Please select the most similar patent number from A, B, C and D. Which number is?
An intra-plot seed printer self-checking system, which relates to the technical field of seeding, and is used for detecting the flatness of soil. The system comprises: a rack, wherein supporting legs are arranged at the bottom part of the rack, and rollers are arranged at the bottom part of the supporting legs; and a detection unit, which comprises a guide pipe and infrared emitters that are fixed to the two adjacent side walls of the rack, and water and floating balls that are arranged in the guide pipe, the guide pipe being a &#34;]&#34;-shaped structure that has upward-facing opening. When the rack is in a horizontal state, the floating balls are arranged in vertical parts at two ends of the guide pipe under the buoyant action of the water; infrared receivers are arranged at two ends of the side walls of the rack on which the infrared emitters are mounted; the two infrared receivers and the infrared emitters are located on the same straight line; and a shading belt that blocks the linear propagation of infrared rays is arranged in the middle of the floating balls. According to the present invention, the inclination state of the rack may be detected, and seeding precision is thus guaranteed.
A: An intelligent seed tape braiding machine, used for adjusting the distance between seeds on a seed tape according to the ground flatness in the sowing process. The intelligent seed tape braiding machine comprises in order along the direction of movement: a winding disc on which the seed tape is wound; a carrier roller, a circular groove being formed in the outer wall of the carrier roller; a support table, the upper surface of the support table being in contact with the seed tape, a recess being formed in the upper surface of the support table, the support table being provided with a stapler mounting recess communicated with the recess, and a collection cavity being formed in the lower portion of the support table; a pressure rod movably arranged on the support table and being of a &#34;7&#34;-shaped structure, a lifting mechanism being provided between the vertical part of the pressure rod and the support table, and the horizontal part of the pressure rod being disposed above the recess; a cutting and connecting unit used for cutting and then connecting the seed tape; and a compaction unit comprising a pair of pressure rollers arranged up and down. According to the present invention, the distance between two seeds on a certain section of the seed tape is adjusted by cutting and reconnecting the seed tape, so as to ensure the uniformity of the sowing distance.
B: Disclosed are a GPRS technology-based stage performer safety assurance system and method, specifically relating to the technical field of stage safety monitoring. The safety assurance system comprises a lifting stage; fixing blocks are fixedly provided at four corners of the top end of the lifting stage; a first infrared emitter and a first infrared receiver are respectively embedded in two adjacent surfaces of the outer end of each fixing block; a hollow-square-shaped recess is formed in the top end of the lifting stage; a rectangular frame is provided inside the hollow-square-shaped recess; an electric push rod is fixedly provided at the bottom end of the interior of the hollow-square-shaped recess; a groove is formed in the top end of the lifting stage; a protection assembly is provided inside the groove; and a positioning assembly is placed at the top end of the lifting stage. According to the present invention, the rectangular frame extends out of the top end of the lifting stage to surround the outer sides of the feet of performers to protect the performers, the two feet of each performer are fixed by means of tight elastic straps, the protection safety is improved, the performers are reminded to be in a safe area all the time by means of the positioning assembly, and the safety assurance performance is further improved.
C: Disclosed is an infrared-sensing splash-proof umbrella with a deformable umbrella cover, wherein a battery (5) is in circuit connection with a central processor (6), the central processor (6) is in circuit connection with a wireless receiver (7), a distal end of each of umbrella ribs (3) is connected to an infrared sensor (8) for sensing a passer-by in the near distance, a wireless transmitter (9) is connected to the infrared sensor (8), the infrared sensor (8) is arranged corresponding to a telescopic rod assembly (4); and the infrared sensor (8) is in signal connection with the wireless receiver (7) of the central processor (6) by means of the wireless transmitter (9). By arranging a plurality of infrared sensors (8) on end parts of the umbrella ribs (3), it can be detected whether a passer-by is in the vicinity, and if it is detected that there is a passer-by, the umbrella cover is held up, so as to reduce rainwater trickled down from the umbrella cover splashing the person in the vicinity, while preventing the person holding the umbrella from being wetted by rain.
D: The present invention relates to a metal hair dryer with an adjustable air volume. The hair dryer comprises: an air-blocking plate that is arranged at an air inlet of the hair dryer, is of a circular structure and is used for adjusting the air intake volume of the hair dryer; a field data extraction device comprising an infrared transmitter, an infrared receiver, an ARM11 processor and an extraction controller, wherein the infrared transmitter is located on a data collection device and is used for vertically transmitting an infrared signal downwards, and the infrared receiver is located beside the infrared transmitter and is used for receiving the infrared signal, which is reflected back; and an air-blocking plate driving device, which is respectively connected to a human body detection device and the air-blocking plate and is used for enabling an operation on the air-blocking plate when the human body detection device determines that there is a human body. By means of the present invention, an effective authentication mechanism is introduced for the hair dryer.
Answer: A