A Small Flying IoT Node for Real-Time Spectral Monitoring in Smart Agriculture

The rapid advancement of Internet of Things (IoT) technologies is driving a paradigm shift in smart agriculture. Spectrometers play a crucial role in modern agriculture and, when integrated with robotic mobile platforms such as nano-drones, enable flexible, precise, and cost-effective monitoring of crops and greenhouses. However, until recently, spectrometers were bulky and heavy, preventing their integration into small flying platforms due to weight constraints. In this work, we leverage the latest generation of mini-spectrometers to introduce, for the first time, a nano Unmanned Aerial Vehicle (UAV)-based smart sensor node capable of real-time spectral data sampling and processing. To achieve this, we designed a lightweight sensor shield featuring the C12880MA mini-spectrometer from Hamamatsu Photonics (2.53 cm³, spectral range 340–850 nm), compatible with a small and lightweight (27 g, 10 cm diameter) commercially available nano-drone from Bitcraze. With a total flight mass of 46.26 g, the system remains highly maneuverable and particularly well-suited for confined spaces. Our results show that spectral data can be sampled at 14.32 Hz and with a power consumption of approximately 94 mW. The system was validated for detection of green/red portions during flight, simulating a method to distinguish zones within a greenhouse with ripe and unripe tomatoes (which can be extended to other use-case scenarios), achieving an accuracy of above 95% while providing about 6 minutes of flight time.