Abstract:
The present invention includes a wireless soil sensor having a curved surface and at least two groups of sensor-pin electrodes. A tine-catching block is disposed within the sensor body, near a top of the sensor to protect against aeration tools damaging components of the sensor. The electrical circuitry and the battery are separately potted in an epoxy material and oriented vertically, creating a central gap through which an incoming aeration tine is directed.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/384,190 filed Sep. 17, 2010 entitled Wireless Soil Moisture Sensor, the contents of which are incorporated in their entirety herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Soil moisture sensors typically include one or more electrodes that are placed in contact with soil at a specific location. A sensor measures electrical values on the electrodes, determines a moisture value, and then communicates these values back to an irrigation controller. 
         [0003]    However, these moisture sensors can be difficult to properly install in the soil. Improper installation can lead to inaccurate or misleading moisture data. Further, these moisture sensors are susceptible to damage from grounds keeping equipment. Such damage can result in water leakage into the soil moisture sensor, damaging the sensitive internal electronics. 
       SUMMARY OF THE INVENTION 
       [0004]    In a preferred embodiment, the present invention comprises a wireless soil sensor having a curved surface and at least two groups of sensor-pin electrodes. A tine-catching block  120  is disposed within the sensor body, near a top of the sensor to protect against aeration tools damaging components of the sensor. The electrical circuitry and the battery are separately potted in an epoxy material and oriented vertically, creating a central gap through which an incoming aeration tine is directed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which 
           [0006]      FIG. 1  illustrates a front perspective view of a wireless moisture sensor according to the present invention; 
           [0007]      FIG. 2  illustrates a back perspective view of the wireless moisture sensor of  FIG. 1 ; 
           [0008]      FIG. 3  illustrates a top view of the wireless moisture sensor of  FIG. 1 ; 
           [0009]      FIG. 4  illustrates a perspective view of the wireless moisture sensor of  FIG. 1  in a 4.25″ cylindrical hole; 
           [0010]      FIGS. 5-7  illustrate various views of a front case member of the wireless moisture sensor of  FIG. 1 ; 
           [0011]      FIG. 8  illustrates a top view of a back case member of the wireless moisture sensor of  FIG. 1 ; 
           [0012]      FIG. 9  illustrates a bottom view of a back case member of the wireless moisture sensor of  FIG. 1 ; 
           [0013]      FIG. 10  illustrates a cross sectional view taken along line  10 - 10  in  FIG. 9 ; 
           [0014]      FIG. 11  illustrates a cross sectional view taken along line  11 - 11  in  FIG. 9 ; 
           [0015]      FIG. 12  illustrates a cross sectional end view of the back case member of the wireless moisture sensor of  FIG. 1 ; 
           [0016]      FIG. 13  illustrates a top view of an opened wireless moisture sensor of  FIG. 1 ; and, 
           [0017]      FIG. 14  illustrates a tine-catching block within a top portion of the wireless moisture sensor of  FIG. 1 . 
           [0018]      FIG. 15  illustrates a cross sectional view of a member of the tine-catching block of  FIG. 14 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0019]    Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements. 
         [0020]      FIGS. 1-14  illustrates various views of a wireless soil moisture sensor  100  according to the present invention. As discussed in greater detail below, aspects of the sensor  100  allow for improved installation into a soil location resulting in more representative soil measurements. Additionally, other aspects allow for greater damage resistance, especially from turf maintenance equipment (e.g., soil aerators, mowers, etc.). 
         [0021]    As best seen in  FIGS. 1-3 , the sensor  100  comprises an outer casing or body that is formed by a generally flat, back case member  102  and a relatively curved or partially cylindrical front case member  106 . Both case members  102  and  106  are preferably coupled together with screws  110 , a silicon seal and a tongue-in-groove coupling along an outer perimeter of the case members  102  and  106 . 
         [0022]    The front case member  106  also includes a top row of elongated electrodes  104  and a bottom row of elongated electrodes  108 . Preferably, each row includes three electrodes, which allow internal sensor circuitry to measure soil moisture and soil salinity. As seen in  FIG. 3 , the ends of these electrodes  104 ,  108  are preferably even with each other (i.e., they have varying lengths to compensate for the curved surface of the front case member  106 ). However, the electrodes may also have the same length such that the middle electrodes extend further than those on the ends (i.e., following the curve). 
         [0023]    Preferably, the front case member  106  is curved such that it matches the curve of a hole created by a golf course “cup cutting” tool. For example, the curve may match that of a 4.25″ hole, commonly used on golf courses. As best seen in  FIG. 4 , the sensor  100  is placed within the 4.25″ hole  10  such that the curved surface of the case member  106  is pressed against the curved sidewall of the hole  10 . In this respect, the electrodes  104  and  108  infiltrate undisturbed areas of soil adjacent to the hole. Since the soil adjacent to the hole is undisturbed, it will likely provide a more representative measurement of the nearby soil compared with a measurement from disturbed soil filled in immediately around the body of the sensor  100 . 
         [0024]    Preferably, the top sensor pins  104  are positioned between about 2-4 inches from the top of the ground (length  12 ). The bottom sensor pins  108  are preferably located about 5″ below the top pins  104  (length  14 ) and therefore may be located between about 7-9″ from the top of the ground (length  16 ). This positioning typically locates the top sensor pins  104  in the center of the root zone for the grass or similar turf while the lower sensor pins  108  may be located below near the lower end of the root zone to help track salt build-up and infiltration rates. Often, compressed and uncompressed soil will retain different amounts of water. 
         [0025]      FIGS. 5-7  illustrate various views of the front case member  106 . Preferably the front case member  106  forms a partial inner cavity or space for storing the internal components of the sensor  100 . Similarly, as best seen in  FIG. 8-12 , the back case member  102  forms an outer partial cavity  111  and an inner partial cavity  112 . Preferably, the front case member  106  and the back case member  102  include a tongue-in-groove connection around the adjoining regions of the members  102  and  106 . A silicone seal is also preferably positioned within the tongue-in-groove connection or adjacent to it. 
         [0026]    As previously mentioned, the sensor  100  includes features that better resist damage common to turf maintenance machines, especially those used at golf courses. One particularly damaging device used to maintain turf is an aeration tool, which typically employs elongated spikes or tines that are forced several inches into the ground. 
         [0027]    As best seen in  FIGS. 13 and 14 , the sensor  100  includes a tine-catching block formed of a first catcher member  120  and a second catcher member  121 . Preferably, the first catcher member  120  is fixed to the front case member  106  and the second catcher member  121  is fixed to the back case member  102 . The catcher members  120  and  121  preferably each include of a plurality of mating features, such as elongated, longitudinal grooves (e.g., groves  120 A in  FIG. 13 ) on each of the members  120  and  121  that allow the members  120 ,  121  to interlock with each other, as seen in  FIG. 14 . 
         [0028]    The tine-catching block is preferably formed of a shatter-resistant material such as high-density polyethylene (HDPE). Some common plastics like ABS or Polycarbonate can be prone to shattering when impacted with a sharp metal object. In contrast, HDPE is highly resistant to shattering and can thereby absorb the energy of an incoming object. Additionally, HDPE has a dielectric constant that blocks little radio frequency energy (as opposed to metals or similar materials). In this respect, the tine-catching block can absorb the energy of an incoming tine from an aeration tool, preventing the tine from damaging internal components without restricting radio frequency transmissions by the wireless transceiver in the sensor  100 . 
         [0029]    As best seen in  FIG. 13 , some of the internal components of the sensor  100  are arranged in separate vertical areas of the sensor  100 . Specifically, the sensor circuitry  122  (e.g., printed circuit board, microcontroller, sensor circuits) is mounted within a cavity of the front case member  102  while a battery  126  is fixed within compartment  112  in the back case member  106 . When assembled, a gap is formed between the sensor circuitry  122  and the battery  126 , decreasing the likelihood that an incoming tine would strike internal components of the sensor  100 . 
         [0030]    Optionally, the tine-catching block is preferably constructed so as to direct any incoming tines towards the center gap, further reducing any changes of damaging internal components. In one example seen in the cross section view of the catcher member  120  in  FIG. 15 , the tine-catching block can be constructed of thicker areas around its perimeter and a narrower region near its center to help cause deflection of a tine towards the center. In another example, the top surface of the tine-catching block can be angled towards the center and optionally have a hard top layer over the tine-catching block&#39;s perimeter (but not near the center). 
         [0031]    To further minimize damage from tines, the sensor circuitry  122  and batteries  126  are each encapsulated with an epoxy material that helps protect from physical and water damage. Preferably, the epoxy material of the sensor circuitry  122  is separate from the epoxy surrounding the batteries  126 , creating a gap near the center of the sensor  100  (e.g., the width of the gap is between 0.5″ and 2″). The epoxy material helps direct an incoming tine to the gap created between the two epoxy sections while further protecting the components from water damage that may occur after the sensor  100  has been compromised. 
         [0032]    Preferably, an epoxy material is used that does not reduce or hinder sensor readings or radio transmissions. 
         [0033]    The sensor circuitry  122  and batteries  126  are preferably connected via wires  124  which are located near the bottom of the sensor  100 . Hence, an aeration tine would need to pass through the top (i.e., near the tine catching block  120 ) and almost completely through the sensor  100  to damage any of the wires  124 . 
         [0034]    Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.