Abstract:
A system for the detection of fast-moving dropping objects includes a submitting plate, a receiving plate, and a microcontroller. The submitting plate includes a first submitting pipe, a second submitting pipe, and a third submitting pipe. The first, second, and third submitting pipes emit infrared rays in turn. The receiving plate includes a first receiving pipe, a second receiving pipe, and a third receiving pipe. An object passage is defined between the receiving plate and the submitting plate, and the activation of the submitting pipes in turn detects individual objects even if one of a number of the falling objects obscures another falling object.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to detection systems, and particularly to a detection system for an object dropping. 
         [0003]    2. Description of Related Art 
         [0004]    Infrared rays are used in various fields, such as vending mechanisms. In a vending mechanism, infrared beams being made or broken determines whether an object is normally out of a passage in the vending mechanism. Generally, the vending mechanism comprises a submitting plate with a submitting module, a receiving plate with a receiving module and a microcontroller. The object path or passage is defined between the submitting plate and the receiving plate. When the object passes through the passage, the infrared ray emitted by the submitting module is transmitted to the receiving module, and the microcontroller records the exit of an object from the passage in the vending mechanism. However, when the object passes through the object passage, the object may break the infrared ray, and the receiving module can not timely receive the infrared ray emitted by the submitting module. Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0006]      FIG. 1  is a block diagram of a detection system in accordance with an embodiment. 
           [0007]      FIG. 2  is a circuit view of the detection system of  FIG. 1 . 
           [0008]      FIG. 3  is a schematic view of the detection system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
         [0010]      FIGS. 1-2  illustrate a detection system in accordance with an embodiment. The detection system defines an object passage  10  and comprises a submitting plate  20 , a receiving plate  30 , a microcontroller  40 , and a plurality of circuit boards  50 . The microcontroller  40  is connected to the submitting plate  20  and the receiving plate  30 , and the plurality of circuit boards  50  are connected to the receiving plate and the microcontroller  40 . In one embodiment, the submitting plate  20  is substantially parallel to the receiving plate  30 , and the plurality of circuit boards  50  comprises eight circuit boards  50 . 
         [0011]    The submitting plate  20  comprises a plurality of submitting pipes, such as eight submitting pipes Q 100 -Q 107  arranged one after the other and located on a first straight line that is substantially parallel to the submitting plate  20 . The receiving plate  30  comprises a plurality of receiving pipes, such as eight receiving pipes Q 200 -Q 207  corresponding to the eight submitting pipes Q 100 -Q 107  and located on a second straight line that is substantially parallel to the receiving plate  30 . In one embodiment, each of the eight receiving pipes Q 200 -Q 207  is an optical coupler. 
         [0012]    Each of the eight receiving pipes Q 200 -Q 207  is connected to a circuit board  50 . For example, the receiving pipe Q 200  is connected to a circuit board  50 . The circuit board  50  comprises an operational amplifier  51  and a comparator  52  connected to the operational amplifier  51 . A controlling signal generated by the microcontroller  40  is transmitted to illuminate the submitting pipes Q 100 -Q 107 . A collector of the Q 200  is connected to a power Vcc. An emitter of the Q 200  is connected to the ground via a first resistor R 1 . A positive terminal of the operational amplifier  51  is connected to the emitter of the Q 200 , and a negative terminal of the operational amplifier  51  is connected to ground via a second resistor R 2 . The second resistor R 2 , connected to a third resistor R 3  in series, is connected to an output terminal of the operational amplifier  51 . The output terminal of the operational amplifier  51  is connected to a negative terminal of the comparator  52 . A positive terminal of the comparator  52  is connected to a second power Vcc via the fourth resistor R 4 , and connected to the ground via a fifth resistor R 5 . An output terminal of the comparator  52  is connected to the microcontroller  40  via a sixth resistor R 6 . 
         [0013]    The operation principle of the detection system is that a controlling signal and a high level signal are generated by the microcontroller  40  to illuminate the submitting pipe Q 100 . The receiving pipes Q 200  receive the light from the submitting pipes Q 100  and generate a current I0. The current I0 flows through the first resistor R 1  and generates a voltage U0, U0=I0*R1. An output voltage U1 of the operational amplifier  51  is determined by the second resistor R 2  and the third resistor R 3 , U1=U0*(R2+R3)/R2. In one embodiment, a resistance value of the second resistor R 2  is 39 KΩ, and a resistance value of the third resistor R 3  is 10 KΩ. Therefore, the output voltage U1 of the operational amplifier  51  U1=U0*(39+10)/10=4.9*U0. The output terminal of the operational amplifier  51  is connected to the negative terminal of the comparator  52 . Thus, an input voltage of the negative terminal of the comparator  52  is equal to U1. The second power voltage U2 equals 5V. An input voltage U2 of the positive terminal of the comparator  52  is determined by the fourth resistor R 4  and the fifth resistor R 5 , that is, U3=U2*R5/(R4+R5). In one embodiment, a resistance value of the fourth resistor R 4  is 39 KSΩ, and a resistance value of the fifth resistor R 5  is 10 KΩ. Thus, U3=5*20/(10+20)=3.3V. An output voltage of the comparator  52  is determined by the U1 and the U3. When the U3&lt;U1, a low level voltage flows out of the output terminal of the comparator  52 . When the U3&gt;U1, a high level voltage flows out of the output terminal of the comparator  52 . The output voltage of the comparator  52  is transmitted to the microcontroller  40 , and the microcontroller  40  detects the output voltage of the comparator  52 . When the low level voltage flows out of the output terminal of the comparator  52 , the microcontroller  40  detects the light, which signifies that no object has dropped into the object passage  10 . When the high level voltage flows out of the output terminal of the comparator  52 , the microcontroller  40  can detect no light, which means that an object has dropped into the object passage  10 . 
         [0014]    Then, a controlling signal and a high level voltage are generated by the microcontroller  40  to illuminate the submitting pipe Q 101 , and an infrared rays is transmitted to the submitting pipes Q 100 -Q 102  via the submitting pipe Q 101 . If a high level voltage flows out of one of the receiving pipes Q 200 , Q 201 , the microcontroller  40  determines that light has been detected, and that an object has dropped into the object passage  10 . 
         [0015]    The microcontroller  40  repeats eight times and generates eight controlling signals, and the infrared rays are emitted in turn from each of the submitting pipes Q 100 -Q 107 . A time of emission of the infrared rays from each of the submitting pipes Q 100 -Q 107  can last 180 us. Therefore, the receiving pipes Q 200 -Q 201  receive the infrared rays emitted by the submitting pipe Q 100 . The receiving pipes Q 200 -Q 202  receive the infrared rays emitted by the submitting pipe Q 101 . The receiving pipes Q 201 -Q 203  receive the infrared rays emitted by the submitting pipe Q 102 . The receiving pipes Q 202 -Q 204  receive the infrared rays emitted by the submitting pipe Q 103 . The receiving pipes Q 203 -Q 205  receive the infrared rays emitted by the submitting pipe Q 104 . The receiving pipes Q 204 -Q 206  receive the infrared rays emitted by the submitting pipe Q 105 . The receiving pipes Q 205 -Q 207  receive the infrared rays emitted by the submitting pipe Q 106 . The receiving pipes Q 206 -Q 207  receive the infrared rays emitted by the submitting pipe Q 107 . 
         [0016]    In one embodiment, five objects or pieces in close proximity to each other drop. A thickness of each of the five pieces is 1 cm. The five pieces drop from a height of 1.2 m, and pass through the object passage  10  in 2 ms. In fact, a reaction time of each of the eight submitting pipes Q 100 -Q 107  is about 120 us. Each of the eight submitting pipes Q 100 -Q 107  can emit light in 180 us, so the total of the eight submitting pipes Q 100 -Q 107  can emit light in 1.44 ms. Even if the five pieces miss the top seven receiving pipes Q 200 -Q 206  and reach to the eighth pipe Q 207 , 1.44 ms of time has passed. At this time, a shielding time for the five pieces is 1.56 ms (1.44+0.12=1.56). However, the five pieces pass through the object passage  10  in 2 ms. Therefore, the shielding time (1.56 ms) is less than the time (2 ms) that the five pieces are detectable, and the detection system can detect the objects and their state. 
         [0017]    It is to be understood, however, that even though numerous characteristics and advantages have been set forth in the foregoing description of embodiments, together with details of the structures and functions of the embodiments, the disclosure is illustrative only and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.