DD-RO Diameter Dendrometer Root/Underwater

The DD-RO series dendrometer is used for the high-precision and continuous measurement of plant diameter changes. This device is suitable for long-term application in outdoor conditions (underground and underwater). Due to their extremely low power consumption, Ecomatik dendrometers are ideal for battery-powered solutions, e.g., in IoT applications.The DRO dendrometer is specially designed to measure roots, aquatic plants and installations with ground contact, e.g. on ground cover plants. Sealed by a soft, yet resilient rubber coating protects the entire sensor and the sensor rod from the ingress of water and particles; the device is water- and dustproof. An additional metal bracket protects the signal-receiving sensor from pressure that may be exerted when buried under soil insubterranean installations. The specific weight of the entire device is similar to that of water. In underwater installations, the device’s buoyancy compensates for its own weight so that no additional load is exerted on the measurement tool.

Advantages of the DD-RO

  • Waterproof, suitable for subterranean, aboveground, and underwater applications
  • Low pressure at the measuring point
  • No additional load on underwater measuring objects
  • Ideal for long-term measurements

Limits of the DD-RO dendrometer

  • Only suitable for diameters smaller than 2 cm (for root diameters> 2 cm on request)


ModelsSuitable fordiameterMeasurement range
DD-RO0 – 2 cm (> 2 cm auf Anfrage)11 mm

Technical data

Sensor model name

Root/Underwater Dendrometer

Type DD-RO (hermetically sealed)

Scope of application

Slow/average growth rates

Suitable for diameter

0 – 2 cm (> 2 cm on request)

Special features/limitations

Sealed to withstand with a wide range of operational conditions; see below.

Measurement range

11 mm linear


Data logger dependent e.g.:

CR300 series: 0.01 µm

Dendrometer logger DL18: 0.2 µm


Dendrometer dependent: max. ± 4.5% of the measured value (stable offset)

Data logger dependent e.g:

CR300 series: ± (0.04% of the measured value +0.3 µm)

Dendrometer logger DL18: ± (0.1% of the measured value +0.45 µm)

Output signal

Analogue, 0V to Vex (excitation supply voltage)

Temperature drift of the sensor

<0.2 µm/°C in the whole measurement range



Operational conditions

Hermetically Sealed Model DD-RO:

normal outdoor field conditions, -25 to 70 °C, 0 to 100% relative air humidity, even under extreme environmental conditions (underwater, below snow cover, under exposure to corrosive substances e.g. salt water, ash, aggressive agricultural chemicals)

Weight (sensor without cable)

30 g

Power supply

Vex (! stabilized !) 0.5 to 10 VDC,

Power consumption max. 0.28 µWh per measurement


Stainless steel and aluminium

Sensor cable length

5 m, extendable on request to max. 100 m


Technical data sheets

Special information for integrators & developers

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Accessories & Compatible Products


From small and compact to an extensive measuring network, Ecomatik offers complete system solutions for sensor data acquisition in any desired size:


The output signal of all Ecomatik dendrometer models is an analogue DC voltage. Our dendrometers are therefore compatible with almost all common data loggers and microcontrollers with analogue voltage input channels (e.g. also Arduino). If you are unsure about the compatibility of an existing data logger, please do not hesitate to contact us.


You need a quotation, have questions about a product, or need extensive technical advice in the context of your project planning. Starting with an initial determination of your needs, through the detailed planning of the required measurement equipment and data transmission technology, up to professional implementation on site, we are at your disposal at any time with advice and action.

General information on order processing

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Assessment of your needs

With your consideration and input, we determine which of our products best meet your needs. We are also happy to design fully-integrated measuring stations (plant, climate, soil sensors), including an independent power supply and mobile data transmission, depending on your requirements.

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Perfect, then just write us an email! In your order, please state the diameter of your measuring objects in addition to the required cable lengths.

Your contact details and Assessment of your needs

Like so many things, everything started with an idea ...

In the case of the plant scientist and founder of ECOMATIK, Dr. Liu, it was the idea that modern measurement technology should enable crucial plant physiological parameters to be measured directly, precisely and with high temporal resolution on the plant itself. It was obvious to him that there is an information potential of immense value in the detailed understanding of immediate reactions of plants to their environment...