Please select the most similar patent number from A, B, C and D. Which number is?
An anti-theft alarm device for a safe comprises a main control chip (1), an alarm monitoring circuit (2), a vibration sensing device (3), a signal receiving device (4), and a signal transmitting device (5). The alarm monitoring circuit (2), the vibration sensing device (3), the signal receiving device (4), and the signal transmitting device (5) are all connected with the main control chip (1). The present invention has high degree of intellectualization and reliable safety performance.
A: Provided is a device for monitoring states of a door and a window. The device comprises a housing (3) provided with a groove (2). A signal sensing mechanism in the housing (3) comprises a first fixed sensing sheet (4) and a second fixed sensing sheet (9). The upper end and the lower end of an elastic connection member (7) in the groove (2) are respectively fixed on a first movable sensing sheet (6) and the second fixed sensing sheet (9). An insulation connection rod (1) is mounted on the first movable sensing sheet (6). The upper part of the connection rod (1) protrudes over the first fixed sensing sheet (4). A movable sensing sheet (8) is mounted on the lower end of the connection rod (1). A distance between the second movable sensing sheet (8) and the second fixed sensing sheet (9) is equal to a distance formed when the upper part of the connection rod (1) protrudes over the first fixed sensing sheet (4). The first fixed sensing sheet (4), the second fixed sensing sheet (9), the first movable sensing sheet (6) and the second movable sensing sheet (8) are all connected to a signal receiver (10). The device has a simple structure, can be used for monitoring a door and window system having higher air tightness and temperature keeping performance, can implement the monitoring in real time, and can improve the safety of a door and a window in use.
B: A P2P network based anti-theft system for a safe comprises a safe body (1), a monitoring device (2), a control device (3), a communication device (4), a server (5), and a client (6). The monitoring device (2), the control device (3), and the communication device (4) are all mounted on the safe body. The monitoring device (2) and the communication device (4) are both connected with the control device (3). The communication device (4), the server (5), and the client (6) are communicationally connected over a P2P network. The anti-theft system for a safe has a good information transmission effect and a low requirement for the server.
C: A downhole detector, comprising: a waterproof housing (1), a top portion of the waterproof housing (1) being provided with a lifting ring, while the waterproof housing (1) is provided therein with a circuit cavity (3) and a battery cavity (4); the battery cavity (4) is provided therein with a power supply battery, which is used for supplying power to a detector, and the circuit cavity is provided therein with a monitoring circuit; the monitoring circuit comprises a main control chip and a communication device, which is in signal connection with the main control chip, the communication device comprising a communication chip and an antenna; an oxygen concentration detector (5) is provided on the waterproof housing (1), the oxygen concentration detector (5) being in signal connection with the main control chip; by means of a simple structural design, when a downhole situation requires detection, the detector is lowered into a downhole by using only a rope and may carry out detection.
D: Provided is a downhole detector, comprising a waterproof outer housing (1); the top of said waterproof outer housing (1) is provided with a suspension ring (2), the waterproof outer housing (1) is internally provided with a circuit chamber (3) and a battery chamber (4), and said battery chamber (4) is internally provided with a power supply battery used for supplying power to the detector; the circuit chamber is internally provided with a monitoring circuit, said monitoring circuit comprising a main control chip and a communications device signally connected to said main control chip; said communications device comprises a communications chip and an antenna; the waterproof outer housing (1) is provided with an oxygen-concentration measurement device (5), said oxygen-concentration measurement device (5) being signally connected to the main control chip; by means of a simple structural design, it is possible to place the detector into a well using only a cord and perform detection when it is necessary to do so in a downhole setting.
Answer: B