Abstract:
In the realm of the Internet of Things, humidity monitoring is imperative for the progressive evolution of intelligent technology within the domains of healthcare, agriculture, and industry. Herein, a resistive-type, multifunctional, and highly sensitive gold-nanoparticle-based humidity sensor was developed, which has a whopping ∼5 orders of resistance change in response to humidity variation from 40%RH to 95%RH. The sensor exhibits excellent sensitivity (28.6 MΩ/%RH), high thermal stability (in the usual working temperature range 25–50 °C), high flexibility (under different bending radii from 18 to 24 mm), prolonged shelf life (∼190 days), and short response/recovery time (∼206/∼280 ms toward respiration monitoring). Owing to these merits, the fabricated sensor has been illustrated for applications like respiration monitoring, non-contact sensing, and soil moisture monitoring. Furthermore, we have designed and demonstrated a smart irrigation system by integrating the gold-nanoparticle-based non-contact humidity sensor for the first time with an Arduino microcontroller. This device is designed to continually observe the soil moisture level using a calibration algorithm that monitors the humidity and supplies water to the crop plant according to a preset threshold. This helps in intelligent assessment and response to the moisture content of the soil in real time.
