Apogee S2-412-SS Downward-Looking SDI-12 NDVI Sensor

Get accurate data on the health of your stand

The S2-412-SS sensor is the ultimate tool for accurate measurement of plant health and density. Using the Normalized Difference Vegetation Index (NDVI), you get objective data that is crucial for precision agriculture, scientific research and advanced vegetation monitoring, including challenging annual plants.

How does the sensor work?

The sensor measures reflected solar radiation in two specific bands: red (Red, 650 nm) and near-infrared (NIR, 810 nm). Healthy, vigorous plants with high chlorophyll content absorb most of the red light for photosynthesis and strongly reflect near-infrared light.

From these two values, the sensor calculates the NDVI index using the formula (NIR - Red) / (NIR + Red). A high NDVI value indicates dense and healthy vegetation, while low values may indicate plant stress, pest infestation, disease or nutrient deficiency.

Key features and benefits

• Accurate NDVI measurement: you get objective data to make informed decisions about irrigation, fertilisation or plant protection.
• SDI-12 digital output: standardized protocol ensures easy integration with data loggers and control systems.
• Extreme durability.
• Self-cleaning design.
• Low power consumption: with a current draw of only 1.3 mA, the sensor is ideal for long-term field installations powered by batteries or solar panels.
• Four-year warranty: warranty against defects in materials and workmanship is proof of high quality and reliability.

Typical sensor applications

This sensor is an invaluable tool for a wide range of applications. In agriculture, it allows you to monitor the condition of crops such as tomatoes, peppers or strawberries and to optimise agronomic interventions. In research, it is used to monitor phenological phases (germination in spring, senescence in autumn), assess drought impacts, ecosystem research, leaf area estimation (LAI) and many other purposes.

Parameters

• Output: Digital, SDI-12 v1.3 protocol
• Input voltage: 4.5 to 28 VDC
• Current draw: 1.1 mA (quiescent), 1.3 mA (active)
• Response time: < 1 s
• Field of View (FOV): 32.2° (downward facing)
• Measured wavebands: 650 nm (20 nm wide), 810 nm (20 nm wide)
• Calibration uncertainty: ± 10%
• Measurement repeatability: < 1 %
• Long-term drift: < 2 % per year
• Operating environment: temperature -40 to 70 °C, relative humidity 0 to 100 %
• Dimensions: diameter 2.4 cm, height 2.75 cm
• Weight: 100 g (including 5 m cable)
• Cable: 5 m shielded twisted pair, Santoprene jacket, stainless steel connector
• Protection: IP68
• Warranty: 4 years