The perception layer gathers real‑time data from the growing environment. Key sensors include photodetectors for light intensity and spectrum, digital hygrometers for temperature and relative humidity, and CO₂ sensors. More advanced systems may also incorporate pH and electrical conductivity (EC) sensors for hydroponic nutrient solutions.
For instance, a photosynthetic photon flux density (PPFD) sensor placed at canopy height continuously measures the actual light the plants receive. If natural sunlight suddenly increases through greenhouse glazing, the sensor detects the rise and signals the controller to dim the LEDs accordingly, preventing over‑lighting and saving energy. This closed‑loop sensing is the foundation of any intelligent plant lighting system.
