Abstract:
The present disclosure is directed to systems and methods for pneumatically actuated displays for colored powder. In one illustrative embodiment, an indicator unit includes a hopper into which a dispersible indication powder can be loaded. An air inlet at the bottom of the hopper aligns with a hollow downpipe extending upwards to the top of the hopper. Upon receiving a signal, a burst of air is sent through the air inlet, lifting a portion of the indication powder through the downpipe and into the air above the indicator unit. For use as part of a reactive target system, one or more sensors that can be attached to the back of a target are in communication with the indicator unit and can generate a signal upon sensing a desired condition.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and incorporates by reference all of the subject matter included in Provisional Patent Application Ser. No. 61/882,199, which was filed Sep. 26, 2013. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to pneumatically actuated displays for colored powder, including reactive targeting systems and associated methods. 
       BACKGROUND 
       [0003]    For practicing marksmanship, whether with a bow and arrow, air gun, or firearm, there are primarily two types of targets available for use. Traditional targets, which may be made of paper or plastic and/or steel “gong” targets. These types of traditional targets may be useful for evaluating marksmanship, but often require approaching within a few feet of the target to determine accuracy, which can slow down an event from repeated breaks, or potentially expose a shooter to a dangerous environment. 
         [0004]    Reactive targets have become increasingly popular and provide users an instantaneous reaction to a bulls-eye or direct hit. A typical explosive reactive target consists of a vessel containing a substance that explodes when hit by a bullet and is thus only capable of a single use. A typical mechanical reactive target is knocked down or swung sideways, or has an indicator that lights up to indicate a hit. 
         [0005]    A reactive target system that provides an exciting indication of a hit and can be reused would be an improvement in the art. Similarly, such a system that could differentiate between different types of hits and provide differing feedback would be further improvement in the art. Similarly, a pneumatic display for colored powder that may be used to provide a pyrotechnic type of effect would be a further improvement in the art. 
       SUMMARY 
       [0006]    The present disclosure is directed to systems and methods for pneumatically actuated displays for colored powder. In one illustrative embodiment, an indicator unit includes a hopper into which a dispersible indication powder can be loaded. An air inlet at the bottom of the hopper aligns with a hollow downpipe extending upwards to the top of the hopper, which may have an enlarged lower end. Upon receiving a signal, a burst of air is sent through the air inlet, lifting a portion of the indication powder through the downpipe and into the air above the indicator unit. For use as part of a reactive target system, one or more sensors that can be attached to the back of a target are in communication with the indicator unit and can generate a signal upon sensing a desired condition. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0007]    It will be appreciated by those of ordinary skill in the art that the various drawings are for illustrative purposes only. The nature of the present disclosure, as well as other embodiments, may be more clearly understood by reference to the following detailed description, to the appended claims, and to the several drawings. 
           [0008]      FIGS. 1A and 1B  are top and bottom perspective views of an indicator unit in accordance with a first embodiment of the teachings of this disclosure. 
           [0009]      FIG. 2  is an exploded view of the components of the embodiment of  FIGS. 1A and 1B . 
           [0010]      FIG. 3  is a partial cutaway view of a portion of the embodiment of  FIGS. 1A through 2 . 
           [0011]      FIG. 3A  is a sectional side view of another embodiment of an indicator unit in accordance with the teachings of this disclosure. 
           [0012]      FIG. 4  is a perspective side view of a third embodiment of an indicator unit in accordance with the teachings of this disclosure. 
           [0013]      FIG. 5  is a partial cutaway view of a portion of the embodiment of  FIG. 4 . 
           [0014]      FIGS. 6A ,  6 B,  6 C and  6 D are a top side view, a left side view, a sectional side view (along line A-A of  FIG. 6B ), and a right side view of the embodiments of  FIGS. 4 and 5 . 
           [0015]      FIG. 7  is a bottom perspective view of an embodiment of a sensor unit in accordance with the principles of the present disclosure. 
           [0016]      FIG. 8  is an exploded view of the embodiment of  FIG. 8 . 
           [0017]      FIGS. 9A ,  9 B,  10 , and  11  are graphic illustrations of some functionality of the embodiments of  FIGS. 1  though  8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The present disclosure relates to apparatus, systems and methods related to pneumatic displays and reactive target systems. It will be appreciated by those skilled in the art that the embodiments herein described, while illustrative, are not intended to so limit the scope of the appended claims. Those skilled in the art will also understand that various combinations or modifications of the embodiments presented herein can be made without departing from the scope of this disclosure. All such alternate embodiments are within the scope of the appended claims. 
         [0019]    Referring to the drawing figures,  FIGS. 1A ,  1 B, and  2  depict an indicator assembly  10 A, useful in a system in accordance with the present disclosure. A surrounding frame  100  is used to support and retain the remaining components of the assembly  10 A. As depicted, frame  100  may be formed from one or more pieces, such as right and left stands  100 A and  100 B, which fit together to form the complete frame  100 . 
         [0020]    The frame may include front legs  102  and rear legs  104  to support assembly  10 A for use. It may also include structures for supporting the additional components. For example, hopper support  120  may be formed as a double layered shelf with a hole in the upper layer for insertion of hopper  200  therein, and the upper surface may include recesses  122  for receiving upper supporting tabs  221  disposed around the rim of the hopper  200 . 
         [0021]    A handle  110  may be disposed at the upper surface of frame  100 . The handle may be used for a carrying and positioning the assembly  10 A. A railing  112  may be formed on the handle  110  for receiving an additional accessory. In the depicted embodiment, the railing is a picatinny rail system, such as a 1913 Picatinny rail system. This allows for the mounting of accessories. For example, a UV or an infrared light assembly. Where an indicator powder with florescent properties is used, the light may be reflected by the powder or cause the powder to fluoresce. 
         [0022]    The frame  100  may also include a hood  108  which shelters the attachment for the tank  220  and can provide a panel for control buttons. In the depicted embodiment, the control buttons, include a power switch  304 , such as a rocker switch, a pairing button  306 , and may include other buttons and displays, as for example LED  308 , which can indicate power state, usage, or programming status (e.g., blinking to indicate pairing status). A control board  300 , such as a PCB circuit board contains the necessary circuitry for operation of the unit  100  and in communicative contact with the control buttons. A rechargeable battery  302  may be used to provide power to the unit and can be removably replaced into an appropriate slot on the hood  108 . It will be appreciated that the unit may be powered by any suitable power source and a replaceable/rechargeable battery is only depicted as an illustrative source. 
         [0023]    The hopper  200  may be held in the frame  100  and may have downward sloping sidewalls (along all or a portion of the circumference thereof) leading to a rounded bottom. In the depicted embodiment, the hopper  220  may have a generally conical shape to facilitate the downward movement of the indication powder placed therein. At its upper end, the hopper  200  is closed. In the depicted embodiment, this is accomplished by the hopper lid  204  which attaches to the hopper  200  and may attach to the frame  100  for increased stability of the unit  10 A. An opening or port is disposed in the lid  204 , through which the indication powder may be loaded into the hopper  200 . A cap  208  may be used to seal the port. 
         [0024]    A door  210 , which may function as an outward opening flap or trapdoor is also disposed on lid  204  and acts to close an indication opening. The door  210  may be hingedly attached at one end, as by hinge pin  206 . A down pipe  202  is disposed in the hopper  200  and extends from the indication opening at lid  204  to a distal end near the bottom of the hopper  200 . The space between the down pipe  202  distal end and the bottom of the hopper  200  allows indication powder to enter under the downpipe  202 . A fitting  232  is disposed through the bottom of the hopper  200 , underneath the downpipe  202  such that the bores of the fitting  232  and the down pipe  202  may be generally aligned. 
         [0025]    A tank  220  for storing a pressurized gas, such as air or nitrogen, may be attached to the unit  10 A, by attachment to valve fitting or adaptor  222 , which is in turn attached to a pressure regulator  224 . A pressure line  226 , such as an air hose may extend from the regulator to a gas solenoid  230  (which may require use of a fitting  228 ). The gas solenoid  230  may be attached to fitting  232  for release of pressurized gas into the hopper  200  and may be a 12 volt standard air solenoid. It will be appreciated that an air compressor may be included to keep the tank at a desired charge. 
         [0026]    Referring to  FIG. 3A , a second embodiment of an indicator assembly  10 B, useful in a system in accordance with the present disclosure. The like components of the assembly  10 B to assembly  10 A of  FIGS. 1-3  are indicated with corresponding reference numbers. A surrounding frame  100 A is used to support and retain the remaining components of the assembly  10 B and may include front legs  102 A and rear legs  104 A to support assembly  10 B for use. It may also include structures for supporting the additional components. 
         [0027]    A handle  110 A may be disposed at the upper surface of frame  100 A. The frame  100 A may also include a hood  108 A which shelters the attachment for the tank  220 A and can provide a panel for control buttons. A rechargeable battery  302 A may be used to provide power to the unit and can be removably replaced into an appropriate slot on the hood  108 A. It will be appreciated that the unit may be powered by any suitable power source and a replaceable/rechargeable battery is only depicted as an illustrative source. 
         [0028]    The hopper  200 A may be held in the frame  100 A and may have downward sloping sidewalls (along all or a portion of the circumference thereof) leading to a rounded bottom. In the depicted embodiment, the hopper  220 A may have a generally straight wall  221 A adjacent the front of the assembly and a back wall  223  with a sloped shape (which may include portions having different slopes) to facilitate the downward movement of the indication powder placed therein. At its upper end, the hopper  200 A is closed. In the depicted embodiment, this is accomplished by the hopper lid  204 A. An opening or port is disposed in the lid  204 A, through which the indication powder may be loaded into the hopper  200 A. A cap  208 A may be used to seal the port. 
         [0029]    A down pipe  202 A is disposed in the hopper  200 A and extends from an upper opening above lid  204 A to a distal end. At the distal end, an enlarged bell  203  which may be formed as a funnel is disposed. At the upper end, a small portion  105  of the downpipe  202 A extends above the lid  204 A. A positionable nozzle  107  may be disposed thereon for directing the flow of ejected powder. As depicted, the nozzle  107  may reside in a channel and be rotatable around the upper end of the down pipe. The nozzle  107  may also include a narrowed opening for concentrating a stream of ejected powder. 
         [0030]    The bell  203  is positioned above the bottom of the hopper  200 . The space between the bell  203  and the bottom of the hopper  200  allows indication powder to enter under the bell  203 . A fitting  232  is disposed through the bottom of the hopper  200 , underneath the bell  203  such that the bores of the fitting  232  and the down pipe may be generally aligned. The distance between the bell and  203  and the bottom of the hopper  200 , together with the volume of the bell allows for mixing of gas, such as air, with the powder upon activation as the powder is directed into the downpipe  202 A. In practice, this has been found to reduce the tendency of a portion of the powder lifted by a burst of air to fall back down towards the bottom of the hopper from the pipe  202 A, or in the air over the indicator  10 B. Thus, the use of the bell may reduce “dribbling” resulting in a more visually pleasing display. 
         [0031]    The distance between the rear wall  223  of the hopper and the bell  203  may allow for a feed of powder in the hopper to the space between the bottom of the hopper and the bell  203 . In practice, the sloped wall containing different sloped portions as depicted can allow for a long-running display where gas is allowed to enter through fitting  232  in an ongoing stream and powder flows into the space creating an ongoing display as the powder is ejected through the down pipe  202 A. 
         [0032]    The distance between the bell  203  and hopper  200  may be adjustable where the system  10 A will be used in different conditions. This can account for humidity difference that may affect the weight of a given volume of powder. For most uses, a standard preset distance may be sufficient. For example, where the hopper has a diameter  215  near the bottom of about 4 inches, the bell could be positioned from about 3 to about 4 inches, or at about 3.3 to 3.5 inches above the bottom. Similarly, the distance  205  between the bell and the back wall  223  may be from about 0.5 to about 1.0 inches or from about 0.7 to about 0.8 inches to allow for powder to properly flow below the bell  203 . It will be appreciated these distances are only exemplary and the relationship may need to vary as the size of a system may vary. 
         [0033]    System  10 B may further include a tank  220 A for storing a pressurized gas, such as air or nitrogen, may be attached to the unit  10 , by attachment to valve fitting  222 A, which may include a pressure regulator. A pressure line  226 A, such as an air hose may extend from the valve fitting/regulator to a gas solenoid  230 A. The gas solenoid  230 A may be attached to fitting  232  (as through fitting  228 ) for release of pressurized gas into the hopper  200 A. 
         [0034]    In some illustrative embodiments, the hopper  200  or  200 A may hold approximately six lbs. of indication powder, in other embodiments, the hopper may hold more powder, such as ten or twenty pounds. The indication powder may be a mixture of cornstarch and brightly colored dyes, similar to that used in Hare Krishna color festivals (Holi Color powder). It will be appreciated that flour, talcum powder or other suitable powders may be used. One advantage of an edible powder is that due to the biodegradable nature of the material, no cleanup following usage may be required. The indication powder may be loaded into the hopper via the opening under the fill cap  208  or  208 A. 
         [0035]    Compressed gas, such as air or nitrogen, is used as the propellant to expel the indication powder upwards through downpipe  202 A and vertically into the air. Compressed gas in storage tank  220  (such as a paintball tank), is attached to the intake valve  222  and flows therethrough to regulator  224  (or the combined fitting  222 A). In some illustrative embodiments, the pressure in the tank may be up to about 4500 PSI and delivered from tank by its built-in regulator at about 800 PSI. This is then reduced to from about 200 PSI to about 150 PSI by the regulator  224  or  222 A. The gas then flows through the pressure line  226  or  226 A to the solenoid  230  or  230 A. When the solenoid receives a signal from the board it releases a burst of gas into the hopper through the fitting  232  or  232 A, by allowing a brief burst of gas to pass therethrough. In one illustrative embodiment, the burst may be for a time period of about 75 milliseconds. The indication powder between the fitting  232  and downpipe  202  (which may be ¾ inch in diameter) is lifted through the downpipe  202  bore, past lid  204  and into the air above the unit. This produces a colorful display that may be up to 20 to 25 feet high. Where the assembly  10 A or  10 B is placed behind a berm, only the indication may be visible. The sudden appearance of the indication may produce an effect similar to an explosive reactive target. 
         [0036]    In a second illustrative embodiment, the burst may be for a time period of about 80 milliseconds. The indication powder between the fitting  232  and bell  203  mixes in the bell  203  then is lifted through the downpipe  202 A bore, past lid  204 A and through nozzle  107  and into the air above the unit. This produces a colorful display that may extend up to 20 to 25 feet away in a desired position. 
         [0037]    In a third illustrative embodiment, the burst may be a continuous stream of gas passing through the fitting  232 . The indication powder between the fitting  232  and bell  203  mixes in the bell  203  then is lifted through the downpipe  202 A bore, past lid  204 A and through nozzle  107  and into the air above the unit. As the powder is removed, additional powder flows between the wall of the hopper  200 A and the bell  203  into the space between the fitting  232  and the bell  203  where it mixes and is lifted through the downpipe bore  202 A. This produces an ongoing colorful display that may extend up to 20 to 25 feet away in a desired position. 
         [0038]    Referring to the  FIGS. 4 through 6D , another embodiment of an indicator assembly  100 , useful in a system in accordance with the present disclosure is depicted. A surrounding frame  1000  is used to support and retain the remaining components of the assembly  10 C. In the depicted embodiment, the frame  1000  may be formed as a closed box that supports and retains the remaining components for use. It may also include structures for supporting the additional components. For example, internal braces may be used as a hopper support  2003 , a tank frame  2005  and an accumulator support  2001 . Each of these may attach to the bottom or side of the frame  1000  and receive or support the respective component. 
         [0039]    Where frame  1000  is formed as a closed box, it may be constructed similar to a “flight case” for storage of theatrical or musical equipment to facilitate transport, storage and use. One or more handles  1010  may be disposed on the frame  1000  for carrying and positioning the assembly  10 C. Similarly, one or more wheels  1001  may be attached to the frame  1000  to facilitate transport, as with known “flight cases” or luggage and multiple legs  1002  may be present for support. A control panel  7000  may also be accessible on the frame  1000 , and may have a protective removable or hinged cover  1007 . Control panel  7000  will be discussed in more detail below. 
         [0040]    The hopper  2000  may be held in the frame  1000  and may have downward sloping sidewalls (along all or a portion of the circumference thereof) towards the bottom. In the depicted embodiment, the hopper  2000  may have a generally conical shape to facilitate the downward movement of the indication powder placed therein. At the lower end the hopper  2000  may include a chamber  2007  which may be formed as a vertical tube. 
         [0041]    At its upper end, the hopper  2000  is closed. In the depicted embodiment, this is accomplished by a lid  1003  which may be a planar member that serves as the upper surface of assembly  10 C by enclosing the top of the “box” of the frame  1000 . The lid  1003  may be removable for maintenance. An opening or port is disposed in the lid  1003 , through which indication powder may be loaded into the hopper  2000 . A cap  2008  may be used to seal the port. 
         [0042]    A down pipe  2012  is disposed in the hopper  2000  and extends from an upper opening above lid  1003  to a distal end. At the distal end, an enlarged bell  2013  which may be formed as a funnel may be disposed. At the upper end, a small portion  2015  of the downpipe  2012  extends above the lid  1003 . A positionable nozzle  2017  may be disposed thereon for directing the flow of ejected powder. As depicted, the nozzle  2017  may reside in a channel and be rotatable around the upper end of the down pipe  2012 . The nozzle  2017  may also include a narrowed opening for concentrating a stream of ejected powder. 
         [0043]    Where present, the bell  2013  positioned above the bottom of the hopper  2000 , with the bore of the downpipe  2012  generally aligned with the bore of the chamber  2003 . The bell  2013  may include a number of vent holes  2019  through the sidewalls therein. The number and size of the vent holes  2019  may be varied to achieve desired performance as the gas, indication powder, and pressures used may vary with different embodiments. The bore of the downpipe  2012  is typically larger that the bore of the chamber  2003  to facilitate operation. 
         [0044]    The space between the bottom of the downpipe  2012  (which may be the bell  2013 ) and the sidewalls of the hopper  2000  allows indication powder to enter under the downpipe and into the chamber  2003 . At the bottom of hopper  2000 , a fitting  2032  is disposed through the bottom of the chamber  2003 , such that the bores of the fitting  2032 , the chamber  2003 , and the down pipe  2012  may be generally aligned. The distance between the bell  2013  and the chamber  2003 , together with the volume of the bell allows for mixing of gas, such as air, with the powder upon activation as the powder is directed into the downpipe  2012 . In practice, this has been found to reduce the tendency of a portion of the powder lifted by a burst of air to fall back down towards the bottom of the hopper from the pipe  2012  or in the air over the indicator  10 C. Thus, the use of the bell may reduce “dribbling” resulting in a more visually pleasing display. 
         [0045]    Additionally, the vent holes  2015  have been found to facilitate movement of the indication powder in the hopper into the chamber  2003  by dispersing and aerating the powder around the bell  2013  during operation. 
         [0046]    Similarly, the use of a tubular chamber  2003  has been found to achieve an increased height in the burst of the powder displayed by the assembly  10 C by preloading a fixed amount of powder in a bore aligned with the downtube  2012  bore and the fitting  2032  bore, allowing the majority of the force from a gas burst to propel the powder upwards and out the downtube  2012 , rather than around the hopper  2000 . 
         [0047]    In various embodiments, the size of the bell  2013  may vary in correlation with the size of the chamber  2003  and the hopper  2000 . This is to keep a gap of proer size between the bell  2013  and the hopper in order to achieve proper loading of the chamber  2003  with indication powder. This allows the chamber  2003  to be smoothly loaded by gravity and for the bore of the downtube and bell not to be overwhelmed by the amount of powder therein. Where the indication powder is cornstarch, the adhesive properties of the cornstarch may require a gap of from about ¾ inch to about ½ inch in order to provide proper flow on a hopper having a capacity of about 15-20 lbs. of powder. 
         [0048]    A tank  2200  for storing a pressurized gas, such as air or nitrogen, may be attached to the unit  10 C. The tank  2200  may reside in a tank compartment  1030 , which may be closable with a door forming a surface of the frame  1000 . The tank compartment  1030  may include a support  2005  for the tank  2200 . In some embodiments, the tank may be a SCBA tank with a fitting  2201  reducing the opening to allow attachment to a standard paintball valve to act as a tank valve  2202 . 
         [0049]    The tank valve  2202  may be connected to an intake valve  2222 , which may be a pressure regulating valve, which is in turn attached to a pressure regulator  2226  by a first pressure line  2224 . The pressure regulator  2226  may be adjustable as by a knob  2227  to allow for fine tuning of the air pressure. In some embodiments, the pressure regulator  2226  may only be accessible through an opening or port in the tank compartment  1030  to discourage adjustment by casual users rather than technicians. 
         [0050]    A second pressure line  2228 , such as an air hose may extend from the regulator  2226  to an accumulator  2230 , via a fitting  2229 . The accumulator  2230  may be formed as an enlarged tube for accumulating a mass of gas at a desired pressure for use. For example, where pressurized air may flow from the tank  2200  through the intake valve  2222  at a pressure of about 300 PSI, the pressure regulator  2226  may reduce the pressure going into the second pressure line  2228  and the accumulator to from about 120 to about 150 PSI, as may be adjusted for use. The accumulator  2230  allows for the accumulation of a volume of the reduced pressure gas. 
         [0051]    In the depicted embodiment, the accumulator  2230  may have a bore of about 3 inches and a length of about 14 to about 15 inches, although it will be appreciated that other dimensions may be used. A rigid U-shaped pipe  2232  may connect the accumulator to a gas solenoid  2240 . The gas solenoid  2240  may be attached to fitting  2032  for release of pressurized gas into the hopper  2000  and may be a 12 volt standard air solenoid. It will be appreciated that an air compressor may be included to keep the tank at a desired charge. 
         [0052]    A control panel  7000  may also be accessible on the frame disposed on one surface of the “box”  1000 . In the depicted embodiment, control panel  7000  may be the control buttons, include a number of switches, buttons, sliders for various functions and displays, as for example LED display  7004 , which can indicate power state, usage, or programming status, or control status. Additionally, one more ports  7006  or  7008  may be included for allowing connection via cables. In the depicted embodiment, ports  7006  may be DMX ports and port  7008  may be a power port to allow for recharging of an internal battery, or may be a serial, USB or other port. A control board, such as a PCB circuit board contains the necessary circuitry for operation of the unit  10 C and is in communicative contact with the control buttons, LED display  7004 , and the ports  7006  and  7008 . A rechargeable battery may be used to provide power to the unit and can be removably replaced into an appropriate receptacle on panel  7000  rear surface. It will be appreciated that the unit may be powered by any suitable power source and a replaceable/rechargeable battery is only depicted as an illustrative source. 
         [0053]    In some illustrative embodiments, the hopper  2000  may hold approximately six lbs of indication powder, as discussed previously herein, which may be loaded into the hopper  2000  via the opening under the fill cap  2008 . In other embodiments with a larger hopper ten, fifteen, or twenty pounds of indication powder may be contained therein. 
         [0054]    Compressed gas, such as air or nitrogen, is used as the propellant to expel the indication powder upwards through downpipe  2012  and vertically into the air. Compressed gas in storage tank  2200 , attached to the intake valve  2222  and flows through to regulator  2226  and therethrough to the accumulator  2230 . The gas then flows through the U-shaped pipe  2232  to the solenoid  2240 . When the solenoid receives a signal from the control board  7003  it releases a burst of gas into the hopper  2000  through the fitting  2032 , by allowing a brief burst of gas to pass therethrough. In one illustrative embodiment, the burst may be for a time period of from about 30 to about 75 milliseconds, often from about 35 to about 55 milliseconds. The indication powder between the fitting  2032  and downpipe  2012 , especially that contained in chamber  2007 , may be lifted through the downpipe  2007  bore, past lid  1003  and into the air above the unit. Where the chamber  2007  holds about 7 ounces of powder, the produced display may be up to 20 to 25 feet high or taller. Gas passing through vent holes  2019  may aerate powder in the hopper  2000  and facilitate refilling of the chamber  2007 , allowing a subsequent activation in as little as about 300 milliseconds. This can allow for repeated activations to be timed to music or for control. 
         [0055]    Where the indication powder is cornstarch or colored cornstarch, it has been found that due to the cohesive properties of the cornstarch, that upon actuation, the powder in tubular chamber  2003  may initially behave similar to a solid mass, shearing from the remaining powder in the hopper  2000  and moving upwards as a column or block when gas passing through fitting  2032  forces it upwards. The resulting empty space is then filled by powder that falls downwards, encouraged by the slope of the hopper  2000  sidewall and any movement caused by aeration through vent holes  2015 . Similarly, in embodiments more similar to those depicted in  FIGS. 1A through 3A , the powder between the downpipe  202  and bottom of the hopper  200  above the fitting  232  may react in the same manner. This allows for continued movement of the powder into the position for actuation without the need for an active mechanical loading mechanism, such as an auger. 
         [0056]    Where DMX ports  7006  are present, the control board may allow the unit  10 C to communicate with DMX compliant controllers, such as those employing the DMX  512  standard, or other known standards. For such units the LED readout may be used to assign an address to the unit for the controller and the unit  10 C may be “daisy-chained” to other units  10 C or to other DMX compliant equipment. 
         [0057]    It will be appreciated that other embodiments of systems in accordance with the present disclosure may include multiple hoppers, with associated downpipes and fittings in a single case and controlled by a single control panel. Such embodiments could include separate pressurized gas systems that use individual sources of a pressurized gas, or could use a single system with multiple outputs to fittings from a single source, such as a pressurized tank. This could allow a single system to provide multiple colors or effects. For example, where the individual hoppers are loaded with different colored powders, individual activation of each hopper could allow for different color displays by the single system. Where the different hoppers are actuated simultaneously, a multiple color effect could be had. If the downpipes are directed to a common pathway, such as by using a manifold or suitable nozzles, the colors could appear to be blended to an observer, allowing for additional colors to be created by the mixing of individual indication powders. 
         [0058]    Turning to  FIGS. 7 and 8 , one illustrative embodiment of a sensor assembly  40  for use in a system with an indicator assembly in accordance with the principles of this disclosure is depicted. A housing  400  may be generally formed as a box or other enclosure body with a housing lid  402  and a removable battery door  404 . A battery housing  410  may be provided, or the housing may directly hold batteries or another power source may be used. A circuit board  412 , such as a PCB with desired components may be placed in the housing  400 . A hook and loop fabric system, such as Velcro® patches, maybe used for fastening the sensor assembly  40  to a target. For example, a piece of “hook” fabric  450  may be adhered to the rear of the assembly  40 , and multiple pieces  452  of “loop” fabric may be provided for adhering to the rear surface of targets. 
         [0059]    The circuit board  412 , in one illustrative embodiment may include a microcontroller, accelerometer, a transceiver (such as a radio transceiver or a Bluetooth transceiver), as well as a user interface button and an LED. By default, the sensor assembly  40  may stay in a low power mode until a user presses the user interface button. When the button is pressed, the microcontroller uses the radio to attempt to establish a radio link to an indicator assembly  10  (which may be  10 A,  10 B,  10 C discussed herein or another indicator assembly in accordance with the present disclosure). Once linked, the sensor assembly  40  responds to indicator assembly  10  requests for total hit count. A hit may be detected by processing accelerometer data. 
         [0060]    In certain embodiments, the sensor assembly  40  may be configured to act as a remote control, such that holding the user interface button for a predetermined time may cause the indicator assembly  10  to actuate remotely. 
         [0061]    When the sensor assembly  40  is active, the microcontroller may continually read accelerometer data. It may first compute an exponential moving average (EMA) on the raw data and then calculate the derivative and absolute value of the averaged data. When the absolute value exceeds a set threshold, a hit is detected. Another hit is not detected until the data stream has settled below a threshold. 
         [0062]    The counterpart control board  300  in an indicator assembly  10  may include a microcontroller, solenoid driver, a radio transceiver and/or a Bluetooth receiver, as well as a user interface button and an LED. At startup, the indicator assembly  10  searches for devices (sensors assemblies  40  or other indicators) using the radio. A user may be able to set up the indicator assembly as a slave or master using the user interface button  306 . Once the radio link is established with any available devices, the master may send hit count requests to any sensor assemblies  40  in the network. When the hit count of a sensor assembly  40  increments, the indicator assembly  10  activates the solenoid  230  such that the solenoid activation count matches the sensor hit count. A master indicator assembly  10  can also signal slave indicator assemblies  10  to activate their respective solenoids  230  either in place of or in addition to activating the master solenoid  230 . 
         [0063]    As graphically indicated in  FIG. 9A , a number of sensor assemblies  40 , such as three, can be paired to a single indicator assembly  10 . This may allow a single indicator assembly to provide a hit indication on multiple targets. Similarly, in  FIG. 9B , a single sensor assembly  40  may be paired with a number of indicator assemblies  10 . This can allow a single target to generate different indications. For example, different numbers of hits may generate indications from different indicator assemblies, thus varying the color or intensity of the indication (as where two indicator assemblies  10  are actuated simultaneously). Where the sensor assembly is able to read accelerometer data to determine a relative distance of the hit on the target with respect to the sensor  40 , different indications may be made for different hits. 
         [0064]    As graphically depicted in  FIG. 10 , multiple sensor assemblies  40 A and  40 B may be used on a single target to more accurately sense the position of a hit on that target. This allows for different indications to be provided based on the position of a hit. Where a single indicator assembly  10  is used, this may be different number of indications per hit. Where multiple indicator assemblies  10 A and  10 B are used, it may include different indications from different assemblies  10 . 
         [0065]      FIG. 11  graphically depicts one method of controlling a system in accordance with this disclosure using a Smartphone SP. An application on the Smartphone SP is used to communicate with sensor assemblies  40  and/or indicator assemblies  10  through the Bluetooth radio connection. The Smartphone app allows for programming different indications based on different hits, for example, indications after a certain number of hits, or different indications based on different hit locations. It also allows for direct actuation, such as a single actuation or a series of bursts. It can also allow for preprogrammed indications or timed ones. It will be appreciated that the indicator assemblies  10  may also be used without the sensor assemblies. For example, to provide a display at a color run or in a color festival. For such use, the DMX communication capability discussed in connection with control panel  7000  may be the preferred method of control. 
         [0066]    While this disclosure has been described using certain embodiments, it will be appreciated that the teachings herein may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of this disclosure which use its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practices in the art to which this disclosure pertains and which fall within the limits of the appended claims.