Long-acting self-powered internet of things node system in weak light environment

Abstract

The application discloses a long-acting self-powered Internet of Things node system in a weak light environment, and belongs to the technical field of Internet of Things and micro energy collection, which comprises a light energy collection unit, an energy management unit, a gate control unit and a load unit which are connected in sequence; the light energy collection unit collects ambient light in a weak light environment and outputs photovoltaic voltage; the energy management unit boosts the photovoltaic voltage to a working voltage and stores energy; the gate control unit controls the power supply on and off of the load unit; the load unit collects target data and sends a feedback signal to the gate control unit, triggering the gate control unit to cut off the power supply path of the load unit, so that the system enters a low-power consumption state. The gate control unit is arranged to realize the hardware level power-off control of the load unit in the standby stage, reduce the system static power consumption and energy storage consumption, improve the energy utilization efficiency and continuous operation capacity in the weak light environment, and thus realize the long-term maintenance-free self-powered operation of the indoor micro-power consumption Internet of Things node.

Description

Technical Field

[0001] This invention belongs to the field of Internet of Things and micro-energy harvesting technology, specifically relating to a long-lasting self-powered Internet of Things node system in low-light environments. Background Technology

[0002] With the rapid development of Internet of Things (IoT) technology, the number of wireless environmental monitoring and sensing nodes deployed globally has surged. Traditional sensing nodes mainly rely on disposable chemical batteries for power, which not only brings high costs for manual replacement and maintenance, and environmental pollution from discarded batteries, but also makes them highly susceptible to sudden power outages and loss of critical data due to battery depletion. Therefore, utilizing ambient energy to enable self-powered operation of IoT nodes has become an important development direction in the current IoT field. Among them, photovoltaic self-powered solutions that utilize indoor ambient light for energy harvesting have attracted widespread attention due to their advantages such as a wide range of energy sources and no need for additional maintenance. However, indoor ambient light intensity is usually only 200 lux to 1000 lux, far lower than outdoor sunlight conditions. Therefore, the output power that photovoltaic devices can obtain is very limited, usually only in the range of tens to hundreds of microwatts. Under these conditions, the energy that the system can obtain is on the same order of magnitude as the energy consumed by the system, or even lower than the system power consumption, thus placing higher demands on the overall power consumption control of the system.

[0003] Existing wireless sensor nodes typically employ a microcontroller (MCU)-based software sleep control method to achieve periodic operation. In this approach, the microcontroller enters a low-power sleep state after completing data acquisition and wireless transmission, and then wakes up to execute tasks after a preset time. Although software sleep can reduce system power consumption, the system still experiences static current consumption because the voltage regulator circuit, the microcontroller's internal circuitry, and some peripheral devices remain powered during sleep.

[0004] For self-powered systems using indoor photovoltaic power, the persistent standby power consumption will deplete the energy reserves in energy storage devices over a long period. Especially in lighting-deficient scenarios such as nighttime, weekends, or prolonged periods of unused use, the system cannot obtain external energy replenishment, yet standby power consumption continues, easily leading to the gradual depletion of energy in storage devices such as supercapacitors. When the energy storage voltage drops below the system's normal operating voltage, the system may experience wireless communication failures, repeated microcontroller resets, or even complete inability to continue operating, severely impacting the long-term stable operation of self-powered IoT nodes.

[0005] Therefore, how to further reduce the power consumption of the system during standby, reduce the ineffective energy loss of energy storage devices, and improve the system's continuous operation capability in long-term low-light environments, while ensuring periodic data acquisition and wireless communication functions, has become an urgent technical problem to be solved in the field of self-powered IoT nodes. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a long-term self-powered IoT node system for low-light environments. By setting up a gating control unit between the energy management unit and the load unit, hardware-level power-off control of the load unit during standby is achieved, effectively reducing the system's static power consumption and energy storage consumption, improving energy utilization efficiency and continuous operation capability in low-light environments, thereby enabling long-term maintenance-free self-powered operation of indoor low-power IoT nodes.

[0007] The technical solution adopted in this invention is as follows:

[0008] A long-lasting self-powered Internet of Things (IoT) node system for low-light environments includes a light energy acquisition unit, an energy management unit, a gating control unit, and a load unit connected in sequence.

[0009] The light energy harvesting unit is used to harvest ambient light in low-light environments and output photovoltaic voltage;

[0010] The energy management unit is used to boost the photovoltaic voltage to the operating voltage and store energy.

[0011] The gate control unit is used to control the power supply to and from the load unit, and specifically includes a drive end, a feedback signal receiving end, and a power input end. The power input end is connected to the energy management unit. When the energy storage voltage of the energy management unit reaches the operating voltage of the gate control unit, it triggers the gate control unit to complete the power supply to enable the load unit to enter the wake-up period.

[0012] The load unit includes a voltage regulator circuit, a sensor module, and a microcontroller. The voltage regulator circuit is connected to the drive terminal of the gate control unit to convert the input operating voltage into a stable voltage. The power supply terminal of the sensor module is connected to the output terminal of the voltage regulator circuit, and its communication terminal is connected to the microcontroller to collect target data and transmit it to the microcontroller. The power supply terminal of the microcontroller is connected to the output terminal of the voltage regulator circuit, and its feedback terminal is connected to the feedback signal receiving terminal of the gate control unit to send a feedback signal to the gate control unit after completing the target data processing or transmission, thereby triggering the gate control unit to complete the power supply shutdown and put the load unit into a sleep state.

[0013] Furthermore, the gate control unit is designed based on a hardware timer and controls the periodic wake-up sampling time interval of the system by configuring a timer cycle.

[0014] Furthermore, the load unit also includes a communication module for sending target data to an external terminal or gateway device, and triggering the microcontroller to send a feedback signal to the gate control unit after the transmission is completed.

[0015] Furthermore, the communication module is a wireless communication module and is integrated inside the microcontroller.

[0016] Furthermore, the sensor module is at least one of an environmental sensor, a microampere-level current detection sensor, and a biochemical detection sensor.

[0017] Furthermore, the energy management unit includes a boost converter with cold start function and an energy storage capacitor; wherein, the boost converter is used to boost the photovoltaic voltage to the operating voltage; and the energy storage capacitor is used to store energy from the operating voltage.

[0018] Furthermore, the energy storage capacitor is a supercapacitor.

[0019] Furthermore, the energy management unit also includes a maximum power point tracking (MPPT) controller integrated with the boost converter for dynamically adjusting the input impedance of the boost converter to match the maximum power point of the light energy harvesting unit.

[0020] Furthermore, the light energy harvesting unit includes multiple perovskite solar sub-cells connected in series. Each perovskite solar sub-cell includes a first electrode, an intermediate functional layer, and a second electrode stacked sequentially. At least one side of the first electrode extends outward to form a first connection portion, so that the first electrode is connected to the second electrode of its adjacent sub-cell through the first connection portion to achieve series connection. A physical gap is formed between the first connection portion and the intermediate functional layer so that they do not contact each other.

[0021] Furthermore, the number of perovskite solar sub-cells in series in the light energy harvesting unit is configured such that the output photovoltaic voltage is greater than the cold start threshold voltage of the boost converter.

[0022] Furthermore, the effective light-receiving area of ​​the light energy harvesting unit is configured such that its output power in a low-light environment is greater than the average power consumption of the system during periodic operation.

[0023] Furthermore, the average power consumption during periodic operation is the average of the data acquisition and transmission power consumption of the load unit during the wake-up period and the static leakage power consumption during the sleep period.

[0024] Furthermore, the load unit is also equipped with an output filtering and feedback protection circuit, specifically including a first capacitor, a resistor, and a second capacitor. The first capacitor is connected between the output terminal of the voltage regulator circuit and ground to filter and store energy for the stable voltage. The resistor is connected in series between the feedback terminal of the microcontroller and the feedback signal receiving terminal of the gate control unit to limit the feedback pulse current, protect the feedback terminal interface, and improve the stability of the feedback signal transmission. The second capacitor is connected between the feedback signal receiving terminal of the gate control unit and ground to debouncing and transient filtering the feedback signal to prevent noise interference from causing the gate control unit to be falsely triggered and shut down.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention proposes a long-lasting self-powered IoT node system in low-light environments. By setting a gating control unit between the energy management unit and the load unit, the power supply path of the voltage regulator circuit and the load unit is physically shut down at the hardware level during the system's sleep phase, thereby effectively reducing the static leakage power consumption of the downstream circuits. This low standby power consumption mechanism can significantly reduce the average power consumption during the system's periodic operation, and is particularly suitable for application scenarios with limited energy storage and charging capabilities in low-light environments, thus ensuring the long-lasting self-powered operation of the IoT node system.

[0027] 2. Preferably, the light energy harvesting unit of the present invention adopts a perovskite module based on edge interconnection. Physical isolation is achieved by utilizing the gap formed between the first connection portion extending from the first electrode and the intermediate functional layer. This suppresses the lateral diffusion path of electrode metal ions under continuous illumination from the source, ensuring that the internal parallel resistance of the photovoltaic module remains high and the output power and voltage do not drop after long-term service. This structure can improve the output stability of the photovoltaic module during long-term operation, slow down the attenuation of output power and output voltage, and thus improve the stable start-up capability of the downstream energy management unit during long-term system operation.

[0028] 3. This invention reduces the risk of traditional IoT nodes running out of energy due to continuous leakage in soft sleep mode under long-term lightless environment by coordinating the stable energy output of the front-end light energy acquisition unit with the low standby power consumption gating mechanism at the back end. At the same time, the system can still maintain a dynamic balance between the output energy and the average power consumption of the system in indoor low light environment (200 lux to 1000 lux), thereby improving the system's stable operation under long-term day and night cycle conditions and realizing the long-term maintenance-free operation of self-powered IoT nodes. Attached Figure Description

[0029] Figure 1 The overall circuit diagram of the self-powered IoT node system without a gate control unit proposed in Comparative Example 1 is shown.

[0030] Figure 2 This is the overall circuit diagram of the long-lasting self-powered IoT node system in low-light environment proposed in Example 1;

[0031] Figure 3 This is a schematic diagram of the edge interconnect structure perovskite solar module in Example 1 and a traditional module;

[0032] Figure 4The JV curve (a) and the spectral irradiance as a function of wavelength (b) of the edge interconnect structure perovskite solar module in Example 1 under low indoor illuminance ranging from 250 lux to 1000 lux.

[0033] Figure 5 The normalized path current density Jsc, open-circuit voltage Voc, fill factor FF, and photoelectric conversion efficiency PCE of the edge interconnect structure perovskite solar modules in Comparative Example 1 and Example 1 under continuous 86 days of light aging at 1000 lux are shown as changes over time.

[0034] Figure 6 This is a comparison graph showing the voltage decrease over time of the supercapacitors in Comparative Example 1 and Example 1.

[0035] Figure 7 The indoor temperature and humidity change curves are periodically collected in actual deployment scenarios for the systems proposed in Comparative Example 1(a) and Example 1(b). Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0037] Example 1

[0038] This embodiment proposes a long-lasting self-powered IoT node system for low-light environments, with the structure as follows: Figure 2 As shown, it includes a light energy harvesting unit, an energy management unit, a gating control unit, and a load unit connected in sequence.

[0039] The light energy harvesting unit is used to harvest ambient light in low-light environments and output photovoltaic voltage. Specifically, it is a perovskite (wide bandgap 1.78 eV) solar module with a series-connected edge-interconnected structure, as shown in the figure. Figure 3 As shown, the module includes multiple perovskite solar sub-cells connected in series. The positive electrode (Vpv) is connected to the power management unit, and the negative electrode is grounded. Each perovskite solar sub-cell is designed based on an edge-type interconnected series structure, including a first electrode, an intermediate functional layer (containing a perovskite layer), and a second electrode stacked sequentially. At least one side of the first electrode extends outward to form a first connection portion, so that the first electrode is connected to the second electrode of its adjacent sub-cell through the first connection portion to achieve series connection. Furthermore, a non-contact gap is formed between the first connection portion and the intermediate functional layer to suppress the diffusion of metal ions into the perovskite layer, thereby improving the stability of the module's long-term operation and ensuring continuous output capability under low light conditions.

[0040] In this embodiment, the number of perovskite solar sub-cells in series in the light energy harvesting unit is configured to be 3, ensuring that its output photovoltaic voltage is greater than the cold start threshold voltage of the boost converter (approximately 330mV) under indoor low illumination of 250 lux; the effective light-receiving area of ​​the light energy harvesting unit is configured to be 2.1 cm². 2 This ensures that its output power in low-light environments is greater than the average power consumption of the system during periodic operation, which is the average of the data acquisition and transmission power consumption of the load unit during the wake-up period and the static leakage power consumption during the sleep period.

[0041] The energy management unit is used to boost the photovoltaic voltage to the operating voltage and store energy to achieve energy accumulation and cold start power supply. Specifically, it includes an energy management unit U1 (such as CJMCU-25505) and an energy storage supercapacitor C1 (e.g., 0.47 F, 5.5 V). The VIN_DC input terminal of the energy management unit U1 is connected to the positive terminal Vpv of the photovoltaic energy harvesting unit. It integrates a maximum power point tracking controller and a boost converter, which is used to boost the photovoltaic voltage to the operating voltage. The energy storage supercapacitor C1 is connected to the VBAT pin of the energy management unit U1 to store energy from the operating voltage.

[0042] The gate control unit is designed based on an ultra-low power hardware timer U2 (such as TPL5110). By configuring the timing period, it controls the power supply to the load unit and shuts it off, i.e., it controls the periodic wake-up sampling time interval of the system. Specifically, it includes a driver terminal (DRV output pin), a feedback signal receiver terminal (DONE feedback pin), and a power input terminal (VDD pin). The power input terminal is connected to the energy storage supercapacitor C1. When the energy storage voltage of the supercapacitor C1 reaches the operating voltage of the gate control unit, it triggers the gate control unit to complete the power supply conduction, and the load unit enters the wake-up period. Compared to traditional control methods based on MCU software sleep mode, this embodiment cuts off the power supply path of the subsequent stage through hardware-level physical power-off, thereby effectively reducing the static power consumption during the system standby phase.

[0043] The load unit includes a voltage regulator circuit U3 (such as HT7333-A), a microcontroller U4 (such as an nRF52840 module), a sensor module U5 (such as an SHT40 temperature and humidity sensor), and a wireless communication module integrated within the microcontroller U4. The power input terminal VIN of the voltage regulator circuit U3 is connected to the drive terminal of the gate control unit to convert the input operating voltage into a stable 3.3V. The power supply terminal of the sensor module U5 is connected to the output terminal of the voltage regulator circuit U3 and connected to the microcontroller U4 via an I2C bus to collect ambient temperature and humidity data and output it to the microcontroller U4. The wireless communication module is used to transmit ambient temperature and humidity data. The power supply terminal of the microcontroller U4 is connected to the output terminal VOUT of the voltage regulator circuit U3, and its feedback terminal (D3 pin, i.e., GPIO pin) is connected to the feedback signal receiving terminal of the gate control unit. After transmitting the ambient temperature and humidity data, the microcontroller U4 sends a feedback signal to the gate control unit to trigger it to shut down, and the load unit enters a sleep state.

[0044] The load unit also includes an output filtering and feedback protection circuit, specifically comprising capacitor C2 (e.g., 100 μF), resistor R1 (e.g., 1 kΩ), and capacitor C3 (e.g., 100 nF). Capacitor C2 is connected between the output of the voltage regulator circuit U3 and ground, used to filter and store energy at the stable 3.3 V voltage, suppressing voltage fluctuations caused by transient loads in wireless communication, and improving the power supply stability of the microcontroller U4 and sensor module U5 during operation; this is part of the voltage regulation output filtering section of the load unit. Resistor R1 is connected in series between the D3 pin of the microcontroller U4 and the DONE feedback pin of the hardware timer U2, used to limit the feedback pulse current, protect the GPIO interface, and improve the stability of feedback signal transmission; this is part of the feedback control interface between the gate control unit and the load unit. Capacitor C3 is connected between the DONE feedback pin of the hardware timer U2 and ground, used to debouncing and transiently filtering the DONE feedback signal, preventing noise interference from causing the hardware timer U2 to be falsely triggered and shut down; this is part of the feedback signal filtering section of the gate control unit.

[0045] It should be noted that the specific chip models mentioned in this embodiment (such as the CJMCU-25505 boost converter, TPL5110 hardware timer, HT7333-A voltage regulator circuit, nRF52840 microcontroller, etc.) are only preferred embodiments. Those skilled in the art will understand that any replacement electronic device with the same or similar functions, such as an energy management chip with cold start functionality, a low-power timing control chip with hardware driver and feedback interfaces, or a low static power regulator chip, should fall within the protection scope of this invention.

[0046] The operation flow of the long-term self-powered IoT node system in low-light environments proposed in this embodiment is as follows:

[0047] (1) Charging and energy accumulation stage

[0048] After system startup, the light energy harvesting unit continuously collects ambient light energy in low-light indoor environments and charges the supercapacitor C1 via the energy management chip U1. The maximum power point tracking controller integrated within the energy management chip U1 optimizes the input energy to improve energy harvesting efficiency under low-light conditions. During the system cold start and energy accumulation phases, the hardware timer U2 keeps the voltage regulator circuit U3 off, disconnecting the power supply path between the downstream load unit and the supercapacitor C1. This prevents the downstream circuit from prematurely consuming the harvested meager energy, improving the system's cold start success rate and energy storage efficiency in low-light environments.

[0049] (2) Wake-up sampling phase:

[0050] When the energy storage voltage of the supercapacitor C1 reaches the operating voltage of the hardware timer U2, the DRV output pin of the hardware timer U2 outputs a high level (or turns on the MOS switch), connecting the power supply circuit of the voltage regulator circuit U3. Subsequently, the voltage regulator circuit U3 outputs a stable operating voltage to power the microcontroller U4, sensor module U5, and wireless communication module. After the microcontroller U4 powers on, it drives the sensor module U5 to collect ambient temperature and humidity data and sends the collected data to an external gateway or terminal device via a wireless communication protocol. The gate control unit U2 can configure the timing period via an adjustable resistor on the module board, thereby controlling the periodic wake-up sampling time interval of the system.

[0051] (3) Deep standby phase:

[0052] After the wireless transmission is complete, the microcontroller U4 outputs a high-pulse feedback signal to the DONE pin of the hardware timer U2 via the D3 pin. Upon receiving the feedback signal, the hardware timer U2 immediately shuts down the DRV output, cutting off the input power supply path to the voltage regulator circuit U3, and the system enters a deep standby state. At this time, the timing module inside the hardware timer U2 continues to run, while the voltage regulator circuit U3 and the subsequent load unit are physically de-energized. Therefore, the microcontroller U4, sensor module U5, and wireless communication module no longer consume operating current.

[0053] During deep standby, the system retains only the extremely low static power consumption of the power management chip U1 and the hardware timer U2. Its standby leakage current can be reduced to the nanoamp level, thereby avoiding the problem of continuous microamp leakage in the traditional software hibernation mode and improving the system's ability to operate continuously in long-term dark environments.

[0054] Comparative Example 1

[0055] This comparative example presents a self-powered IoT node system without a gate control unit, the structure of which is as follows: Figure 1 As shown, it includes a light energy harvesting unit, an energy management unit, and a load unit connected in sequence.

[0056] The structure and function of the light energy harvesting unit are the same as those in Embodiment 1.

[0057] The structure and function of the energy management unit are basically the same as those in Embodiment 1, except that the energy management unit U1 is equipped with an energy storage status detection output terminal VBAT_OK, whose output threshold can be configured according to system requirements. When the energy storage voltage of the supercapacitor C1 reaches the preset operating threshold (e.g., 3.3V), the output terminal VBAT_OK outputs an effective level. The load unit includes a voltage regulator circuit U3 (such as HT7333-A), a microcontroller U4 (such as an nRF52840 module), a sensor module U5 (such as an SHT40 temperature and humidity sensor), and a wireless communication module integrated within the microcontroller U4. The power input terminal VIN of the voltage regulator circuit U3 is connected to the output terminal of the energy storage supercapacitor C1 to convert the operating voltage to a stable 3.3V. The power supply terminal of the sensor module U5 is connected to the output terminal of the voltage regulator circuit U3 and connected to the microcontroller U4 via an I2C bus to collect ambient temperature and humidity data and output it to the microcontroller U4. The wireless communication module is used to transmit ambient temperature and humidity data. The power supply terminal of the microcontroller U4 is connected to the output terminal VOUT of the voltage regulator circuit U3, and its D3 pin is connected to the VBAT_OK status output terminal of the energy management unit U1 to receive the energy storage status signal output by the energy management unit U1. When the energy storage voltage of the supercapacitor C1 reaches the preset operating threshold (e.g., 3.3V), VBAT_OK outputs a valid level. Based on this, the microcontroller U4 determines whether the current energy storage state meets the operating conditions for the wireless communication task, thereby avoiding high-power wireless transmission operations when energy storage is insufficient and improving the system's operational stability in low-light environments. The microcontroller U4 uses a traditional software sleep mode to achieve periodic wake-up and sleep control. During sleep, the voltage regulator circuit U3 remains continuously powered.

[0058] The load unit is also equipped with an output filter capacitor C2 (e.g., 100 μF), which is connected between the output terminal of the voltage regulator circuit U3 and ground. It is used to filter and store energy for the regulated output to alleviate voltage fluctuations caused by wireless communication or sensor startup and improve system operation stability. It belongs to the power filtering part of the load unit.

[0059] The operation process of the self-powered IoT node system proposed in this comparative example is as follows:

[0060] (1) Charging and energy accumulation stage

[0061] After system startup, the light energy harvesting unit continuously harvests ambient light energy in low-light indoor environments and charges the supercapacitor C1 via the energy management chip U1. The maximum power point tracking controller integrated within the energy management chip U1 optimizes the input energy to improve energy harvesting efficiency under low-light conditions. During the energy accumulation phase, the voltage regulator circuit U3 remains continuously conducting, supplying power to the microcontroller U4 and sensor module U5. At this time, the microcontroller U4 enters a software low-power sleep state, and the sensor module U5 enters a standby state to reduce system power consumption. However, the voltage regulator circuit U3 and the subsequent load circuits still continuously consume microamperes of static leakage current.

[0062] (2) Wake-up sampling phase:

[0063] When the energy storage voltage of the supercapacitor C1 reaches the preset operating threshold (3.3V), the voltage regulator circuit U3 outputs a stable operating voltage, and the microcontroller U4 exits sleep mode and resumes operation. The microcontroller U4 drives the sensor module U5 to collect ambient temperature and humidity data and sends the data to an external gateway or terminal device via a wireless communication protocol, then enters standby mode. It will be awakened to sample again in the next cycle.

[0064] (3) Standby phase:

[0065] After wireless transmission is complete, the system enters standby mode. At this time, the voltage regulator circuit U3 continues to output a stable operating voltage, the microcontroller U4 enters software sleep mode, and the sensor module U5 is in low-power standby mode to reduce system power consumption. However, because the system lacks a hardware-level gated power-off structure, the voltage regulator circuit U3, microcontroller U4, and sensor module U5 still experience microampere-level static leakage current. Therefore, in long-term dark environments, the system will continuously consume the stored energy in the supercapacitor C1, causing the stored energy voltage to gradually decrease. When the stored energy voltage falls below the normal operating voltage range of the microcontroller U4 or the wireless communication module, the system may experience wireless communication failures, malfunctions, repeated resets, or failure to function properly, thus affecting the long-term stable operation of the system.

[0066] The following section presents performance tests of the edge interconnect structure perovskite solar modules of Example 1 and Comparative Example 1, as well as system performance tests.

[0067] (I) Low-light power generation performance test of the perovskite solar modules with edge interconnect structure used in Example 1 and Comparative Example 1

[0068] The test results under low indoor illuminance conditions ranging from 250 lux to 1000 lux are as follows: Figure 4 As shown, Figure 4 (a) is the JV curve. Figure 4(b) shows the curve of spectral irradiance as a function of wavelength. To visually demonstrate the module (mask area: 2.1 cm²), 2 Table 1 details the core photoelectric parameters of the module under different illuminance levels, and shows its energy matching capability with the subsequent low-power circuit.

[0069] Table 1

[0070]

[0071] From Table 1 and Figure 4 It is evident that the 1.78 eV edge interconnect structure perovskite solar module exhibits excellent photoelectric performance in low-light environments. Even under extreme low-illuminance conditions of 250 lux, the open-circuit voltage provided by the front-end module still exceeds the 330 mV cold-start threshold required by the subsequent power management chip U1 by an order of magnitude, ensuring the system's self-starting capability in low-light environments. Simultaneously, under normal simulated illumination of 1000 lux, the module's total output power reaches approximately 240 μW; while under low illumination of 250 lux, the module can still provide a continuous output of approximately 58 μW. Combined with the nanowatt-level hardware power-off mechanism of Example 1, this is sufficient to support the system's low-frequency (e.g., once every 12 minutes) data reporting. This rigorously verifies the feasibility and excellence of the system architecture proposed in this example across a wide illumination range from a physical parameter perspective.

[0072] (II) Long-term stability test of the perovskite solar modules with edge interconnect structure used in Example 1 and Comparative Example 1

[0073] Figure 5 The normalized path current density Jsc, open-circuit voltage Voc, fill factor FF, and photoelectric conversion efficiency PCE of the edge interconnect structure perovskite solar modules in Comparative Example 1 and Example 1 under 86 days of continuous 1000 lux illumination aging are measured over time. The test results show that the Jsc, Voc, FF, and PCE of the edge interconnect structure perovskite solar module maintain high stability, with no significant degradation in PCE. This verifies that the edge interconnect structure can effectively suppress the diffusion of electrode metals (such as silver) into the perovskite functional layer, thereby slowing down device performance degradation and improving the long-term operational stability of the module.

[0074] (III) High-frequency operation power consumption test of the supercapacitor C1 in Example 1 and Comparative Example 1

[0075] To verify the energy-saving effect of the hardware timer U2 in actual deployment, the supercapacitor C1 (0.47 F) was first charged to near full charge using the indoor photovoltaic module and the subsequent energy management chip U1. Then, the solar energy input was cut off, allowing the system to operate independently without external energy supply. The system was set to wake up every 50 seconds to sense temperature and humidity, transmit wireless data, and continuously record the voltage across the supercapacitor C1. Figure 6 The graph shows a comparison of the voltage drop of the supercapacitor in Comparative Example 1 and Example 1 over time. The results show that in Comparative Example 1's 50-second broadcast cycle software sleep mode (blue curve, without TPL5110), the voltage of the supercapacitor C1 rapidly drops from 4.0 V to 2.19 V within 19.17 minutes. Based on the capacitor discharge equation I = C·∆V / ∆t, the overall average operating current is calculated to be 740 μA. In contrast, in Example 1 (pink curve, with TPL5110), because the hardware timer U2 cuts off the power supply path to the downstream load unit during the system sleep phase, significantly reducing the system's static leakage power consumption, the supercapacitor voltage drops from 3.86 V to 2.21 V within 112.33 minutes, thus reducing the overall average current to 115 μA. Therefore, compared to the traditional software sleep mode (Comparative Example 1), Example 1 significantly reduces the average power consumption during the system standby phase through a hardware-level gated power-off mechanism, resulting in a significantly slower rate of voltage drop in the supercapacitor. Even under high-frequency broadcast cycle conditions, the system can still maintain a relatively stable energy storage voltage output, thereby reducing the risk of wireless communication failure, system reset or abnormal operation caused by insufficient energy storage, and improving the system's long-term stable operation capability in low-light environments.

[0076] (iv) Practical application verification of the system proposed in Example 1 and Comparative Example 1

[0077] To simulate the circadian rhythm of lighting in a real indoor office environment, the experimental conditions were set as follows: alternating cycles of 12 hours of 1000 lux illumination and 12 hours of 0 lux (complete darkness). The system was woken up every 12 minutes to collect temperature and humidity data and transmit wirelessly. Before the test began, the supercapacitor C1 was fully charged.

[0078] Figure 7 The indoor temperature and humidity change curves are periodically collected in a real deployment scenario for the systems proposed in Comparative Example 1 and Example 1. Figure 7 (a) is the system data for Comparative Example 1. Figure 7 (a) is the system data for Comparative Example 1.

[0079] according to Figure 7As shown in (a), the system in Comparative Example 1 only successfully completed about two cycles of data acquisition and wireless transmission. Subsequently, due to insufficient energy storage in the supercapacitor, the system gradually experienced wireless communication failures, microcontroller resets, and even failure to continue working.

[0080] Combination Figure 5 It can be seen that after configuring the hardware timer TPL5110 in Example 1, the power supply path to the downstream load can be cut off through hardware gating during the standby phase. Therefore, the 625 μA current difference between Comparative Example 1 (740 μA) and Example 1 (115 μA) can be approximated as the static current consumption generated by the continuous power supply of the downstream in the traditional software sleep mode. If estimated based on the average system operating voltage of approximately 2.6 V, the static leakage power consumption of Comparative Example 1 is approximately: P = VI = 2.6 V * 625 μA ≈ 1625 μW. However, under experimental conditions, the photovoltaic input power is only about 240 μW. Therefore, the system of Comparative Example 1 is in a long-term energy deficit state, that is, the system power consumption is much higher than the ambient input power. At this time, the net power consumption of the system is approximately: P loss =1625−240=1385 μW =1.385 * 10 -3 J / s. At this time, the energy stored in the supercapacitor C1 will be continuously consumed, and its release energy can be estimated by the capacitor energy storage formula: E=0.5*C(V1) 2 - V2 2 Where C = 0.47 F, V1 = 4.0 V, V2 = 2.6 V, the calculated energy that the supercapacitor C1 can release is approximately: E = 0.5 * 0.47 (42 - 2.62) ≈ 2.17 J. Therefore, without considering the instantaneous power consumption of active sampling and wireless transmission, the theoretical energy storage duration of the system in Comparative Example 1 due to standby leakage is approximately: T = 2.17 J / (1.385 * 10⁻⁶). -3 J / s ≈ 26.1 min.

[0081] The above estimation results are consistent with Figure 7 The experimental phenomena in (a) are basically consistent, indicating that when the hardware-level gated power-off structure is not configured, the downstream voltage regulator circuit and load unit still have continuous static leakage current in the standby stage, which leads to a continuous decrease in the energy storage of the supercapacitor and is prone to problems such as abnormal system operation, wireless communication failure or microcontroller reset under long-term dark or weak light conditions.

[0082] according to Figure 7As shown in (b), the system of Example 1 can operate stably for more than 4 days without data loss. Even during the 12-hour dark nighttime period, thanks to the hardware-level gated power-off mechanism proposed in Example 1, which physically cuts off the leakage power supply path of the downstream voltage regulator circuit and load unit, the system consumes only a very small amount of stored energy in the supercapacitor during standby, thus effectively avoiding the problem of energy depletion caused by continuous leakage in traditional software hibernation nodes at night. When sunlight resumes the next day, the edge interconnect structure perovskite photovoltaic module can continuously provide energy input to the system and quickly replenish the energy in the supercapacitor, achieving stable power supply to the system.

[0083] Experimental results show that the system proposed in Example 1 achieved 100% data online rate during multiple day-night cycles, without any communication interruptions, system resets, or node failures. These results fully verify that the proposed hardware-gated self-powered architecture possesses excellent stability and continuous operation capability in long-term low-light environments, meeting the practical deployment requirements of all-weather, maintenance-free IoT nodes.

[0084] It should be noted that this is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A long-lasting self-powered Internet of Things (IoT) node system for low-light environments, characterized in that, It includes a light energy harvesting unit, an energy management unit, a gating control unit, and a load unit connected in sequence; The light energy harvesting unit is used to harvest ambient light in low-light environments and output photovoltaic voltage; The energy management unit is used to boost the photovoltaic voltage to the operating voltage and store energy. The gate control unit is used to control the power supply to and from the load unit, and specifically includes a drive end, a feedback signal receiving end, and a power input end. The power input end is connected to the energy management unit. When the energy storage voltage of the energy management unit reaches the operating voltage of the gate control unit, it triggers the gate control unit to complete the power supply to enable the load unit to enter the wake-up period. The load unit includes a voltage regulator circuit, a sensor module, and a microcontroller. The voltage regulator circuit is connected to the drive terminal of the gate control unit to convert the operating voltage into a stable voltage. The power supply terminal of the sensor module is connected to the output terminal of the voltage regulator circuit, and the communication terminal is connected to the microcontroller to collect target data and transmit it to the microcontroller. The power supply terminal of the microcontroller is connected to the output terminal of the voltage regulator circuit, and the feedback terminal is connected to the feedback signal receiving terminal of the gate control unit to send a feedback signal to the gate control unit after completing the target data processing or transmission, thereby triggering the gate control unit to complete the power supply shutdown and put the load unit into a sleep state.

2. The long-lasting self-powered IoT node system in low-light environments according to claim 1, characterized in that, The gate control unit is designed based on a hardware timer and controls the periodic wake-up sampling time interval by configuring the timing period control system.

3. The long-lasting self-powered IoT node system in low-light environments according to claim 2, characterized in that, The load unit also includes a communication module, which is used to send target data to an external terminal or gateway device, and trigger the microcontroller to send a feedback signal to the gate control unit after the transmission is completed.

4. The long-lasting self-powered IoT node system in low-light environments according to claim 2, characterized in that, The sensor module is at least one of an environmental sensor, a microampere-level current detection sensor, and a biochemical detection sensor.

5. The long-lasting self-powered IoT node system in low-light environments according to claim 2, characterized in that, The energy management unit includes a boost converter with cold start function and an energy storage capacitor; wherein, the boost converter is used to boost the photovoltaic voltage to the operating voltage; and the energy storage capacitor is used to store energy at the operating voltage.

6. The long-lasting self-powered IoT node system in low-light environments according to claim 5, characterized in that, The energy management unit also includes a maximum power point tracking controller integrated with the boost converter, used to dynamically adjust the input impedance of the boost converter to match the maximum power point of the light energy harvesting unit.

7. The long-lasting self-powered IoT node system in low-light environments according to claim 5 or 6, characterized in that, The solar energy harvesting unit includes multiple sub-cells connected in series, the number of which is configured such that the output photovoltaic voltage is greater than the cold start threshold voltage of the boost converter.

8. The long-lasting self-powered IoT node system in low-light environments according to claim 7, characterized in that, The effective light-receiving area of ​​the light energy acquisition unit is configured such that its output power in a low-light environment is greater than the average power consumption of the system during periodic operation. The average power consumption during periodic operation is the average of the data acquisition and transmission power consumption of the load unit during the wake-up period and the static leakage power consumption during the sleep period.

9. The long-lasting self-powered IoT node system in low-light environments according to claim 2, characterized in that, The load unit is also equipped with an output filtering and feedback protection circuit, specifically including a first capacitor, a resistor, and a second capacitor. The first capacitor is connected between the output terminal of the voltage regulator circuit and ground to filter and store energy for the stable voltage. The resistor is connected in series between the feedback terminal of the microcontroller and the feedback signal receiving terminal of the gate control unit to limit the feedback pulse current, protect the feedback terminal interface, and improve the stability of the feedback signal transmission. The second capacitor is connected between the feedback signal receiving terminal of the gate control unit and ground to debouncing and transient filtering the feedback signal to prevent noise interference from causing the gate control unit to be falsely triggered and shut down.

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