Apogee S2-411-SS SDI-12 upward-looking NDVI sensor

Product detailed description

Stop relying only on visual estimates and get accurate, objective data on the health and vitality of your plants. The Apogee S2-411-SS NDVI sensor provides you with key information for optimising watering, fertilisation and overall care, leading to a richer and higher-quality harvest.

Key features

• Accurate NDVI calculation: Provides a reliable indicator of plant health and canopy density.
• Extreme durability: Fully waterproof and submersible aluminium housing with IP68 protection can handle even the most demanding outdoor conditions.
• Easy integration: The standard SDI-12 digital protocol ensures seamless connection to modern dataloggers and control systems.
• High stability and reliability: Minimal long-term drift guarantees consistent and repeatable measurements for years.
• Designed for continuous operation: Robust construction and high-quality cabling are made for permanent outdoor installations.

Accurate measurement for plant health

The sensor works on the principle of measuring reflected sunlight at two specific wavelengths: 650 nm (red light) and 810 nm (near-infrared light, NIR). Healthy plants with a high chlorophyll content intensely absorb red light for photosynthesis, while they reflect near-infrared light. From the ratio of these two values, the sensor calculates the normalised difference vegetation index (NDVI).

The NDVI value is closely related to the amount of chlorophyll in the leaves and the overall leaf area of the canopy. This gives you an accurate picture of the vitality, density and health status of your annual plants, tomatoes, herbs or any other crops. The stability and accuracy of the measurements allow you to identify stress factors in time and respond to them effectively.

Extreme durability and easy integration

This sensor is designed for long-term and reliable operation in the field. Its body consists of a robust, fully potted aluminium housing with IP68 protection rating, which means it is completely dust-tight and can withstand even permanent immersion in water. You therefore do not need to worry about rain, high humidity or demanding conditions during outdoor growing.

Communication takes place via the standard SDI-12 digital protocol, which makes it easy to connect to a wide range of logging and control units. The five-metre cable is terminated with a high-quality stainless steel connector (marine-grade), which not only resists corrosion, but also allows easy disconnection of the sensor for maintenance or calibration without the need for complicated dismantling.

Wide range of uses

Whether you are an advanced home grower, a small farm, or a researcher, this sensor will open up new possibilities for monitoring and optimisation. Typical applications include:

• Monitoring the density and overall health of annual plants.
• Monitoring seasonal changes, such as spring green-up and autumn senescence.
• Optimising fertiliser doses based on the actual needs of plants.
• Phenological studies and monitoring plant development stages.
• Early detection of stress caused by drought, pests or diseases.
• Assessing the impact of agronomic interventions and many other scientific and commercial applications.

Technical specification

• Output: SDI-12 digital protocol
• Power supply: 5.5 to 16 V DC
• Current draw: 1.1 mA (idle), 2.2 mA (active)
• Calibration uncertainty: ± 5 %
• Measurement repeatability: Less than 0.5 %
• Long-term drift (instability): Less than 2 % per year
• Response time: Less than 1 second
• Field of view: 180° (hemispherical)
• Spectral range: 650 nm (20 nm bandwidth); 810 nm (20 nm bandwidth)
• Operating environment: -40 to 70 °C; 0 to 100 % relative humidity
• Dimensions: diameter 2.4 cm, height 3.7 cm
• Weight: 140 g
• Cable: 5 m of shielded twisted pair conductors with TPE sheath and stainless steel connector
• Protection: IP68
• Warranty: 4 years