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Enabling better global research outcomes in soil, plant & environmental monitoring.


The SNiP-DPS is a 'Sensor Node Integrated Package' for LoRaWAN or CAT-M1 communication of real-time plant diameter measurements for continuous plant monitoring.


The base SNiP-DPS integrates 1x S-NODE and 1x DPS40 Pivot Stem Dendrometer soil moisture sensor (previously the Decagon MPS-6) to a site’s unique network, communication and power requirements. The S-NODE can support an added 3x DPS40 Pivot Stem Dendrometer devices.

The DPS40 Pivot Stem Dendrometer is an SDI-12 Band Dendrometer designed to measure short- and long-term changes in stem circumference.


See Further Specifications on the S-NODE
See Further Specifications on the DPS40 Pivot Stem Dendrometer

Further parameters can be added to the SNiP, without requiring loggers to match each distinct sensor, substantially reducing the cost of getting a fuller picture on the application. The S-NODE can support 3x additional DPS40 Band Dendrometers or 3x other SDI-12 sensors to the base package.

See other IoT Nodes to include further sensor extensions in a custom Sensor-Node IoT Package.

The DPS40 features SDI-12 output for compatibility with a range of data logging solutions.

The DPS40 is also available with voltage output (DPV40).

Installation notes:
Sensor has to be placed on a relatively straight and regularly shaped stem (or branch) such that the plastic cover of the electronics does not touch the measured object. The cable has to be fastened to the stem in order to avoid its influence on the sensor position. The label on the black plate on the jib must be visible – it must point outwards of the stem.


The S-NODE (for Environmental Monitoring) has been designed to support the broad suite of SDI-12 based environmental sensors. The S-NODE can support sensors with higher power requirements; a solar panel can charge either the internal lithium-ion battery or both the node and sensor can be powered by an external 12V system (e.g. battery or mains source).

A decoder suitable for TTN will be provided based upon sensor configuration.

  • LoRaWAN™ low-power long-range connectivity
  • Supports the full range of SDI-12 commands, and sensors requiring constant excitation.
  • Optional CAT-M1
  • Solar rechargeable Lithium-ion, Single use LiSOCl2, or external 12V power options
  • Optional Multi-constellation GNSS
  • AS923, AU915 and US915 available, with other region plans available upon request.
  • Standard IP65 enclosure, optional IP67


DPS40 SDI-12 Pivot Stem Dendrometer

The DPS40 SDI-12 Pivot Stem Dendrometer is designed for the measurement of the diameter of small stems or branches between 5mm and 40mm. Sensor output is calibrated directly in millimetres of stem diameter.

The sensor is designed with respect to easy and fast installation. It is fastened on the measured object by three pressure levers; the central jib turns the rotary position sensor proportionally to the object diameter. Adherence pressure is set as a compromise between the influence on plant tissues and installation stability. The bearing of the position sensor is carefully shaped for minimal effect of temperature and axial forces.

Each sensor is individually calibrated in 100 points over the whole range for excellent sensor linearity.

  • Pivot-based sensing
  • Sensors are individually calibrated in mm of diameter
  • Step-less reading
  • Easy and fast non-invasive fixing
  • Good thermal properties prevent a temperature effect on measurement
  • SDI-12 or Voltage output options
  • SDI-12 output is individually calibrated to 100 points for excellent linearity

SDI-12 output is ideal for use with the ICT International SDI-12 Logger or the S-NODE.

Measurement Range: 5 to 40mm
Accuracy: > 0.5mm
Linearity: ± 0.5% of full scale
Resolution: 1.24 µm
Input Voltage: 5 to 12V DC
Current Consumption (Idle): 20 µA
Current Consumption (During Measurement): 6 mA
Tightening Strength: 1.5 to 2N lateral levers, 2 to 3N central sensing jib
Temperature Measurement Accuracy: ±0.2°C
Operating Environment: -40 to 60°C
Warm-up Time: 300 ms
Connection: Three wire Escha M8 connector (male)
Mass: 150g
Protection: IP67