Self-powered flexible sensor network for continuous monitoring of crop micro-environment and growth states

•The two-layer wireless sensor network can monitor plant micro-environment.•Sensor nodes with polyimide substrates are arranged on crops’ leaves and stems.•The power consumption of the master and sensor nodes is as low as 6 mW and 132 μW.•The solar energy harvesting system makes the sensor network self-powered. Monitoring crops’ micro-environment and growth states is significant for developing smart agriculture. However, the traditional rigid and large-sized sensor systems cannot meet the demands of precision agriculture for multi-parameter and high-throughput monitoring. Here, we integrate a flexible sensor system with low-power communication techniques, designing a two-layer star topology sensor network based on BLE and NB-IoT protocol. The sensors are arranged on flexible substrates, allowing them to closely adhere to various parts of crops, such as stems and leaves. To ensure the accuracy of the sensors, they are evaluated and calibrated in the laboratory. A solar energy harvesting system is designed for the sensor network to make it self-powered and successfully measure temperature, humidity, illumination, and leaf angles stably, demonstrating the system’s feasibility. The deployment cost of the sensor network is significantly lower than that of traditional automatic weather stations, showcasing its potential for widespread application in farmlands.