Abstract:
A scanning device for scanning a barcode with plurality of bars of different degrees of grayscale includes a processing unit and a plurality of scanning units connected to the processing unit. Each scanning unit includes a light emitting unit and a light sensing unit. When each light emitting unit emits light, each light sensing unit detects reflected light from the barcodes and generates an electrical signal according to the intensity of the reflected light. The processing unit generates a code according to each electrical signal. All the generated codes comprise at least three different codes.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to a barcode, a scanning device for scanning the barcode, and a scanning system. 
         [0003]    2. Description of Related Art 
         [0004]    Barcodes provide fast and convenient identification of items, such as goods in supermarkets. A typical barcode includes a series of adjacent black bars and white bars (spaces) with variable widths between them. The barcodes can record binary information, for example, a thick white or black bar represents code “1”, and a thin white or black bar represents code “0”. However, the codes that can be represented by the bars of the barcode are limited. 
         [0005]    The scanning device for reading the barcodes includes a light source, a lens, a scanning module, and an analog to digital converter (ADC). When the scanning device scans a barcode, the scanning module receives light reflected by the barcode via the lens; the scanning module converts the reflected light into analog voltages and transmits the analog voltages to the ADC. The ADC converts the analog voltages to digital signals, and a computer connected to the scanning device analyzes the barcode according to the digital signals. However, the lens must be disposed in the scanning device, resulting in a bulky and complex scanning device. 
         [0006]    Therefore, there is room for improvement in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the embodiments can be better understood with references 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 four views. 
           [0008]      FIG. 1  is a schematic diagram of a barcode in accordance with one embodiment. 
           [0009]      FIG. 2  is a block diagram showing a scanning device in accordance with one embodiment. 
           [0010]      FIG. 3  is a circuit diagram of the scanning device shown in  FIG. 2  in accordance with one embodiment. 
           [0011]      FIG. 4  is a schematic diagram of the scanning device shown in  FIG. 2  scanning the barcode. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to  FIGS. 1 and 2 , a scanning system  99  (see in  FIG. 4 ) includes a barcode  100  and a scanning device  200  for scanning the barcode  100 . The barcode  100  includes ten bars S 0 , S 1  . . . S 9  disposed adjacent to each other. The width of each bar S 0 , S 1  . . . S 9  is the same. In this embodiment, the bars S 0 , S 1  . . . S 9  have the same basic property, but the values of that basic property of the bars S 0 , S 1  . . . S 9  are different in each bar. Each different bar represents a different code. 
         [0013]    In the embodiment, the basic property is grayscale. Each of the bars S 0 , S 1  . . . S 9  has a different degree of grayscale. The grayscales of the bars S 0 , S 1  . . . S 9  are described as follows: the bar S 0  is high white; the bar S 1  is gray consisting of 10% blackness and 90% whiteness, the bar S 2  is gray consisting of 20% blackness and 80% whiteness, the bar S 3  is gray consisting of 30% blackness and 70% whiteness, the bar S 4  is gray consisting of 40% blackness and 60% whiteness, the bar S 5  is gray consisting of 50% blackness and 50% whiteness, the bar S 6  is gray consisting of 60% blackness and 40% whiteness, the bar S 7  is gray consisting of 70% blackness and 30% whiteness, the bar S 8  is gray consisting of 80% blackness and 20% whiteness, the bar S 9  is gray consisting of 90% blackness and 10% whiteness. The bars grayscale should be changeable to represent different codes, for example, the bar S 0  may represent “9” and the bar S 9  may represent “5” (see the next paragraph), they cannot be permanent. In other embodiments, the grayscales of the bars S 0 , S 1  . . . S 9  may be changed according to need, for example, high white and deep black, the grayscales of each of the bars S 0 , S 1  . . . S 9  also can be changed to polychromatic colors, such as red, or blue, or other color. 
         [0014]    In the embodiment, the codes represented by the bars S 0 , S 1  . . . S 9  are described as follows: the bar S 0  represents number “0”, the bar S 1  represents number “1”, the bar S 2  represents number “2”, the bar S 3  represents number “3”, the bar S 4  represents number “4”, the bar S 5  represents number “5”, the bar S 6  represents number “6”, the bar S 7  represents number “7”, the bar S 8  represents number “8”, and the bar S 9  represents number “9”. In other embodiments, the codes represented by the bars S 0 , S 1  . . . S 9  may be changed as needed. The bars S 0 , S 1  . . . S 9  can respectively represent the letters “A”, “B”, “C”, “D”, “E”, “F”, “G”, “H”, “I”, “J”. 
         [0015]    Referring to  FIG. 2 , the scanning device  200  includes a processing unit  20 , a power supply  21 , a switch unit  22  and a plurality of scanning units  23 . The power supply  21  is electrically connected to the processing unit  20  and the switch unit  22  for providing a supply voltage. The switch unit  22  is electrically connected to the processing unit  20 , and is further electrically connected between the power supply  21  and the scanning units  23 . The switch unit  22  allows the supply voltage from the power supply  21  to reach the processing unit  20  and the scanning units  23 . The scanning units  23  have a one-to-one relationship with the bars S 0 , S 1  . . . S 9 . Each scanning unit  23  is electrically connected between the processing unit  20  and the switch unit  22 . 
         [0016]    Referring to  FIG. 3 , the switch unit  22  includes a first transistor Q 1 , a second transistor Q 2 , a first resistor R 1 , a second resistor R 2 , a third resistor R 3  and a fourth resistor R 4 . A base of the first transistor Q 1  is electrically connected to the processing unit  20  via the first resistor R 1 , a collector of the first transistor Q 1  is electrically connected to a base of the second transistor Q 2  via the third resistor R 3 , and an emitter of the first transistor Q 1  is grounded. The base of the first transistor Q 1  is further grounded via the second resistor R 2 . The base of the second transistor Q 2  is connected to the power supply  21  via the fourth resistor R 4 , a collector of the second transistor Q 2  is connected to the scanning units  23 , and an emitter of the second transistor Q 2  is connected to the power supply  21 . In the embodiment, the first transistor Q 1  is a NPN type bipolar junction transistor, and the second transistor Q 2  is a PNP type bipolar junction transistor. 
         [0017]    Each scanning unit  23  is aligned with a single bar of the bars S 0 , S 1  . . . S 9 , and includes a light emitting unit  231  and a light sensing unit  232 . The width of each scanning unit  23  is not greater than the width of the bars S 0 , S 1  . . . S 9 . In the embodiment, the light emitting unit  231  includes a light emitting diode D 1 , and the light sensing unit  232  includes a photodiode D 2 . 
         [0018]    The anode of each light emitting diode D 1  is connected to the collector of the transistor Q 2 , and the cathode of each light emitting diode D 1  is grounded. The anode of each photodiode D 2  is connected to the processing unit  20 , and the cathode of each photodiode D 2  is grounded. 
         [0019]    The principle of operation of the power manager circuit  10  is illustrated as follows: 
         [0020]    Referring to  FIG. 4 , when the switch unit  22  establishes an electrical connection between the power supply  21  and the scanning units  23  in response to the signal from the processing unit  20 , each light emitting unit  231  emits light simultaneously. Each light sensing unit  232  detects light reflected from the bars S 0 , S 1  . . . S 9  and generates an electrical signal according to the intensity of the reflected light. The processing unit  20  converts the electrical signal from each light sensing unit  323  into one code. In the embodiment, the codes of the bars S 0 , S 1  . . . S 9  respectively represent numbers “0”, “1”, “2”, “3”, “4”, “5”, “6”, “7”, “9”. 
         [0021]    Although information and the advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the present 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 present embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.