Apogee S2-411-SS SDI-12 Upward-Looking NDVI Sensor

Stop relying on visual guesswork and get accurate, objective data on the health and vigour of your plants. The Apogee S2-411-SS NDVI sensor provides you with key information to optimize watering, fertilizing and overall care, resulting in a richer, better quality crop.

Key Features

• Accurate NDVI calculation: provides a reliable indicator of plant health and density.
• Extreme durability.
• Easy integration: the standard SDI-12 digital protocol ensures seamless connection to modern data loggers and control systems.
• Minimal long-term drift ensures consistent and repeatable measurements for years.
• Designed for continuous operation.

Accurate measurements for plant health

The sensor works on the principle of measuring reflected sunlight in two specific wavelengths: 650 nm (red light) and 810 nm (near infrared light, NIR). Healthy plants with high chlorophyll content intensively absorb red light for photosynthesis, while reflecting near infrared light. From the ratio of these two values, the sensor calculates the Normalized Difference Vegetation Index (NDVI).

The NDVI value is closely related to the amount of chlorophyll in the leaves and the total leaf area of the stand. This gives you an accurate picture of the vigour, density and health of your annuals, tomatoes, herbs or any other crop. The stability and accuracy of the measurements allow you to identify stress factors early and respond effectively.

Extreme durability and easy integration

This sensor is designed for long-term and reliable operation in the field. Its body consists of a rugged, fully encapsulated aluminum housing with IP68 certification, which means it is completely dustproof and can withstand permanent immersion in water. So you don't have to worry about rain, high humidity or the harsh conditions of outdoor growing.

Communication is via the standard SDI-12 digital protocol, which makes it easy to connect to a wide range of recording and control units. The five meter cable is terminated with a high quality marine-grade stainless steel connector that not only resists corrosion, but also allows the sensor to be easily disconnected for maintenance or calibration without the need for complicated disassembly.

Wide range of applications

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

• Monitoring density and overall stand health of annual plants.
• Monitoring seasonal changes such as spring greening and fall senescence.
• Optimization of fertilizer rates based on actual plant needs.
• Phenological studies and monitoring of plant developmental stages.
• Early detection of drought, pest or disease stress.
• Impact assessment of agronomic interventions and many other scientific and commercial applications.

Technical specifications

• Output.
• Power supply: 5.5 to 16 V DC
• Current draw: 1.1 mA (quiescent), 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 shielded twisted pair wire with TPE jacket and stainless steel connector
• Protection: IP68
• Warranty: 4 years