Powerful Tools That Illuminate Your Insights
Light monitoring is the process of measuring light levels and exposure over time so you can understand how changing conditions affect plants, aquatic environments, buildings, collections, and equipment. Unlike a single spot reading, time-stamped measurements reveal daily patterns, seasonal changes, and short-duration events that might otherwise go unnoticed.
The right light measurement depends on your application. Photosynthetically active radiation (PAR) measures photons in the 400–700 nm waveband used in photosynthesis, while global solar radiation measures incoming solar energy across a broader waveband in watts per square meter. For indoor applications, light intensity and light on/off data can help document operating schedules, exposure, and building use.
HOBO and LI-COR solutions make it easier to collect dependable light data in greenhouses, farms, aquatic environments, research sites, museums, offices, and other indoor spaces. Choose from stand-alone data loggers, plug-and-play smart sensors, wireless HOBOnet sensors, and compatible LI-COR sensors to match your measurement, environment, and data-access needs.
A Spectrum of Light Sensor Options
Photosynthetically Active Radiation (PAR)
Measure the light available for photosynthesis in greenhouse, crop, canopy, and aquatic research applications.
Global Solar Radiation
Track direct and diffuse solar energy for agricultural, environmental research, and weather monitoring applications.
Underwater PAR
Monitor PAR, water temperature, and sensor tilt below the surface, with convenient Bluetooth data offload.
Indoor Light Monitoring
Track relative light intensity and light on/off conditions to document lighting schedules, exposure, and building use.
PAR Data Loggers for Agricultural and Underwater Environments
PAR, Temperature, RH, DLI & VPD Data—From One Logger
The HOBO MX2308 Temp/RH/PAR Data Logger combines a LI-COR quantum sensor with temperature and relative humidity monitoring, helping growers and researchers connect changing light conditions with the surrounding environment.
- Measures PAR from 0 to 3,000 µmol/m²/s across the 400–700 nm waveband
- Provides calculated accumulated PAR, daily light integral (DLI), vapor pressure deficit (VPD), and dew point
- Offloads data wirelessly to the HOBOconnect app from approximately 100 feet away under line-of-sight conditions
- Features an IP67-rated enclosure for use in demanding outdoor environments
Underwater PAR, Temperature & Tilt—Wireless Offload
The HOBO MX2502 Underwater PAR Data Logger combines a LI-COR underwater quantum sensor with temperature, tilt, and water-detection measurements for aquatic research in fresh or salt water.
- Measures underwater PAR from 0 to 3,000 µmol/m²/s across the 400–700 nm waveband
- Includes separate calibration factors for measurements in water and air
- Records temperature, sensor tilt, and water detection to provide additional deployment context
- Offloads data wirelessly to the HOBOconnect app without opening the logger
- Features an IP68-rated enclosure for deployments up to 30 meters in non-freezing water
Photosynthetically Active Radiation (PAR) Sensors
Global Solar Radiation Sensors
The Fundamentals of Light Measurement
How Do You Measure Light?
Different light sensors respond to different portions of the spectrum, so the right measurement depends on the question you need to answer. The diagram compares three common approaches:
- Photometric sensors measure visible light based on human visual response for applications such as indoor lighting.
- Quantum sensors measure photosynthetically active radiation (PAR) from 400–700 nm in µmol/m²/s for plant and aquatic research.
- Pyranometers measure global solar radiation across a broader waveband in W/m² for weather, agricultural, and solar energy applications.
Light Sensor Design
LI-COR light sensors incorporate design features that support dependable measurements in field conditions. A water-shedding crown helps prevent moisture from collecting on the sensor, while the sensor’s cosine-corrected response accounts for radiation arriving from different angles.
Photodiodes and optical filters define the sensor’s spectral response. Interchangeable sensor heads, detachable bases, and multiple output options provide flexibility for different monitoring systems and service requirements.
Connect Your Sensors to a Remote Monitoring Network
Connect HOBOnet wireless light sensors to a compatible HOBO RX station to create a flexible remote monitoring network. Measurements are automatically transmitted to LI-COR Cloud, helping you review current conditions and long-term trends without traveling to every sensor location.
- Connect up to 50 wireless sensors to a HOBOnet network
- Review measurements remotely through customizable LI-COR Cloud dashboards
- Configure threshold notifications for changing or out-of-range conditions
- Reduce manual site visits while maintaining access to current monitoring data
Bare-lead LI-COR light sensors can also be incorporated into compatible RX systems using the appropriate 2420-BL interface and Analog Mote or Analog Module.
Looking for Indoor Light Monitoring?
For indoor applications, HOBO data loggers can help document relative light intensity and verify when lights turn on and off. Use time-stamped light data to evaluate operating schedules, investigate unnecessary lighting, assess exposure around sensitive materials, and add context to occupancy or energy studies.
Select the logger and measurement range that fit your application, then review the results alongside temperature, relative humidity, occupancy, or other building conditions when a more complete environmental picture is needed.
Frequently Asked Questions (FAQs)
Light Measurement Resources
Introduction to the MX2308 Temp/RH/PAR Data Logger
Learn how the MX2308 combines PAR, temperature, and relative humidity measurements with calculated DLI and VPD data for greenhouse, agricultural, and environmental research.
Watch NowSmarter Greenhouses & Indoor Farms: Monitoring Strategies for Year-Round Productivity
Explore how PAR, DLI, solar radiation, temperature, relative humidity, soil moisture, and electrical conductivity data can support monitoring in greenhouses and indoor farms.
Watch NowSeamless Light Monitoring with the New HOBO Underwater PAR Data Logger
Learn why underwater PAR measurements matter, what can affect light below the surface, and how the MX2502 supports freshwater and marine monitoring.
Watch Now