A tire pressure sensor for mining trucks

Abstract

The present invention provides a tire pressure sensor for a mining truck, comprising: a shell, an antenna is arranged on the shell, a battery and a circuit board are arranged in the shell, a central processing unit, a temperature sensor, an integration circuit and a wireless module are arranged on the circuit board; the central processing unit has a plurality of IO ports, one of the IO ports is used as a mode control IO port, and the other IO ports are used as serial communication IO ports, the serial communication IO port is connected to the corresponding serial communication port on the wireless module through a wire and a current limiting resistor respectively, the mode control IO port is connected to the mode switching port on the wireless module through a wire, the mode control IO port is also connected to the signal transceiver port of the temperature sensor through a wire, the integration circuit is connected between the mode control IO port and the mode switching port of the wireless module, wherein the temperature sensor is a short pulse communication mode module, and the wireless module is a long level communication mode module.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle tire pressure monitoring, and in particular relates to a tire pressure sensor for a mining truck. Background Art

[0002] The tire pressure sensor of a mining truck detects the tire pressure inside the tire. The sensor requires the temperature measurement accuracy to be within 1°C. Therefore, the built-in temperature measurement function of the traditional tire pressure sensor cannot meet the requirements, and the temperature sensing must be expanded externally. The tire pressure sensor is installed inside the tire. If the tire pressure sensor circuit is complex, its volume and overall power consumption will increase, which will shorten the battery life, reduce product reliability, and increase the replacement frequency of the tire pressure sensor. The tire size of a mining truck is huge, reaching 3.7 meters in diameter. The workload of each tire removal is very large, and the labor cost is very high. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a tire pressure sensor for a mining truck, which is used to overcome the above problems or at least partially solve or alleviate the above problems.

[0004] The present invention proposes a tire pressure sensor for a mining truck, characterized in that it includes: a shell, an antenna is arranged on the shell, a battery and a circuit board are arranged in the shell, a central processing unit, a temperature sensor, an integration circuit and a wireless module are arranged on the circuit board; the central processing unit has multiple IO ports, one of which is used as a mode control IO port, and the other multiple IO ports are used as serial communication IO ports, the serial communication IO port is connected to the corresponding serial communication port on the wireless module through a wire and a current limiting resistor respectively, the mode control IO port is connected to the mode switching port on the wireless module through a wire, the mode control IO port is also connected to the signal transceiver port of the temperature sensor through a wire, the integration circuit is connected between the mode control IO port and the mode switching port of the wireless module, wherein the temperature sensor is a short pulse communication mode module, and the wireless module is a long level communication mode module.

[0005] The present invention also has the following optional features.

[0006] Optionally, the integration circuit includes a current limiting resistor connected in series between the mode control IO port and the mode control port on the wireless module, and a capacitor externally connected between the mode control port on the wireless module and the positive electrode of the circuit.

[0007] Optionally, the central processing unit is an SP370 chip.

[0008] Optionally, the wireless module is an AS32-TTL-100 module.

[0009] Optionally, the temperature sensor is a DS18b20 temperature sensor.

[0010] Optionally, a pull-up circuit is externally connected to the wire between the mode control IO port and the signal transceiver port of the temperature sensor to provide a pull-up current for the temperature sensor.

[0011] Optionally, the shell is a metal shell and is an integrated structure with the antenna.

[0012] Beneficial effects of the present invention:

[0013] The tire pressure sensor for mining trucks of the present invention is connected to the signal transceiver port of the temperature sensor and the mode switching port of the wireless module through an IO port of the central processor at the same time, and an integration circuit is connected at the mode switching port of the wireless module. According to the difference in communication pulse widths of the temperature sensor and the mode switching port of the wireless module, the mode switching port of the wireless module can filter out the communication signal between the central processor and the temperature sensor through the integration circuit, and the temperature sensor can automatically filter out the signal of the central processor controlling the wireless module, thereby realizing the function of one IO port controlling multiple external devices, so that the central processor and the temperature sensor are integrated in the sensor circuit, and the microcontroller unit on the central processor chip can control the temperature sensor, without the need for an external expansion chip, thereby reducing the system volume and overall power consumption, extending the battery life, improving the product reliability, reducing the replacement frequency of the tire pressure sensor, and greatly saving manpower. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the circuit board structure of the tire pressure sensor for mining trucks of the present invention;

[0015] Figure 2 The invention discloses a circuit connection diagram of a tire pressure sensor for a mining truck.

[0016] In the above picture:

[0017] 1 housing; 2 battery; 3 circuit board; U1 central processing unit; U2 temperature sensor.

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments; DETAILED DESCRIPTION

[0019] refer to Figure 1 and Figure 2, an embodiment of the present invention proposes a tire pressure sensor for a mining truck, comprising: a shell 1, an antenna is arranged on the shell 1, a battery 2 and a circuit board 3 are arranged in the shell 1, a central processing unit U1, a temperature sensor U2, an integration circuit and a wireless module are arranged on the circuit board 3; the central processing unit 4 has a plurality of IO ports, one of which is used as a mode control IO port, and the other plurality of IO ports are used as serial communication IO ports, the serial communication IO port is connected to the corresponding serial communication port on the wireless module through a wire and a current limiting resistor respectively, the mode control IO port is connected to the mode switching port on the wireless module through a wire, the mode control IO port is also connected to the signal transceiver port of the temperature sensor U2 through a wire, the integration circuit is connected between the mode control IO port and the mode switching port of the wireless module, wherein the temperature sensor U2 is a short pulse communication mode module, and the wireless module is a long level communication mode module.

[0020] refer to Figure 1 and Figure 2 The shell 1 is fixed in the tire of the mining truck. The battery 2 and the circuit board 3 are assembled in the shell 1 and then fixed by glue. The circuit board 3 is provided with an integrated circuit including a central processing unit U1, a temperature sensor U2, an integration circuit and a wireless module; wherein, a plurality of IO ports of the central processing unit U1 are used as serial communication ports to send and receive signals with the serial communication port of the wireless module U3, and the remaining IO port of the central processing unit U1 is used as a mode control port and is connected to the signal receiving and sending port of the temperature sensor U2 and the mode switching port of the wireless module U3 at the same time. The pulse width required for the communication signal of the temperature sensor U2 should be much smaller than the level communication width required for the mode switching signal of the wireless module U3. When the mode control IO port of the central processing unit U1 is connected to the When the temperature sensor U2 communicates via short pulses, the integration circuit can filter out the short pulses before the mode switching port of the wireless module, so that the mode switching port of the wireless module U3 is not interfered with; when the mode control IO port of the central processor U1 sends a long pulse to the switching port of the wireless module U3 for wireless transceiver mode switching, the pulse width does not conform to the communication timing of the temperature sensor U2 and will be automatically filtered out, and the temperature sensor U2 will not be affected; one IO port of the central processor U2 can control the temperature sensor U2 to switch the signal transceiver mode of the temperature acquisition wireless module, which can save one pin, reduce the requirement for the number of IO ports of the central processor U1, avoid the use of external expansion chips and cause the system volume to increase, and reduce costs at the same time.

[0021] refer to Figure 2According to an embodiment of the present invention, the integration circuit includes a current limiting resistor RP1 connected in series between the mode control IO port and the mode control port on the wireless module U3, and a capacitor C2 externally connected between the mode control port on the wireless module U3 and the positive electrode VCC of the circuit.

[0022] The current limiting resistor RP1 is 10k ohms and the capacitor C2 is 1uF.

[0023] refer to Figure 1 According to one embodiment of the present invention, the central processor U1 is a SP370 chip.

[0024] SP370 provides three IO ports, namely PP0, PP1 and PP2. PP1 and PP2 are occupied as serial communication IO ports. PP0 needs to control the transceiver mode of the wireless module U3 and read the temperature information of the temperature sensor U2.

[0025] refer to Figure 2 According to one embodiment of the present invention, the wireless module U3 is an AS32-TTL-100 module.

[0026] The RXD and TXD of the wireless module AS32-TTL-100 are connected to the PP1 and PP2 of the SP370 respectively, the MD1 of the wireless module AS32-TTL-100 is connected to the PP0 of the SP370, and the transceiver mode control of the wireless module AS32-TTL-100 is effective at low level with a width of 400mS.

[0027] refer to Figure 1 and Figure 2 According to one embodiment of the present invention, the temperature sensor U2 is a DS18b20 temperature sensor.

[0028] The DS18B20 communication timing operates mainly with short pulses, and the communication is at a high level at the end. The maximum low-level time for DS18B20 communication reset is 960uS, and the maximum low-level time for normal single-bit communication is 60uS. According to the 16-bit temperature reading, the total low-level time length is 60uS*16=960uS, and the maximum low-level time length of U2 reset and communication is 960uS, which is much smaller than the 400mS low-level width controlled by the transceiver mode of the wireless module AS32-TTL-100. Therefore, DS18B20 will not be affected by the signal of SP370 controlling the transceiver mode of AS32-TTL-100, and will be filtered out by the integration circuit before MD1 of the wireless module AS32-TTL-100.

[0029] refer to Figure 2According to an embodiment of the present invention, a pull-up resistor R1 is externally connected to the wire between the mode control IO port PP0 and the signal transceiver port of the temperature sensor U2, and the other end of the pull-up resistor R1 is connected to the positive electrode VCC of the circuit to provide a pull-up current for the temperature sensor U2. An isolation resistor R3 is also connected to the wire between the signal transceiver port of the temperature sensor U2 and the access point of the pull-up resistor R1.

[0030] The temperature sensor U2 uses a DS18B20 temperature sensor, and its signal transceiver port is a single-line communication. It is a high-resistance input when receiving and an open-drain output when sending. That is, when the output is 0, it is pulled down to a low level through a transistor, and when it is output 1, it is high resistance and needs an external pull-up resistor R1 to pull it to a high level, otherwise it cannot output 1. Among them, the isolation R3 is 510 ohms, and the pull-up resistor R1 is 51k ohms.

[0031] refer to Figure 2 Specifically, the core function of the system is the CPU unit 101, U1 SP370 completes the wireless module U3 transceiver mode control and reads the temperature information of the temperature sensor module U2 through PP0. The wireless module U3 transceiver mode control is low level effective, with a width of 400mS; the temperature sensor module U2 communicates according to the DS18B20 bus communication timing. The two cannot affect each other.

[0032] refer to Figure 2 , the working principle and working process of the present invention are described in detail below.

[0033] When SP370 controls the wireless module AS32-TTL-100, because the wireless module AS32-TTL-100 transceiver mode controls the low level to be effective, the width is 400mS, and this pulse width is 400mS. For DS18B20, it does not conform to the DS18B20 bus communication timing and will be automatically filtered out. Under normal circumstances, DS18B20 has no effect, but in order to prevent unexpected transient error responses of DS18B20, the system adds a protective resistor R3, 510 ohms, to prevent SP370 and DS18B20 level conflicts. When SP370 controls the wireless module AS32-TTL-100 and provides a low level with a width of 400mS, whether DS18B20 responds or not, it will not affect the low level output with a width of 400mS.

[0034] When SP370 controls DS18b20, port PP0 operates DS18b20 through isolation resistor R3. PP0 operates according to the DS18B20 communication timing, mainly with short pulses. It is high level when the communication ends. The maximum low level time of communication reset is 960uS, and the maximum low level time of normal single-bit communication is 60uS. According to the 16-bit temperature reading, the total low level time length is 60uS*16=960uS, and the maximum low level time length of DS18b20 reset and communication is 960uS. This low level time should ensure that the control signal S2 output by PP0 to the wireless module AS32-TTL-100 through RP1 is high level. For this reason, the system adopts an integration circuit composed of RP1 and C2 to ensure that S2 is high level. Considering the low power consumption factor, R1 takes 51k ohms, RP1 takes 10k ohms, considering the time constant factor, C2 takes 105, that is, 1uF, and the time constant τ=10k*1uF=10mS, which is about 0.1τ relative to 960uS. Under the low-level discharge time of 960uS, the VCC voltage drops to 0.9 times of the original. For the AS32-TTL-100 module, S2 is always considered to be a high level and will not be affected by the low level of PP0 of SP370 and DS18B20 communication.

[0035] After actual verification, the communication between the tire pressure sensor chip SP370 and the temperature sensor module DS18B20 module and the wireless module AS32-TTL-100 is stable and reliable. Only one PP0 pin is used to control the two external devices, the temperature sensor DS18B20 module and the wireless module AS32-TTL-100, which provides a strong technical guarantee for the miniaturized design of the tire temperature and pressure monitoring system. The core unit IO control unit 102 is completed with only a few simple components such as resistors and capacitors. Compared with the traditional external expansion serial and parallel latch chips and the configuration of relevant registers inside the CPU, it is more feasible, reducing the volume while also saving project costs.

[0036] refer to Figure 1 According to an embodiment of the present invention, the housing 1 is a metal housing, which is an integrated structure with the antenna. The metal housing is connected to the signal transmission circuit of the wireless module AS32-TTL-100 and can be directly used as an antenna.

[0037] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The components and structures not described in detail in this embodiment are well-known components and common structures or common means in the industry, and are not described here one by one.

Claims

1. A tire pressure sensor for a mining truck, characterized in that: include: A shell (1), wherein an antenna is arranged on the shell (1), a battery (2) and a circuit board (3) are arranged inside the shell (1), and a central processing unit (U1), a temperature sensor (U2), an integration circuit and a wireless module are arranged on the circuit board (3); the central processing unit (U1) has a plurality of IO ports, wherein one IO port is used as a mode control IO port, and the other plurality of IO ports are used as serial communication IO ports, the serial communication IO ports are connected to the corresponding serial communication ports on the wireless module via wires and current limiting resistors, the mode control IO port is connected to the mode switching port on the wireless module via wires, the mode control IO port is also connected to the signal transceiver port of the temperature sensor (U2) via wires, and the integration circuit is connected between the mode control IO port and the mode switching port of the wireless module, wherein the temperature sensor (U2) is a short pulse communication mode module, and the wireless module is a long level communication mode module; The integration circuit includes a current limiting resistor connected in series between the mode control IO port and the mode control port on the wireless module, and a capacitor externally connected between the mode control port on the wireless module and the positive electrode of the circuit.

2. The tire pressure sensor for mining trucks according to claim 1, characterized in that: The central processing unit (U1) is a SP370 chip.

3. The tire pressure sensor for mining trucks according to claim 1, characterized in that: The wireless module is an AS32-TTL-100 module.

4. The tire pressure sensor for mining trucks according to claim 2, characterized in that: The temperature sensor (U2) is a DS18b20 temperature sensor.

5. The tire pressure sensor for mining trucks according to claim 4, characterized in that: A pull-up resistor is externally connected to the wire between the mode control IO port and the signal receiving and transmitting port of the temperature sensor (U2) to provide a pull-up current for the temperature sensor (U2).

6. The tire pressure sensor for mining trucks according to claim 1, characterized in that: The shell (1) is a metal shell and is an integrated structure with the antenna.

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