Air conditioner data acquisition and remote uploading device

Abstract

The utility model discloses an air conditioner data acquisition and remote uploading device which is applied to an air conditioner data communication system. The device is integrated with an OpenCPU architecture, comprises a main control chip U2A and an NBModule module U2B, cooperatively realizes data acquisition, protocol analysis and wireless communication, and feeds back networking, fault and upgrading states in real time through a double-color LED; the power supply management circuit adopts the combination of DC-DC and LDO, supports 10V-20V wide voltage input, and outputs stable 3.6 V power supply; the UART level conversion circuit realizes 5V and 3.6 V bidirectional level matching through an MOS tube and a triode, so that the communication compatibility is guaranteed; the SIM card circuit integrates TVS protection and an adaptive power supply, and supports a multi-voltage SIM card; a hardware and software watchdog dual-monitoring mechanism prevents system deadlock. According to the scheme, the problems that hardware is complex, data processing and transmission integrity is not high, and reliability and intellectualization are remarkably insufficient in the prior art are solved, and the system has the advantages of low power consumption, high reliability, low cost and easy maintenance.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning control and communication technology, specifically to an air conditioning data acquisition and remote uploading device. Background Technology

[0002] With the continuous development of IoT technology, the number of IoT smart devices is growing exponentially, giving rise to remote data monitoring systems that combine air conditioning equipment data with IoT technology. Traditional remote data acquisition and uploading technologies for air conditioning equipment mainly rely on communication methods such as Wi-Fi, LoRa, and 4G / 5G. In recent years, NB-IoT (Narrowband Internet of Things) technology has gradually emerged due to its low power consumption, wide coverage, massive connectivity, and low cost. It utilizes existing cellular network infrastructure and can achieve remote data transmission without additional gateways, making it particularly suitable for remote areas or areas where cabling is difficult.

[0003] Currently, common methods for air conditioner data acquisition and remote uploading include: connecting the air conditioner via Wi-Fi or Bluetooth to upload data to a local router or gateway, and then transmitting it to the cloud via the internet; LoRa + concentrator mode: the LoRa module collects air conditioner data and sends it to the nearest concentrator via LoRa wireless signal, and the concentrator then transmits this data to the air conditioner manufacturer's central monitoring system via wired or wireless network; directly connecting to the public network via 4G / 5G module to achieve direct data transmission to the cloud; and adopting a discrete architecture of "NB-IoT module + external microcontroller," where the microcontroller is responsible for protocol parsing, data caching, and communication control, while the NB-IoT module is only responsible for basic communication functions.

[0004] Despite the advantages of each of the aforementioned technologies, they still have significant shortcomings in terms of the integrity, reliability, and intelligence of data processing and transmission: Wi-Fi or Bluetooth modes require the deployment of Wi-Fi networks, making them unusable in remote areas or areas without network coverage, and the continuous operation of the module increases the energy consumption of air conditioning equipment; LoRa + concentrator mode requires the additional deployment of a concentrator, increasing wiring and maintenance costs, and LoRa has weak penetration capabilities, making the signal prone to attenuation in environments with multiple obstacles (such as high-rise buildings); 4G / 5G mode modules have high unit prices, and data traffic costs are continuously consumed, and maintaining a continuous 4G connection increases the energy consumption of the device; the microcontroller + NB-IoT module mode has high hardware complexity, a long development cycle for dual-chip collaborative development, high development costs, firmware upgrades require full OTA, upgrades consume NB-IoT bandwidth resources, and maintenance is difficult.

[0005] Chinese patent document CN213421397U discloses a "4G shared air conditioner control module based on an OpenCPU solution," which includes a 4G module and a Bluetooth module. The 4G module and Bluetooth module are connected to the air conditioner base plate. The 4G module is connected to an e-SIM card / card slot, a 4G antenna interface, a USB interface, and indicator lights. The use of OpenCPU effectively reduces the overall cost of the device and improves the security of data interaction. The low latency of 4G communication significantly enhances the user experience. Furthermore, Bluetooth data channels are enabled in areas with poor network coverage. However, this technical solution still requires collaboration between an OpenCPU solution and external microcontrollers such as an external 4G module and Bluetooth module, resulting in high hardware complexity and high development and maintenance costs. Summary of the Invention

[0006] This utility model aims to provide an air conditioning data acquisition and remote upload device for use in air conditioning data communication systems. Through a hardware integrated architecture and a multi-level transmission reliability mechanism, it solves the problems of high hardware complexity, data loss due to network congestion, insecure firmware upgrades, and short storage life in traditional solutions. It achieves low power consumption, high reliability, easy maintenance, and high security in air conditioning data communication systems, thus filling the gaps in existing technologies.

[0007] Another objective of this invention is to integrate an OpenCPU architecture, including a main control chip U2A and an NB_Module U2B, to collaboratively achieve data acquisition, protocol parsing, and wireless communication. The power management circuit uses a combination of DC-DC and LDO, supporting a wide voltage input of 10V to 20V and a stable 3.6V output. The UART level conversion circuit uses MOSFETs and transistors to achieve bidirectional level matching between 5V and 3.6V, ensuring communication compatibility. The SIM card circuit integrates TVS protection and adaptive power supply, supporting multi-voltage SIM cards. A dual monitoring mechanism of hardware and software watchdogs monitors the system status in real time, preventing program deadlock, improving device reliability, and enhancing system stability.

[0008] The purpose of this invention is to adopt discrete network access, staggered reporting, and missed reporting compensation mechanisms in the device software, combined with the exponential backoff retransmission algorithm to improve data transmission reliability, and to provide real-time feedback on network, fault, and upgrade status through dual-color LEDs. This solves the problems of complex hardware, network congestion, and easy data loss in traditional technologies, and has the advantages of low power consumption, high reliability, and easy maintenance.

[0009] To achieve the above objectives, this utility model proposes an air conditioning data acquisition and remote upload device, applied to an air conditioning data communication system: It integrates an OpenCPU architecture, including an NB-IoT module circuit and a power management circuit, as well as a SIM card circuit and a hardware watchdog circuit; the NB-IoT module circuit is connected to the power management circuit and an LED indicator circuit, and also to the SIM card circuit and the hardware watchdog circuit; the power management circuit includes a DC-DC converter circuit and an LDO converter circuit, connected to the NB-IoT module circuit and a power input port, the power input port is also connected to a UART level conversion circuit, and the UART level conversion circuit is connected to the NB-IoT module circuit.

[0010] Preferably, the core components of the NB-IoT module circuit mainly include the main control chip U2A and the NB_Module U2B, as well as the external memory chip MX25; the NB_Module U2B is connected to the external memory chip MX25 through the SPI interface and is mainly responsible for the wireless communication of the module.

[0011] Preferably, the main control chip U2A connects the antenna interface to the UART level conversion circuit, the SIM card circuit to the hardware watchdog circuit, and also connects to the power management circuit and the external storage circuit. The antenna interface is connected to the antenna matching circuit through the RF_ANT pin of the main control chip U2A to optimize RF signal transmission. The antenna matching circuit consists of resistor R19 and capacitors C23 and C24, which perform low-pass filtering to suppress high-frequency noise. The UART level conversion circuit is connected to the main control chip U2A through the NB_TEST transceiver interface and the four pins of the NB transceiver interface. The SIM card circuit is connected to the main control chip U2A through the SIM interface. The hardware watchdog circuit is connected to the main control chip U2A through the NB_RST pin. The power management circuit converts the input voltage to 3.6V and then supplies power to the NB-IoT module circuit, SIM card, and LED, and is connected to the power pin of the main control chip U2A. The core component of the external storage circuit is the external memory chip MX25, which supports firmware storage and fast reading, and is connected to the main control chip U2A through the VDD_IO interface.

[0012] Preferably, the power management circuit provides a stable power supply for the NB-IoT module and peripheral circuits to prevent voltage fluctuations from damaging the device. It includes a DC-DC converter circuit and an LDO converter circuit. The DC-DC converter circuit is connected to the power input port, accepting a wide voltage range of 10V to 20V (DCIN). After conversion by the DC-DC converter, it outputs a 5V voltage, and its output terminal is connected to the input terminal of the LDO converter circuit. The LDO converter circuit mainly includes an LDO regulator chip U1, which is responsible for reducing the 5V voltage output by the DC-DC converter circuit to 3.6V. The output terminal of the LDO regulator chip U1 is connected to the power pin of the NB-IoT module circuit.

[0013] Preferably, the UART level conversion circuit is responsible for resolving the communication compatibility issue between the 5V power supply voltage of the main control chip U2A and the 3.6V power supply voltage of the NB_Module module U2B in the NB-IoT module circuit. It includes core components N-channel MOSFETs Q1 and Q2, and also includes NPN transistors Q3 and Q4: the drain D of MOSFET Q1 is connected to the 5V output of the DC-DC conversion circuit through resistor R3, the gate G is grounded, and the source S is connected to the NB_RX interface of the main control chip U2A in the NB-IoT module circuit; the drain D of MOSFET Q2 is connected to the 5V output of the DC-DC conversion circuit through resistor R4, the gate G is grounded, and the source S is connected to the NB_RX interface of the main control chip U2A in the NB-IoT module circuit. The S terminal of transistor Q3 is connected to the NB_TX interface of the NB-IOT module circuit main control chip U2A; the B terminal of transistor Q3 is connected to the VDD_IO pin of the low-voltage side NB-IOT module circuit main control chip U2A, the E terminal is connected to the NB_TEST_TX pin of the high-voltage side NB-IOT module circuit main control chip U2A, and the C terminal is connected to a fixed level of 5V through a current-limiting resistor R27; the B terminal of transistor Q4 is connected to a fixed level of 5V through a current-limiting resistor R28, the E terminal is connected to the low-voltage side signal line, and the C terminal is connected to the NB_TEST_RX pin of the high-voltage side NB-IOT module circuit main control chip U2A.

[0014] Preferably, the LED indicator circuit includes two dual-color LED indicators, green LED D6 and red LED D7, which are connected to the GPIO pins NB_LED1 and NB_LED2 of the NB-IoT module circuit main control chip U2A through current-limiting resistors R7 and R8, respectively. These different colors, along with constant illumination and flashing modes, convey multi-dimensional information and intuitively display the module's operating status. Green LED D6 indicates the device's network connection status, normal data transmission, or normal system operation; red LED D7 indicates an abnormal state. A constant green light indicates the device is online and idle; a slow flashing green light indicates data upload in progress; a fast flashing red light indicates an upgrade in progress; and a constant red light indicates a serious fault alarm.

[0015] Preferably, the SIM card circuit is connected to the main control chip U2A via four SIM pins, mainly including the SIM card socket J4 and the telecom MFF2 chip U3. The SIM card socket J4 is a NANO SIM card socket, supports hot-swapping, has 6 pins, and a surface-mount transient voltage suppressor diode D11 is connected in parallel between its VCC and GND pins, positioned close to the SIM card socket J4 to shorten the protection path. The input side of the telecom MFF2 chip U3 is connected to the four SIM pins of the NB-IoT module circuit main control chip U2A, and the output side is connected to the corresponding pins of the SIM card socket J4. It is decoupled by filter capacitors C5 to C8, mainly used to convert the 3.6V signal output by the main control chip U2A into a voltage supported by the SIM card to prevent overvoltage damage to the SIM card.

[0016] Preferably, the SIM pins include a SIM_DIO pin and a SIM_CLK pin, as well as a SIM_RST pin and a SIM_VDD pin: the SIM_DIO pin is directly connected to the IO pin of the SIM card slot J4 for transmitting APDU commands and responses; the SIM_CLK pin outputs a clock signal to the CLK pin of the SIM card slot J4, with a frequency range of 1-5MHz, to synchronize data transmission timing; the SIM_RST pin outputs a reset pulse to the RST pin of the SIM card slot J4 for initializing the SIM card or forcibly restarting; the SIM_VDD pin provides a 3.6V power supply to the VCC pin of the SIM card slot J4, supporting 1.8V, 3V, and 5V power supply auto-adaptation.

[0017] Preferably, the hardware watchdog circuit connected to the main control chip U2A is a timer circuit. The reset pin NB_RST is connected to the system reset terminal of the NB-IoT module circuit through a pull-up resistor R14. The program clears the timer within a certain time range to monitor the system's operating status. When the program is working normally, the timer does not overflow and does not generate a reset signal. If the program times out without responding, it triggers a reset and restarts the system to prevent program deadlock. The hardware watchdog circuit starts immediately when the system is powered on, operates independently of the system's main processor, is not affected by software faults, and cannot be disabled or bypassed by software, ensuring that the monitoring mechanism is always effective. The NB_Module U2B has a software watchdog implemented using the processor's internal timer. The timing period is configured by software to periodically check whether the system tasks are executed normally. Through program initialization, an initial value is written and the timer is started. The program assigns an initial value to the timer or resets it on time. Timeout thresholds are set for specific functional modules. If the timeout is not completed, an alarm or soft reset is triggered. The software watchdog automatically monitors the network status at regular intervals and records the reasons for disconnection, records network anomaly logs, and can be disabled by modifying its registers.

[0018] Preferably, the air conditioning data acquisition and remote upload device is directly connected to the air conditioning interface circuit and operates without the need for external microcontroller cooperation.

[0019] This patent solves the problems of complex hardware, network congestion, easy data loss, and insecure upgrades in traditional solutions through hardware integration, multi-level transmission optimization, security upgrade mechanism, and dual monitoring design. It achieves low power consumption, high reliability, easy maintenance, and strong security in the air conditioning data communication system, and is suitable for IoT scenarios such as smart homes and industrial monitoring.

[0020] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:

[0021] 1) Hardware integration:

[0022] The OpenCPU architecture is adopted, which integrates the main control chip U2A and the NB_Module module U2B, eliminating the need for an external microcontroller and simplifying the hardware design.

[0023] By using a UART level conversion circuit (MOSFET and transistor) to achieve bidirectional level matching between 5V and 3.6V, the need for external circuits is reduced, significantly lowering development and maintenance costs.

[0024] 2) High-reliability power and storage management:

[0025] Wide voltage power supply design: DC-DC (10V~20V input) and LDO (5V to 3.6V) combined power supply, outputting low noise and high stability voltage;

[0026] Dual storage area architecture: KV storage (lightweight configuration parameters) and FLASH storage (large capacity data) work together, with block-based rotation writing to extend lifespan, and automatic switching to the backup area in case of anomalies to prevent data loss;

[0027] 3) Real-time monitoring and fault recovery:

[0028] Hardware watchdog: An independent timer monitors the system's operating status; if it times out and fails to respond, it forces a reset to prevent program deadlock.

[0029] Software watchdog: Detects task timeouts based on an internal timer, logs network anomalies, and supports partial recovery;

[0030] LED status indicator: Dual-color LEDs provide real-time feedback on network connectivity, data transmission, upgrades, and fault status through constant light and flashing modes, improving operation and maintenance efficiency;

[0031] 4) Improved compatibility and security:

[0032] SIM card adaptive power supply: Supports 1.8V / 3V / 5V multi-voltage SIM cards, TVS diode (D11) suppresses surge voltage and ensures the safety of SIM card interface;

[0033] RF signal optimization: The antenna matching circuit (resistor R19 and capacitors C23 / C24) implements low-pass filtering, reduces high-frequency noise, and improves communication distance and stability. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the internal circuit architecture of an air conditioning data acquisition and remote upload device according to Embodiment 1 of this utility model.

[0035] Figure 2 This is the NB-IOT module circuit of Embodiment 1 of this utility model.

[0036] Figure 3 This is the power management circuit of Embodiment 1 of this utility model.

[0037] Figure 4 This is the UART conversion circuit of Embodiment 1 of this utility model.

[0038] Figure 5 This is the SIM card circuit of Embodiment 1 of this utility model.

[0039] Figure 6 This is the hardware watchdog circuit of Embodiment 1 of this utility model.

[0040] Figure 7 This is the LED display circuit of Embodiment 1 of this utility model. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only one preferred embodiment of this utility model and are only used to explain the technical solutions of this utility model. They do not limit the scope of protection of this utility model. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0042] Example 1:

[0043] like Figure 1As shown, this utility model provides an air conditioner data acquisition and remote upload device. This device integrates an OpenCPU architecture, including an NB-IoT module circuit and a power management circuit, as well as a SIM card circuit and a hardware watchdog circuit. The NB-IoT module circuit is connected to the power management circuit and the LED indicator circuit, and also to the SIM card circuit and the hardware watchdog circuit. The power management circuit includes a DC-DC converter circuit and an LDO converter circuit, connected to the NB-IoT module circuit and a power input port. The power input port is also connected to a UART level conversion circuit, which is connected to the NB-IoT module circuit.

[0044] Specifically, Figure 1 The circuits in the middle are described as follows:

[0045] like Figure 2 As shown, the core components of the NB-IoT module circuit mainly include the main control chip U2A, the NB_Module module U2B, and an external memory chip MX25; among them, the external memory chip MX25 is the core component of the external storage circuit, supporting firmware storage and fast reading.

[0046] The main control chip U2A connects to the antenna interface, UART level conversion circuit, SIM card circuit, hardware watchdog circuit, power management circuit, and external storage circuit. The antenna interface is connected to the antenna matching circuit via the RF_ANT pin of the main control chip U2A to optimize RF signal transmission. The antenna matching circuit consists of resistor R19 and capacitors C23 and C24, providing low-pass filtering and suppressing high-frequency noise. The UART level conversion circuit connects to the NB transceiver interface (NB_TEST_TX, NB_TEST_RX) and the NB transceiver interface (NB_TX, NB_TEST_RX). The four pins of NB_RX are connected to the main control chip U2A; the SIM card circuit is connected to the main control chip U2A through the SIM interface (SIM_DIO, SIM_CLK, SIM_RST, SIM_VDD); the hardware watchdog circuit is connected to the main control chip U2A through the NB_RST pin; the power management circuit converts the input voltage to 3.6V and then supplies power to the NB-IOT module circuit, SIM card and LED, and is connected to the power pin of the main control chip U2A; the external storage circuit is connected to the main control chip U2A through the VDD_IO interface.

[0047] The main control chip U2A is the logic control center of the system, undertaking the core functions of data preprocessing and protocol conversion, peripheral management, and power and signal coordination. The entire workflow of U2A is as follows: After the system is powered on, U2A loads firmware from external Flash and initializes the UART, SPI interface, and GPIO configuration; the air conditioner P board sends raw data to the RXD pin of U2A via UART; U2A calls the built-in protocol stack to parse the data, verifies the CRC, and adds a timestamp through the RTC module; the processed data is encapsulated into the communication protocol supported by the NB-IoT module and sent to the NB_RX of the U2B module via the TXD pin of U2A to trigger wireless transmission, while dynamically controlling the on / off and flashing mode of the LED according to the system status (networked, faulty, upgraded); if the communication of the U2B module times out, U2A starts the exponential backoff retransmission mechanism, and the red LED flashes rapidly to indicate the fault; the power supply voltage (VBAT) is monitored, and when power fluctuations are detected, the system switches to the backup power supply (such as a supercapacitor) and records the abnormality log; when the voltage is abnormal, a low-power mode or alarm is triggered; U2A controls the start and stop of peripheral circuits (such as relays and sensor power supplies) through GPIO pins to optimize system power consumption.

[0048] The NB_Module U2B connects to the external storage circuit via an SPI interface and is primarily responsible for the module's wireless communication. Additionally, the NB_Module U2B includes a software watchdog timer implemented using the processor's internal timer. The timer period is configured via software to periodically check whether system tasks are executing correctly. Initialization is performed by writing initial values ​​and starting the timer. The program initializes or resets the timer on schedule. Timeout thresholds are set for specific functional modules; failure to complete the timeout triggers an alarm or soft reset. The software watchdog automatically monitors network status and records disconnection reasons, logging network anomalies. It can be disabled by modifying its registers.

[0049] The NB_Module U2B is the core of the system's wireless communication, responsible for cellular network access, data transmission, and security authentication. The entire workflow of the U2B is as follows: After establishing a connection with the base station, it registers the device with the operator's network (APN configuration), obtains an IP address, and maintains a heartbeat connection; it uploads the protocol data encapsulated by the U2A to the cloud platform via PSM (power saving mode) or eDRX (extended discontinuous reception); it receives control commands (such as temperature adjustment and firmware upgrades) from the cloud, parses them, and transmits them back to the U2A for execution via UART; simultaneously, after power-on, it reads the SIM card IMSI via SIM_CLK (1-5MHz clock) and SIM_DIO (data line) to complete network attachment; in abnormal scenarios (such as SIM card removal), an interrupt is triggered, and the U2B notifies the U2A to record the fault event.

[0050] like Figure 3As shown, the power management circuit mainly includes a DC-DC conversion circuit and an LDO conversion circuit, which provide a stable power supply for the NB-IoT module and peripheral circuits to prevent voltage fluctuations from damaging the equipment; TVS diodes (D1, D2, D8) are connected in parallel at the power input terminal to suppress surge voltage.

[0051] The DC-DC converter circuit is connected to the power input port, accepting a wide voltage range of 10V to 20V (DCIN). After conversion by the DC-DC converter, it outputs a 5V voltage, which is filtered by inductor L1 (47μH) and capacitor. The output terminal is connected to the input terminal of the LDO converter circuit. The LDO converter circuit mainly includes an LDO regulator chip U1, which is responsible for reducing the 5V output voltage of the DC-DC converter circuit to 3.6V to power the NB-IoT module. Capacitors C1, C2, and C4 are used for decoupling. The output terminal of the LDO regulator chip U1 is connected to the power pin of the NB-IoT module circuit.

[0052] like Figure 4 As shown, the UART level conversion circuit is responsible for solving the communication compatibility problem between the 5V power supply voltage of the main control chip U2A and the 3.6V power supply voltage of the NB_Module module U2B in the NB-IOT module circuit. It includes the core components N-channel MOSFETs Q1 and Q2, as well as NPN transistors Q3 and Q4. Q1 / Q2 handle the main UART channel (TXD / RXD), while Q3 / Q4 are dedicated to the debug interface (DBG_TXD / DBG_RXD). The independent channels avoid signal crosstalk.

[0053] The drain (D) of MOSFET Q1 is connected to the 5V output of the DC-DC converter circuit via resistor R3, the gate (G) is grounded, and the source (S) is connected to the NB_RX interface of the NB-IoT module circuit main control chip U2A. The drain (D) of MOSFET Q2 is connected to the 5V output of the DC-DC converter circuit via resistor R4, the gate (G) is grounded, and the source (S) is connected to the NB_TX interface of the NB-IoT module circuit main control chip U2A. The base (B) pin of transistor Q3 is connected to the VDD_IO pin of the low-voltage side NB-IoT module circuit main control chip U2A, the emitter (E) pin is connected to the NB_TEST_TX pin of the high-voltage side NB-IoT module circuit main control chip U2A, and the collector (C) pin is connected to a fixed level of 5V via current-limiting resistor R27. The base (B) pin of transistor Q4 is connected to a fixed level of 5V via current-limiting resistor R28, the emitter (E) pin is connected to the low-voltage side signal line, and the collector (C) pin is connected to the NB_TEST_RX pin of the high-voltage side NB-IoT module circuit main control chip U2A.

[0054] The working process of the UART level conversion circuit is as follows:

[0055] 1) Main controller sends signal (5V→3.6V):

[0056] When the main control outputs a high level (5V), the gate G voltage of Q1 is higher than the threshold (Vth≈2.1V), the MOSFET is turned on, and NB_TX is pulled low to 0V; the base B of Q3 obtains a bias voltage through R26, the transistor is saturated and turned on, and the collector C is pulled down to ground, causing DBG_TXD on the NB module side to become a high level of 3.6V through the pull-up resistor (R27);

[0057] When the main control output is low (0V), Q1 is cut off, and R3 (10K) pulls NB_TX up to 3.6V; when Q3 is cut off, DBG_TXD on the NB module side is pulled up to 3.6V.

[0058] 2) NB module sends signals (3.6V→5V):

[0059] When the NB module outputs a high level (3.6V), the gate voltage of Q2 is insufficient to turn on, and R4 (10K) pulls the main control terminal up to 5V; Q4 turns on, and the main control side DBG_RXD is pulled low to 0V;

[0060] When the NB module outputs a low level (0V), Q2 is turned on, and the main control RXD is pulled low to 0V; Q4 is turned off, and the main control side is restored to 5V through the pull-up resistor (R28).

[0061] like Figure 5 As shown, the SIM card circuit is connected to the main control chip U2A, the SIM card socket J4, and the telecom MFF2 chip U3 via four SIM pins (SIM_DIO, SIM_CLK, SIM_RST, SIM_VDD). The SIM card socket J4 is a nano SIM card socket, supporting hot-swapping, and contains six pins (VCC, RST, CLK, GND, VPP, IO). VCC and GND provide power and grounding loops, while CLK, RST, and IO are the transmission clock, reset, and data signals. A surface-mount transient voltage suppressor diode D11 is connected in parallel between its VCC and GND pins, positioned close to the SIM card socket J4 to shorten the protection path. The input side of the telecom MFF2 chip U3 is connected to the four SIM pins of the NB-IoT module circuit's main control chip U2A, and the output side is connected to the corresponding pins of the SIM card socket J4. Decoupled by filter capacitors C5-C8, it mainly converts the 3.6V signal output by the main control chip U2A into a voltage supported by the SIM card, preventing overvoltage damage to the SIM card.

[0062] The four SIM pins of the main control chip U2A are defined and connected as follows: the SIM_DIO pin is directly connected to the IO pin of the SIM card slot J4 for transmitting APDU commands and responses; the SIM_CLK pin outputs a clock signal to the CLK pin of the SIM card slot J4, with a frequency range of 1-5MHz, to synchronize data transmission timing; the SIM_RST pin outputs a reset pulse to the RST pin of the SIM card slot J4 for initializing the SIM card or forcibly restarting; and the SIM_VDD pin provides 3.6V power to the VCC pin of the SIM card slot J4, supporting 1.8V, 3V and 5V power supply self-adaptation.

[0063] The working principle of the above SIM card circuit is as follows:

[0064] 1) Initialization phase: After inserting the SIM card, the U2A is powered on via SIM_VDD, detects the card type and adjusts the power supply voltage; sends a reset signal (SIM_RST high level → low level → high level), reads the SIM card's ATR (Reset Response) information, and confirms the protocol version and communication parameters;

[0065] 2) Data transmission phase: U2A synchronizes the clock via SIM_CLK and sends APDU commands via SIM_DIO; the SIM card returns a status word (SW1 / SW2) and data, which U2A parses to complete authentication or data operation;

[0066] 3) Abnormal handling: If the SIM card communication times out or the verification fails, U2A triggers SIM_RST reset to reinitialize the communication link.

[0067] like Figure 6 As shown, the hardware watchdog circuit connected to the main control chip U2A is a timer circuit. The reset pin NB_RST is connected to the system reset terminal of the NB-IoT module circuit through a pull-up resistor R14. The hardware watchdog (WDT) monitors the system's operating status to prevent program deadlock or abnormal crashes. When the system starts, the main program configures the watchdog timeout (e.g., 10 seconds) and begins periodically "feeding" the watchdog (sending a reset signal to the WDT). If the main program fails to feed the watchdog on time due to a fault, the timer overflows, triggering a reset signal (low-level pulse), forcing the NB-IoT module circuit to restart. The hardware watchdog circuit starts immediately when the system powers on, operates independently of the system's main processor, is unaffected by software faults, and cannot be disabled or bypassed by software, ensuring that the monitoring mechanism is always effective.

[0068] like Figure 7As shown, the LED indicator circuit includes two dual-color LEDs, green (D6) and red (D7), which are connected to the GPIO pins NB_LED1 and NB_LED2 of the NB-IoT module's main control chip U2A via current-limiting resistors R7 and R8, respectively. Different colors and constant illumination / blinking modes convey multi-dimensional information, intuitively displaying the module's operating status. The green LED (D6) indicates the device's network connection status (e.g., successful NB-IoT module registration with a base station), normal data transmission, or normal system operation. The red LED (D7) indicates abnormal status (e.g., network disconnection, sensor failure, firmware upgrade in progress, or hardware error). A solid green light indicates the device is online and idle; a slow flashing green light indicates data upload in progress; a fast flashing red light indicates an upgrade in progress; and a solid red light indicates a serious fault alarm. During system development, the LED status can help locate problems such as communication interruptions and power failures.

[0069] The firmware of the NB-IoT module controls the LED's on / off state by configuring the GPIO pin to output mode: when the GPIO output is low, the LED cathode is grounded to form a loop, current flows through the LED and the current-limiting resistor, and the LED lights up; when the GPIO output is high, the cathode and anode voltages are equal, the loop is broken, and the LED turns off.

[0070] Different blinking modes can be achieved by adjusting the frequency of GPIO level changes through software timers or PWM (pulse width modulation): 1Hz blinking can be achieved by periodically switching between high and low levels (500ms low level + 500ms high level); combined with dual-color LEDs, multi-state encoding can be extended to include more state combinations: such as green light flashing + red light staying on indicates that the network connection is normal but the sensor data is abnormal; red and green alternating blinking indicates that the system self-test has failed, etc.

[0071] Troubleshooting and debugging of LED indicator circuits:

[0072] If the LED does not light up for a long time, it may be due to incorrect GPIO configuration, poor resistor soldering, or LED damage. You can use a multimeter to measure the GPIO level and circuit continuity to troubleshoot the problem.

[0073] If the actual blinking frequency of the LED does not match the design, the system clock configuration or the accuracy of the software timer should be checked, and the firmware code should be adjusted if necessary.

[0074] LED compatibility verification: LED visibility is tested under different ambient lighting conditions to ensure that status indicators can be clearly identified in both indoor and outdoor scenarios.

[0075] In summary, this utility model discloses an air conditioner data acquisition and remote upload device, applied to an air conditioner data communication system. It includes an NB-IoT module circuit integrating an OpenCPU architecture, a power management circuit, a SIM card circuit, and a hardware watchdog circuit. The module works collaboratively with the main control chip U2A and the NB_Module U2B. The main control chip connects to the antenna interface, UART level conversion circuit, SIM card circuit, and hardware watchdog circuit to achieve data acquisition, protocol parsing, and wireless communication. The power management circuit uses a combination of DC-DC and LDO, supporting a wide voltage input of 10V to 20V and a stable 3.6V output. The UART level conversion circuit uses MOSFETs and transistors to achieve bidirectional level matching between 5V and 3.6V, ensuring communication compatibility between the main control chip and the NB module. The SIM card circuit integrates TVS protection and adaptive power supply, supporting multi-voltage SIM cards. A dual monitoring mechanism of hardware and software watchdog prevents system deadlock. The device's software employs discrete network entry, peak-shifting reporting, missed report compensation, and exponential backoff retransmission algorithms to improve data transmission reliability, and provides real-time status feedback through dual-color LED indicators. This solution addresses the technical problems of traditional technologies, such as complex hardware, network congestion, and easy data loss, and offers advantages such as low power consumption, high reliability, and ease of maintenance.

[0076] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. It should be noted that for those skilled in the art, any changes or substitutions that can be easily conceived without departing from the technical principle of the present invention should be included within the protection scope of the present utility model.

Claims

1. An air conditioning data acquisition and remote upload device, applied to an air conditioning data communication system, characterized in that, The system integrates an OpenCPU architecture, including an NB-IoT module circuit and a power management circuit, as well as a SIM card circuit and a hardware watchdog circuit. The NB-IoT module circuit is connected to the power management circuit and the LED indicator circuit, and also to the SIM card circuit and the hardware watchdog circuit. The power management circuit includes a DC-DC converter circuit and an LDO converter circuit, which are connected to the NB-IoT module circuit and the power input port. The power input port is also connected to a UART level conversion circuit, which is connected to the NB-IoT module circuit.

2. The air conditioning data acquisition and remote upload device according to claim 1, characterized in that, The core components of the NB-IoT module circuit mainly include the main control chip U2A and the NB_Module U2B, as well as the external memory chip MX25. The NB_Module U2B is connected to the external memory chip MX25 through the SPI interface and is mainly responsible for the wireless communication of the module.

3. The air conditioning data acquisition and remote upload device according to claim 2, characterized in that, The main control chip U2A connects to the antenna interface and UART level conversion circuit, SIM card circuit and hardware watchdog circuit, as well as power management circuit and external storage circuit. The antenna interface connects to the antenna matching circuit via the RF_ANT pin of the main control chip U2A to optimize RF signal transmission. The antenna matching circuit consists of resistor R19 and capacitors C23 and C24, providing low-pass filtering to suppress high-frequency noise. The UART level conversion circuit connects to the main control chip U2A via the NB_TEST transceiver interface and four pins of the NB transceiver interface. The SIM card circuit connects to the main control chip U2A via the SIM interface. The hardware watchdog circuit connects to the main control chip U2A via the NB_RST pin. The power management circuit converts the input voltage to 3.6V to power the NB-IoT module circuit, SIM card, and LED, and connects to the power pin of the main control chip U2A. The core component of the external storage circuit is the external memory chip MX25, which supports firmware storage and fast retrieval, and connects to the main control chip U2A via the VDD_IO interface.

4. An air conditioning data acquisition and remote uploading device according to claim 1 or 3, characterized in that, The power management circuit provides a stable power supply to the NB-IoT module and peripheral circuits to prevent voltage fluctuations from damaging the device. It includes a DC-DC conversion circuit and an LDO conversion circuit. The DC-DC conversion circuit is connected to the power input port, accepting a wide voltage range of 10V~20V (DCIN). After conversion by the DC-DC converter, it outputs a 5V voltage, and its output terminal is connected to the input terminal of the LDO conversion circuit. The LDO conversion circuit mainly includes an LDO voltage regulator chip U1, which is responsible for reducing the 5V voltage output by the DC-DC conversion circuit to 3.6V. The output terminal of the LDO voltage regulator chip U1 is connected to the power pin of the NB-IoT module circuit.

5. An air conditioning data acquisition and remote uploading device according to claim 1 or 2, characterized in that, The UART level conversion circuit is responsible for resolving the communication compatibility issue between the 5V power supply voltage of the main control chip U2A and the 3.6V power supply voltage of the NB_Module module U2B in the NB-IoT module circuit. It includes core components N-channel MOSFETs Q1 and Q2, as well as NPN transistors Q3 and Q4. The drain (D) of MOSFET Q1 is connected to the 5V output of the DC-DC conversion circuit via resistor R3, its gate (G) is grounded, and its source (S) is connected to the NB_RX interface of the main control chip U2A in the NB-IoT module circuit. Similarly, the drain (D) of MOSFET Q2 is connected to the 5V output of the DC-DC conversion circuit via resistor R4, its gate (G) is grounded, and its source (S) is connected to the NB_RX interface of the main control chip U2A in the NB-IoT module circuit. Connect the transistor Q3 to the NB_TX interface of the NB-IoT module circuit main control chip U2A; the B-pin of the transistor Q3 is connected to the VDD_IO pin of the low-voltage side NB-IoT module circuit main control chip U2A, the E-pin is connected to the NB_TEST_TX pin of the high-voltage side NB-IoT module circuit main control chip U2A, and the C-pin is connected to a fixed level of 5V through a current-limiting resistor R27; the B-pin of the transistor Q4 is connected to a fixed level of 5V through a current-limiting resistor R28, the E-pin is connected to the low-voltage side signal line, and the C-pin is connected to the NB_TEST_RX pin of the high-voltage side NB-IoT module circuit main control chip U2A.

6. The air conditioning data acquisition and remote upload device according to claim 1, characterized in that, The LED indicator circuit includes two dual-color LED indicators, green LED D6 and red LED D7, which are connected to the GPIO pins NB_LED1 and NB_LED2 of the NB-IoT module's main control chip U2A via current-limiting resistors R7 and R8, respectively. Different colors and constant illumination / blinking modes convey multi-dimensional information, intuitively displaying the module's operating status. Green LED D6 indicates the device's network status, normal data transmission, or normal system operation; red LED D7 indicates an abnormal state. A constant green light indicates the device is online and idle; a slow flashing green light indicates data upload in progress; a fast flashing red light indicates an upgrade in progress; and a constant red light indicates a serious fault alarm.

7. An air conditioning data acquisition and remote uploading device according to claim 1 or 3, characterized in that, The SIM card circuit is connected to the main control chip U2A via four SIM pins, mainly including the SIM card socket J4 and the telecom MFF2 chip U3. The SIM card socket J4 is a nano SIM card socket, supports hot-swapping, and has 6 pins. A surface-mount transient voltage suppression diode D11 is connected in parallel between its VCC and GND pins, positioned close to the SIM card socket J4 to shorten the protection path. The input side of the telecom MFF2 chip U3 is connected to the four SIM pins of the NB-IoT module circuit main control chip U2A, and the output side is connected to the corresponding pins of the SIM card socket J4. It is decoupled by filter capacitors C5~C8 and is mainly used to convert the 3.6V signal output by the main control chip U2A into a voltage supported by the SIM card to prevent overvoltage damage to the SIM card.

8. The air conditioning data acquisition and remote upload device according to claim 7, characterized in that, The SIM pins include the SIM_DIO pin and the SIM_CLK pin, as well as the SIM_RST pin and the SIM_VDD pin: the SIM_DIO pin is directly connected to the IO pin of the SIM card slot J4 and is used to transmit APDU commands and responses; the SIM_CLK pin outputs a clock signal to the CLK pin of the SIM card slot J4, with a frequency range of 1-5MHz, to synchronize data transmission timing; the SIM_RST pin outputs a reset pulse to the RST pin of the SIM card slot J4 for initializing the SIM card or forcibly restarting; the SIM_VDD pin provides 3.6V power to the VCC pin of the SIM card slot J4 and supports 1.8V, 3V and 5V power supply adaptation.

9. The air conditioning data acquisition and remote upload device according to claim 2, characterized in that, The hardware watchdog circuit connected to the main control chip U2A is a timer circuit. The reset pin NB_RST is connected to the system reset terminal of the NB-IoT module circuit through a pull-up resistor R14. The program clears the timer within a certain time range to monitor the system's operating status. When the program is working normally, the timer does not overflow and does not generate a reset signal. If the program times out without responding, it triggers a reset and restarts the system to prevent program deadlock. The hardware watchdog circuit starts immediately when the system is powered on, operates independently of the system's main processor, is not affected by software failures, and cannot be disabled or bypassed by software, ensuring that the monitoring mechanism is always effective. The NB_Module U2B has a software watchdog, implemented using the processor's internal timer. The timing period is configured by software to periodically check whether the system tasks are executed normally. Through program initialization, an initial value is written and the timer is started. The program assigns an initial value to the timer or resets it on time. Timeout thresholds are set for specific functional modules. If the timeout is not completed, an alarm or soft reset is triggered. The software watchdog automatically monitors the network status at regular intervals and records the reasons for disconnection, records network anomaly logs, and can be disabled by modifying its registers.

10. An air conditioning data acquisition and remote uploading device according to claim 1, characterized in that, The air conditioning data acquisition and remote upload device connects directly to the air conditioning interface circuit and operates without the need for an external microcontroller.

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