1. Technical Field
The present disclosure relates to detection systems, and particularly to a detection system for an object dropping.
2. Description of Related Art
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.
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.
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.”
The submitting plate 20 comprises a plurality of submitting pipes, such as eight submitting pipes Q100-Q107 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 Q200-Q207 corresponding to the eight submitting pipes Q100-Q107 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 Q200-Q207 is an optical coupler.
Each of the eight receiving pipes Q200-Q207 is connected to a circuit board 50. For example, the receiving pipe Q200 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 Q100-Q107. A collector of the Q200 is connected to a power Vcc. An emitter of the Q200 is connected to the ground via a first resistor R1. A positive terminal of the operational amplifier 51 is connected to the emitter of the Q200, and a negative terminal of the operational amplifier 51 is connected to ground via a second resistor R2. The second resistor R2, connected to a third resistor R3 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 R4, and connected to the ground via a fifth resistor R5. An output terminal of the comparator 52 is connected to the microcontroller 40 via a sixth resistor R6.
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 Q100. The receiving pipes Q200 receive the light from the submitting pipes Q100 and generate a current I0. The current I0 flows through the first resistor R1 and generates a voltage U0, U0=I0*R1. An output voltage U1 of the operational amplifier 51 is determined by the second resistor R2 and the third resistor R3, U1=U0*(R2+R3)/R2. In one embodiment, a resistance value of the second resistor R2 is 39 KΩ, and a resistance value of the third resistor R3 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 R4 and the fifth resistor R5, that is, U3=U2*R5/(R4+R5). In one embodiment, a resistance value of the fourth resistor R4 is 39 KSΩ, and a resistance value of the fifth resistor R5 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<U1, a low level voltage flows out of the output terminal of the comparator 52. When the U3>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.
Then, a controlling signal and a high level voltage are generated by the microcontroller 40 to illuminate the submitting pipe Q101, and an infrared rays is transmitted to the submitting pipes Q100-Q102 via the submitting pipe Q101. If a high level voltage flows out of one of the receiving pipes Q200, Q201, the microcontroller 40 determines that light has been detected, and that an object has dropped into the object passage 10.
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 Q100-Q107. A time of emission of the infrared rays from each of the submitting pipes Q100-Q107 can last 180 us. Therefore, the receiving pipes Q200-Q201 receive the infrared rays emitted by the submitting pipe Q100. The receiving pipes Q200-Q202 receive the infrared rays emitted by the submitting pipe Q101. The receiving pipes Q201-Q203 receive the infrared rays emitted by the submitting pipe Q102. The receiving pipes Q202-Q204 receive the infrared rays emitted by the submitting pipe Q103. The receiving pipes Q203-Q205 receive the infrared rays emitted by the submitting pipe Q104. The receiving pipes Q204-Q206 receive the infrared rays emitted by the submitting pipe Q105. The receiving pipes Q205-Q207 receive the infrared rays emitted by the submitting pipe Q106. The receiving pipes Q206-Q207 receive the infrared rays emitted by the submitting pipe Q107.
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 Q100-Q107 is about 120 us. Each of the eight submitting pipes Q100-Q107 can emit light in 180 us, so the total of the eight submitting pipes Q100-Q107 can emit light in 1.44 ms. Even if the five pieces miss the top seven receiving pipes Q200-Q206 and reach to the eighth pipe Q207, 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.
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.
Number | Date | Country | Kind |
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2013100267395 | Jan 2013 | CN | national |