Fruit dendrometer

Dendrometer for measuring fruit growth

  • Attaches to the plant in seconds
  • Lightweight and does not damage the fruit or trunk
  • Wind- and rain-resistant installation
  • Dimensions to suit different fruit and trunk sizes
  • Stable, adjustment-free operation
  • Real-time measurement of fruit and trunk growth
  • Swiss design and manufacture

Applications

Orchards

Measuring the climate to optimise irrigation

Greenhouses

Measuring the microclimate in greenhouses

Crop research

Maintaining optimum germination conditions

Harvest forecast

Determining whether crops are ready for harvesting

Improving performance

Measuring crop stress and ensuring regular growth to prevent skin damage

Technical data

Measures

The fruit dendrometer measures the following elements:

  • Diameter
  • Temperature

Data is transferred via a bus interface I2C. Several dendrometers and other sensors can be combined on the same bus and share a single radio transceiver to transfer data for monitoring and analysis. The dendrometer has two categories of registers

  1. Ram registers: values that change frequently and are not saved after a reset.
  2. Flash registers: configuration values saved after a reset.

Writing and reading in registers

Configuration registers are read-only by default. ENABLE_MODE_CONFIG must be set to enable write mode.

Package format

Register mapping

Ram :

Address Name Description Reading/Writing
0x00 EXIT_DIAMETER_L low byte diameter 0.01 mm/LSB R
0x01 EXIT_DIAMETER_H high byte diameter 0.01 mm/LSB R
0x02 TEMPERATURE_OUTPUT_L low byte diameter 0.1℃/LSB R
0x03 TEMPERATURE_OUTPUT_H high byte temperature 0.1℃/LSB R
0x06 START_MEAS write 1 to start measurement. always 0 if reading R/W
0x7F ENABLE_MODE_CONFIG when enabled, all addresses can be written to W

Flash:

Address Name Description Reading/Writing
0x8A CALIBRATION_OFFSET_L 0.01 mm/LSB diameter low byte offset R
0x8B CALIBRATION_OFFSET_H high byte offset on diameter 0.01 mm/LSB R
0x8C TEMPERATURE_OFFSET_L temperature low byte offset 0.1℃/LSB R
0x8D TEMPERATURE_OFFSET_H temperature high byte offset 0.1℃/LSB R
0x8E DIAMETER_LIMIT_LOW_L low byte low saturation of diameter 0.01 mm/LSB R/W
0x8F DIAMETER_LIMIT_LOW_H High saturation of the low byte of the diameter 0.01 mm/LSB R/W
0x90 DIAMETER_LIMIT_HIGH_L low byte high saturation of diameter 0.01 mm/LSB R/W
0x91 DIAMETER_LIMIT_HIGH_H high byte high diameter saturation 0.01 mm/LSB R/W

The fruit dendrometer includes

  • Spring arm with integrated sensors and signal conditioning
  • Shielded cable
  • 4-pole waterproof connector (for connection to our transceiver unit or to a bus extender)

Measures

 Temperature Diameter
Measurement units Degrees Celsius mm
Resolution 0.1°C 0.01 mm
Precision +- 0.3°C +-0.05 mm
Measurement range 0°C to 65°C 19mm to 90mm

Sourcing

  • 3.3V
  • 7.4 mA (operating)

Initial configuration

All dendrometers are supplied with a default I2C address. To combine several dendrometers on the same bus, each must be reprogrammed with a unique I2C address; this configuration can be carried out when the order is placed or programmed on site before deployment.

Taking measurements

To make a measurement

  1. Write 1 to the START_MEAS register
  2. Wait 50 ms for the measurement to be taken
  3. Read the measurement (diameter, temperature) from the output register