Development of solar-powered crop light-supply system

In crop growth, light conditions have important effects on the growth rate, yield, and quality of crops [1, 2]. At present, most of China’s facility agriculture still relies on incandescent lamps, tungsten halogen lamps, high-pressure mercury-fluorescent lamps, and high-pressure sodium lamps as light sources to supplement plants [3 - 4]. These traditional methods of supplementing light have unsatisfactory spectral matching [5]. - 6]. Low utilization of light energy and failure to consider the impact of other environmental factors. The high energy consumption makes it difficult to form a high input-output ratio in actual production. With the development of semiconductor technology, the use of LED cold light sources as the light source for the supplemental light has also been proposed [7], which can solve the problem of the above-mentioned fill light source to some extent. However, due to the fact that most R&D projects and products still use fixed light and fixed light, they do not take into account the differences in the amount of light required at different stages of different plants, resulting in insufficient co-existence of insufficient light and excessive light. Solve the problem of low energy consumption and precise fill light [8].

To solve the above problem, we developed a smart, precise, energy-efficient supplemental lighting system that fully consider the impact of different plants in different environments at different stages of the required amount of light fill light. Based on sub-band light intensity detection technology, intelligent control technology and other modern electronic information technology, STC12C5A60S2 single-chip microcomputer is used as the core processor [9], and PT4115 is the LED drive module [10]. Based on the results of temperature and light intensity detection, various types of plants are realized. In the appropriate environment, sub-wavelength quantitative fill light on demand. Under the premise of satisfying the light required for its growth, it maximizes the utilization of output light energy, has the characteristics of low error, fast response, low cost, and simple maintenance.

The system adopts a modular design and is divided into a power module, a detection module, a control module, a fill light module, and a user interaction module. The overall structure is shown in FIG. Among them, the power module uses solar power to provide two kinds of supply voltages, 5V and 12V, respectively, to supply power for the entire system. The intelligent control module uses STC series microcontrollers as the core. According to the data collected by the system and setting the threshold, the corresponding PWM control signals can be realized. Duty cycle calculation and two PWM control signal output; Detection module sub-band detection of red, blue light and real-time temperature, and the detection signal is filtered, amplified, and then transferred to the microcontroller, to achieve the detection of relevant environmental information; Fill light module uses two The constant current drive circuit with PWM current control function controls the brightness of the red and blue LED fill light array lamps respectively to achieve accurate quantitative light fill; the user interaction module uses the LCD screen to complete the test result display, and the keyboard implements on-demand threshold modification. Other functions, complete the threshold modification and setting, effectively improve the convenience and scalability of the system.

2. 1 Power Module

The power supply module of this system is composed of solar panels, storage batteries and control circuits. The entire system is powered by solar cells. The schematic diagram is shown in Figure 2. Among them, the input end of the control circuit is connected with the solar battery, the input voltage charges the 12V battery through the LM317 and its peripheral standard circuit, and the battery supplies power for the whole system. The battery output uses the MIC29302 regulated voltage transformer module to output a 12V regulated power supply signal, and adjusts the matching resistor to generate a 5V regulated power supply signal, thus providing the system with 12V and 5V power supplies. Among them, the one-chip computer, detection module and user interaction module all use 5V power to supply power, LED fills the light module and uses 12V power to supply power.

Figure 1, power module schematic

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