Apogee PAR Smart Sensors

Solar Radiation

The SQ-420 & SQ-520 can be used two ways - they can be connected to a computer for real-time measurements using the provided software, or when simply connected to a power source, can act as a stand-alone datalogger capable of storing 10,000 measurements internally that can then be uploaded to a computer for analysis.


  • Used to measure incoming and reflected PPFD around plants and other organisms in outdoor environments, greenhouses, growth chambers, and underwater.
  • The sensor has internal data storage capability with the ability to hold up to 10,000 measurements. This allows the sensor to collect data while connected to a stand-alone 5 V DC power supply such as an independent battery pack or USB wall adapter.
  • No datalogger required. The sensor can be connected to a desktop, laptop, or tablet computer via USB 2.0 type A plug to be used with the Apogee software.
  • The included Apogee software gives the user control of data logging and calibration settings, provides a real time output display and graph of PPFD measurements and allows the data set to be saved as a csv file.
  • The SQ-420 is calibrated independently for sunlight and electric light to improve measurement accuracy. The light source calibration can be selected in the settings menu of the Apogee software.
  • The SQ-520 has an enhanced spectral response making it suitable for both sunlight and electric light.
  • Resolution: 0.1 µmol m-2 s-1
  • Response Time:software updates every second
  • Field of View:180°
  • Can be submerged in water up to depths of 30 m
  • Memory: 10,000 measurements



Leveling Bases

The AL-100 is required for sensors on cable.

AL-100 Solar Sensor Leveling Plate
Mounting Brackets

The AM-110 fits the AL-100 leveling base and can be mounted directly to a mast or pipe with an outer diameter of 33-53 mm.

AM-110 Solar Sensor Mounting Bracket


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SQ-420 Specifications

File Size 830KB   Filename sq-420-spec-sheet.pdf   Download

SQ-520 Specifications

File Size 906KB   Filename sq-520-spec-sheet.pdf   Download

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