected infrared signal will be too weak to detect. The lack of detection after an emission may also be stored and used during operation  210 . Where there is a detected signal, the strength of that signal may also be stored and used during operation  210 . 
     At some point during or before embodiment of method  200 , the low salt detection system receives a brine tank size (operation  209 ). For example, the user indicates the brine tank size using a dip switch during installation of the low salt detection system. Other configurations for receiving a brine tank size are described above in more detail with reference to  FIG. 2 . The computing device stores the brine tank size and uses the brine tank size during salt level determination operation  210 . That is, the system receives the brine tank size (operation  209 ) once. It will be appreciated, however, that the system can be installed on a different tank, at which point the user will indicate the new tank&#39;s size. 
     After the system has received the brine tank size (operation  209 ) and received the infrared signal (operation  206 ), the next operation in embodiment of method  200  is to determine whether the salt depth is below a predetermined level (operation  210 ). During this operation, the system calculates the time required for the infrared signal to be emitted and then received. For ease of discussion, this time is called the elapsed time. As discussed above, this calculation can include starting and stopping a timer or, alternatively, recording an emission time and a receipt time and subtracting the emission time from the receipt time to yield an elapsed time. 
     When the elapsed time is calculated, the system next determines whether the salt level is below a predetermined level. The predetermined level is a distance from the top of the brine tank to the top of the salt in the brine tank. The predetermined level can be factory pre-set or user-selected. The predetermined level is about 18 inches; about 20 inches; about 24 inches; about 28 inches; about 32 inches; about 34 inches; about 36 inches; or from about 20 inches to about 34 inches from the top of the brine tank. 
     Depending upon the predetermined level selected, a low salt level determination does not mean that more salt must be added immediately. Rather, the low salt level determination, again depending upon the level selected, is a warning that more salt needs to be added within the next approximately 15 to 30 days, assuming normal water use and normal softener regeneration cycles. 
     In embodiments, the computing device is configured to compare the elapsed time to a threshold time. The computing system can set a threshold time based on the brine tank size. For example, the system determines an elapsed time of about 2.4 nanoseconds in a 3-foot brine tank. In this example, the threshold for a low salt condition is about 2 nanoseconds, which corresponds to a salt height of about 24 inches from the top of the brine tank. Because the elapsed time (about 2.4 ns) is greater than the threshold (about 2 ns), the system determines that there is a low salt condition. Other thresholds are possible. 
     In embodiments, the computing device is configured to compare the elapsed time to a list of values correlating time to salt depth for the particular brine tank size. For example, in a 3.5 foot brine tank, an elapsed time of about 2 nanoseconds corresponds to a salt level depth of about 24 inches from the lid of the tank. The computing device then evaluates whether a salt level depth of 24 inches from the lid of the tank is less than the predetermined level. 
     In embodiments, the computing device is configured to calculate the salt depth using the elapsed time. For example, the system multiplies the known velocity of the infrared signal by the elapsed time to yield a distance, d 1 , from the infrared components. The computing system also has the stored brine tank size, d 2 , from operation  209 . The salt depth can then be determined by subtracting d 1  from d 2 . Other methods for determining the salt level are possible. The system can also record, track and save salt level history. 
     In embodiments, the computing device is configured to calculate the salt depth based on the strength or amplitude of the detected signal. The strength of the detected signal may be compared to a predetermined threshold or to the strength of the signal emitted in operation  204 . The predetermined thresholds may be experimentally or analytically derived to correspond to particular levels of salt in a particular sized tank. Similarly, a ratio of the detected signal strength to the emitted signal strength would also indicate a particular salt level for a particular sized tank. The detected salt level is then compared to a predetermined salt level in operation  210  to determine if the current salt depth is below the predetermined level. 
     If a low salt condition is detected, the embodiment of method  200  proceeds to alert the user (operation  212 ). If the salt depth is not below the predetermined level, the embodiment of method  200  returns to initiate infrared emission (operation  204 ). 
     As discussed above with reference to  FIG. 2 , the embodiment of example low salt detection system can include one, or more than one, low salt alert components. In the embodiment of method  200 , the system alerts the user when the system determines in operation  210  that there is a low salt condition. Operation  212  includes illuminating an LED, for example, by flashing the LED. Operation  212  also includes transmitting a low salt condition to the network server, which in turn sends one or more notification messages to the user. 
     Operation  212  can include alerting an electronic notification service by accessing the internet via a Wi-Fi network connection and sending the notification service a unique identifier. The system can be configured to transmit the low salt message or unique identifier daily. 
     Alerting user (operation  212 ) continues until either the user resets the system or salt is added to the brine tank and the system performs the next salt level determination (operation  214 ). 
     The embodiment of example low salt detection system  102  includes a “test” button. In some embodiments, the “test” button is displayed on an optional user interface or on a smart device. Other names of the button are possible. A result of pressing the “test” button is that the unit conducts a salt level check (operations  204 ,  206  and  210 ). If the result of the salt level check is that the salt level is no longer below the threshold level, the LED ceases flashing and the unit will not send another low salt message until it determines that there is a low salt condition. In other embodiments, a result of a user selecting the “test” button is that the unit verifies that it has a proper network connection. If no network connection is detected, or if a network connection is not functional, the user may be notified accordingly. 
       FIG. 4  is an embodiment of example method  300  for determining whether there is a low salt condition. The embodiment of the example includes receiving brine tank size (operation  302 ), initiating infrared emission (operation  304 ), determining whether an infrared signal was detected (operation  308 ), alerting the user (operation  312 ) and reset (operation  214 ). Other embodiments of example method  300  can include more or fewer operations. 
     The embodiment of example method  300  begins with a low salt detection system  102  receiving a brine tank size (operation  302 ). Based on the brine tank size, the low salt detection system  102  adjusts the amount of current that is sent to the infrared emitter. An embodiment of an example configuration for adjusting the amount of current is shown and described below with reference to  FIG. 8 . The current is calibrated based on the power requirements of the infrared emitter, such as a near-infrared light emitting diode. The level of current sent to the LED is based on a predetermined low salt level, such that an emitted infrared signal is not detected by the infrared receiver when the signal travels a determined distance. Without being bound by a particular theory, if the infrared signal travel distance, from the emitter to the salt and back towards the infrared receiver, is greater than a threshold distance, the strength of the infrared signal will diminish to a point where the infrared receiver will not detect the signal. 
     Next, one or more than one infrared emissions are initiated (operation  304 ). For example, a series of eight pulses, at a frequency of between about 32 kHz and about 38 kHz, are emitted in operation  304 . Other pulse frequencies may also be used depending on the embodiment and components utilized. Any number of pulses can be used, for instance, 1 pulse, 2 pulses, 3 pulses, 4 pulses, 5 pulses, 6 pulses, 7 pulses, 8 pulses, 9 pulses, 10 pulses, or more. 
     After each signal is emitted (operation  304 ), the system determines whether an infrared signal was detected by an infrared receiver (operation  308 ). In the example where eight pulses are emitted, the system determines that the brine tank has a low salt condition if less than eight infrared signals are detected by the infrared receiver. The system may also verify that the received frequency matches the emitted frequency. 
     For example, the infrared emitter sends out eight pulses and the infrared receiver detects five pulses. At that point, the system determines that there is a low salt condition because the system received less than all of the infrared signals emitted. In other embodiments, the system determines that the brine tank has a low salt condition using different thresholds for how many of the emitted infrared signals are detected by the infrared receiver. For example, the system determines that there is a low salt condition when five of eight pulses are received, but not when six of eight pulses are received. Other thresholds and numbers of pulses are possible. 
     If the system determines that there is not a low salt condition in operation  308 , then the embodiment of example method  300  returns to operation  304  and the user is not alerted. In embodiments, the system can send a notification to the cloud server that the system does not have a low salt condition. It will be appreciated that the system can be configured to notify the user that there is not a low salt condition. 
     If the system determines that there is a low salt condition in operation  308 , then the embodiment of example method  300  proceeds to alert the user (operation  212 ). Alerting the user (operation  212 ) is described in more detail above with reference to  FIG. 3 . 
     Alerting user (operation  212 ) continues until either the user resets the system or salt is added to the brine tank and the system performs the next salt level determination (operation  214 ). Reset (operation  214 ) is described in more detail above with reference to  FIG. 3 . 
       FIG. 5  is an embodiment of an example water softening system  400 . The embodiment  400  includes a brine tank  402 , a low salt alert unit  404 , wireless communication unit  406 , brine tank lid  408 , control valve  412  and mineral tank  410 . Other embodiments can include more or fewer components. 
     The brine tank  402  is shown as a cylindrical brine tank, which is commonly made of a plastic material. However, the low salt alert unit  404  can be used for a brine tank with any cross-sectional shape, such as rectangular, square, triangular, pentagonal, etc. Additionally, as discussed above, the low salt alert unit  404  can be used with brine tanks  402  of different sizes and materials. 
     In embodiments, the low salt alert unit  404  is installed as a retrofit. That is, the unit  404  is installed after factory production, for example, by a water softener dealer, a home user, etc. An example of a configuration for a retrofitted low salt alert unit  404  is shown and described in more detail below with reference to  FIG. 6 . The low salt alert unit  404  includes the components of low salt detection system  102  described above in more detail with reference to  FIG. 2 . 
     As depicted in  FIGS. 5 and 6 , the low salt alert unit  404  is positioned at or near the centroid of the brine tank lid  408 . Additionally, in the embodiment of example water softening system  400 , the infrared emitter is positioned such that the infrared signal does not pass through the lid of the tank  408  before entering the tank space and reflecting off of the salt. The low salt alert unit  404  is also configured with the infrared receiver positioned to receive infrared signals without the signals first passing through the sides of the tank or the lid of the tank  408 . 
     The low salt alert unit  404  can include a reset button. In embodiments, the reset button is recessed and will require a paper clip or similarly sized object to access. When pressed, the reset button can cause the Wi-Fi module to reset by, for example, cycling the power to a circuit board or the Wi-Fi module. When pressed for more than a specific period of time, for example, two seconds, the reset button can cause the reset of the computing device which erases the Wi-Fi network configurations and brine tank size. 
     The wireless communication unit  406  includes wireless communication components for connecting to a Wi-Fi network. For example, the wireless communication unit  406  includes a Wi-Fi system on a chip (SoC), radio-frequency communication components, and an on-board antenna. An example wireless communication unit  406  is a CC3200 made by Texas Instruments (Dallas, Tex.). 
     The wireless communication unit  406  can alternatively, or additionally, include components compatible with one or more of the following communication protocols: ANT+, Bluetooth Low Energy (BLE), Zigbee, Near-Field Communication (NFC), WiFi Direct, and 6LoWPAN. 
     In the embodiment shown, the control valve  412  and mineral tank  410  are not in communication with the low salt alert unit  404 . Thus, the low salt alert unit  404  does not control the operation of the control valve  412 . In alternate embodiments, the control circuitry for the low salt alert unit  404  is incorporated into the valve, and the regeneration cycle can be stopped when there is a low salt condition. 
       FIG. 6  is an exploded view of an embodiment of an example environment  500  showing a low salt alert unit configured to be secured to a brine tank lid. The embodiment includes a low salt alert unit including: a circuit board  502 , a circuit board housing lid  504 , a circuit board housing base  506 , a power source  508 , and a compression nut  514 . Also shown are a brine tank lid  510  and a cutout  512 . Other embodiments can include more or fewer components. 
     The illustrated circuit board  502  includes LED indicators for power, wireless connectivity and low salt condition. The illustrated circuit board  502  also includes mounted switches for resetting a wireless configuration, cycling the low salt system to determine whether a low salt condition still exists, indicating a brine tank size, and/or sending a test message. Additionally, the circuit board  502  supports the infrared emitter and infrared receiver, which are directed towards the brine tank interior. 
     The circuit board  502  is also configured to receive power from a power source  508 . As illustrated, power source is a 4.5 volt DC overmolded barrel jack. Other power sources are possible, such as 5 volt DC, 12 volt DC, and all voltages therebetween. The DC connection can receive power from building mains or from a control valve/mineral tank assembly. 
     The infrared emitter is aligned on the circuit board  502  such that the infrared signal is emitted normal or substantially normal to the plane of the brine tank lid, which is generally parallel to the surface supporting the brine tank. The infrared receiver is aligned on the circuit board  502  such that the receiving sensor plane is parallel or substantially parallel to the plane of the brine tank lid. 
     The illustrated circuit board housing lid  504  is an optional component that is sized to fit over the circuit board  502 . Additionally, the circuit board housing lid  504  is at least minimally transparent such that the light from the LEDs can be seen while the lid  504  is in place. 
     The circuit board housing base  506  includes a surface which supports the circuit board  502  and a cylindrical portion  507  that is sized to pass through a cutout  512  in the brine tank lid  510 . The circuit board housing base  506  also includes support guides for the infrared emitter and infrared receiver that project downward from the circuit board  502 . These guides are optional. 
     As illustrated, the circuit board housing lid  504  is substantially a rectangular prism and the circuit board housing base  506  is substantially rectangular. Other shapes are possible, such as a cylinder shape for the housing lid  504  and a circular shape for the housing base. 
     As illustrated, the cylindrical portion  507  sized to pass through the cutout  512  is threaded such that a compression nut  514  can be used to secure the circuit board housing base  506  to the brine tank lid  510 . The cylindrical portion  507  can be other shapes as well. In other embodiments, the portion  507  is not threaded and the circuit board housing base  506  is adhered or fastened to the brine tank lid. 
     The brine tank lid  510 , as illustrated, has a square cross-sectional shape. However, the low salt alert system unit can be secured to a brine tank lid with any cross-sectional shape. The cutout  512  in the brine tank lid  510  can be made during or after the lid is manufactured. As illustrated, the cutout  512  is substantially circular and sized to allow the cylindrical portion  507  to pass therethrough. The diameter for the cutout  512  is about 0.5 inch; about 1.0 inch; about 1.25 inches; about 1.45 inches; about 1.5 inches; about 2.0 inches; about 2.5 inches; about 3.0 inches; about 3.5 inches; or about 4.0 inches. 
       FIG. 7  is an embodiment of an example method  600  for installing a low salt detection unit. The embodiment of the example method  600  includes creating a hole (operation  602 ), positioning and securing housing (operation  604 ), setting a tank size (operation  606 ), connecting to a wireless network (operation  608 ), and initiating salt level detection (operation  610 ). The illustrated method is for a user installing a low salt detection system on a post-production brine tank. However, it will be appreciated that the method can be performed during manufacturing or prior to being sold to an end user. Other embodiments can include more or fewer operations. 
     The embodiment of example method begins by creating a hole in the brine tank lid (operation  602 ). The size and shape of the hole in the brine tank should allow for a protruding portion of the circuit board housing to pass through the lid. 
     After a hole has been created in the brine tank lid (operation  602 ), the housing is positioned and secured to the lid (operation  604 ). In the embodiment shown in  FIG. 6 , the protruding portion of the circuit board housing is a threaded cylinder. In this embodiment, the compression nut is used to secure the circuit board housing. In other embodiments, the circuit board housing is secured to the brine tank lid using an adhesive or one or more fasteners. 
     Next, the user sets the brine tank size (operation  606 ). The low salt alert unit includes a dip switch or a slide switch with different brine tank sizes labeled. The user chooses the size corresponding to the brine tank dimensions. In other embodiments, the user indicates the brine tank size using a graphical user interface that is part of the low salt detection unit and/or via a smart apparatus, such as a computer, smart phone, tablet computer, smart watch, etc. 
     After operation  604 , the user also connects the low salt alert unit to a wireless network (operation  608 ). In an embodiment, the wireless network is a Wi-Fi network. The user configures the low salt alert unit with information including a network SSID, a gateway IP address and a password if the network is secured. Commercial protocols that can accomplish this include Wi-Fi Direct, User Datagram Profile, and Texas Instrument&#39;s SmartConfig. In this embodiment, the user accesses an application running on a smart phone, tablet computer, computer or the like, and connects to the Wi-Fi-enabled low salt alert unit and configures the unit with the required network information. In some instances, the same application is used to configure other low salt alert unit information, such as the device name and the internet data server, a service provider, to communicate with. When the low salt alert unit is connected to the wireless network, a notification LED is illuminated. 
     Operation  608  can additionally include the user accessing a cloud server, for example through the internet. There, the user can create an account, register him or herself, the device, enter contact information including phone number and email, and/or select how to receive messages. For example, the user can select to receive either a text message alert, an email alert, or both. The user can also indicate the date of purchase, the frequency of notification alerts, and physical address. 
     Next, the user initiates low salt level monitoring (operation  610 ). An example method for low salt level monitoring is shown and described in more detail above with reference to  FIG. 3 . 
       FIG. 8  is a circuit diagram of an embodiment of an example circuit  800  used in a low salt alert system. The circuit diagram shows resistors R 8  and the parallel combination of R 16  and one of R 11 , R 12  or R 13 , an infrared LED D 6 , field-effect transistor Q 1 , and slide switch SW 3 , among other components. Other embodiments can include more or fewer components. Other values for the components shown in  FIG. 8  are possible. 
     In the embodiment shown, the resistances of R 8 , R 11 , R 12 , R 13  and R 16  are 49.9Ω, 3.83 kΩ, 2.21 kΩ, and 470Ω, respectively. Other resistances are possible. The amount of current through the infrared LED is determined, in part, by R 8  and the parallel combination of R 16  and one of R 11 , R 12 , or R 13 . 
     As shown, the slide switch SW 3  is in a position such that current flows across R 8 , R 11  and R 16  determine the current through the infrared LED. By moving the position of the slide switch, the amount of current flowing across the infrared LED D 6  can be changed or controlled. For example, by moving the switch such that the contacts are on points  2  and  6  rather than  1  and  5 , current flows across R 12  rather than R 11 . Because R 12  and R 11  have different resistances, the current drawn across the infrared LED D 6  is different. By causing a higher level of current to flow across the infrared LED D 6 , a higher strength infrared light signal is emitted from the LED D 6 . As discussed above, the user indicates the brine tank size using the slide switch SW 3 . 
     The circuit is supplied from a 4.5 V power source. As mentioned above, other voltages for the power source are possible, such as voltages from about 4.5 V to about 12 V. Different amounts of supplied voltage are possible depending on the selected components. Q 1  is a field-effect transistor. Activating the transistor Q 1  closes the circuit and allows current to flow across the infrared LED D 6 , thus generating light. The light can be modulated by modulating the voltage on the gate of the transistor Q 1 . For instance, to provide pulsed light, pulsed voltage can be applied to the gate of the transistor Q 1  causing a pulsed current to flow across the infrared LED D 6 . The pulsed voltage on the gate of the transistor Q 1  may come from any suitable source for producing modulated signals from the location depicted as TX in  FIG. 8 . For example, a microprocessor generates a modulated signal that is sent to the gate of the transistor Q 1  via a serial I/O pin. The pulses from the microprocessor may represent a particular character or string of characters, such that when the pulses are eventually detected the emitted character may be compared to the detected character. 
     In alternate embodiments, the low salt alert system can determine that the salt level in the brine tank is within one or more ranges. In those embodiments, the system select from R 11 , R 12 , R 13 , or any additional resistors without user intervention. The system first selects the highest overall resistance and therefore emits an infrared signal with the lowest strength. As long as the system receives one or more reflected signals at that resistance, the system determines that the salt level is in a range, for example, less than about 20 inches from the lid of the brine tank. 
     When the system no longer receives a signal at that resistance, a controller selects a lower overall resistance, resulting in a higher strength infrared signal being emitted. Each overall resistance level corresponds to a particular level of salt for a particular size brine tank. The process repeats and the system determines that the salt level is in a predetermined range, for example, less than about 20 to about 34 inches from the lid of the brine tank, as long as the one or more reflected infrared signals are detected. This process continues for selecting any additional lower overall resistances. It will be appreciated that more resistors can be used in other embodiments, which would narrow the indicated salt level ranges. 
     In embodiments, a variable resistor is used in place of resistors R 11 - 13  and/or R 16  and the slide switch SW 3 . The resistance is selected using an input/output pin on a microprocessor, which automates the resistance selection process. A manual potentiometer or a digital potentiometer can be used. 
     As shown in  FIG. 8 , transistor Q 1  may be a BSS138 N-Channel Logic Level Enhancement Mode Field Effect Transistor commercially available form Fairchild Semiconductor. As also depicted, infrared LED may be an IR204/H16/L10 commercially available from Everlight. Other similar components could be utilized in place of these example components. 
       FIG. 9  is a circuit diagram of a second embodiment of an example circuit  900  used in a low salt alert system. The circuit diagram shows resistors R 8  and the parallel combination of R 16  and one of R 11  or R 12 , infrared LEDs D 6  and D 7 , field-effect transistor Q 1 , and slide switch SW 3 , among other components. Other embodiments can include more or fewer components. Other values for the components shown in  FIG. 9  are possible. 
     The embodiment of example circuit  900  includes two infrared LEDs, D 6  and D 7 . In other embodiments, one infrared LED is used, such as in the embodiment shown in  FIG. 8 . 
     Also, the embodiment of example circuit  900  includes slide switch SW 3  that may be used to select one of two resistors, R 11  or R 12 . In other embodiments, a single resistor is used in parallel with R 16  and those embodiments do not include slide switch. In yet other embodiments, the slide switch may be used to select four or more different resistors. 
     The block diagrams depicted herein are just examples. There may be many variations to these diagrams described therein without departing from the spirit of the disclosure. For instance, components may be added, deleted or modified. 
     As used herein, “about” refers to a degree of deviation based on experimental error typical for the particular property identified. The latitude provided the term “about” will depend on the specific context and particular property and can be readily discerned by those skilled in the art. The term “about” is not intended to either expand or limit the degree of equivalents which may otherwise be afforded a particular value. Further, unless otherwise stated, the term “about” shall expressly include “exactly,” consistent with the discussions regarding ranges and numerical data. Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 4 percent to about 7 percent” should be interpreted to include not only the explicitly recited values of about 4 percent to about 7 percent, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 4.5, 5.25 and 6 and sub-ranges such as from 4-5, from 5-7, and from 5.5-6.5; etc. This same principle applies to ranges reciting only one numerical value. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described. 
     The description and illustration of one or more embodiments provided in this application are not intended to limit or restrict the scope of the invention as claimed in any way. The embodiments, examples, and details provided in this application are considered sufficient to convey possession and enable others to make and use the best mode of claimed invention. The claimed invention should not be construed as being limited to any embodiment, example, or detail provided in this application. Regardless whether shown and described in combination or separately, the various features (both structural and methodological) are intended to be selectively included or omitted to produce an embodiment with a particular set of features. Having been provided with the description and illustration of the present application, one skilled in the art may envision variations, modifications, and alternate embodiments falling within the spirit of the broader aspects of the claimed invention and the general inventive concept embodied in this application that do not depart from the broader scope.