Design of terminal nodes for small and medium scale intelligent agriculture Internet of Things

Internet of Things (IoT) technology has been increasingly used in agriculture. However, most existing agricultural IoT technologies are focused on providing management and service applications to large scale agriculture. In order to provide customized agricultural IoT technology to small and medium scale agricultural producers and operators, an intelligent agricultural IoT terminal node can be used for flexible information upgrade of agricultural equipments and other related devices was designed in this study. The system consisted of terminal nodes and management/service layer App. Through a terminal node, agricultural equipments and other related devices could be flexibly connected to agriculture IoT information frameworks. The management/service layer App linked to terminal node hardware and support the rapid and low-cost development. In the hardware device layer of the system, the IP core reuse technology of system on programmable chip (PSoC) was used to realize the flexible adaptation and access to various agricultural equipments and other related device. The PSoC of terminal node was designed on Cypress's PSoC 6 (PSoC6-CY8CPROTO-063-BLE). The long-range low-power wide-area network (LoRa LPWAN) technology was adopted in the system to build data transmission channels between terminal nodes, and the LoRa in terminal node was designed on LoRa wireless communication module based on Semtech's SX1278. The nodes use low-power Bluetooth technology to enable mobile smart devices (e.g., smartphones, tablets, etc.) to access the terminal nodes and achieve distributed agriculture management, and the Bluetooth on the terminal node was based on the integrated Bluetooth module in the PSoC6. The management/service layer App encapsulated the operation of the underlying terminal node and Android functions. Android Content Provider component combined with SQLite database was used to realize the mapping relationship between different layers. The introduction of the management/service App made the development of application-layer App faster and more suitable for the diversified needs of agricultural IoT requirements. The system was tested in different agricultural application scenarios. The results showed that terminal nodes could effectively provide information upgrade to agricultural equipment and related devices through IP-core reuse technology, and the electromagnetic isolation capacity of the system reached 1 500 VDC, the success rate of data packet transmission of Lora wireless data channel of node was close to 100% in the weather without severe rainfall, and Bluetooth could support the mobile device field access within 3 m around, in the mode of directly connected upper computer, the function delay between application layer App and node equipment was less than 400 and 1 700 ms respectively, the system ran stably and the function support was reliable. This study can provide support and reference for the information construction of Internet of Things for small and medium scale agricultural operators.