Fruit Dendrometer
Dendrometer for fruit growth measurement
- Attaches to the plant in seconds
- Lightweight and will not damage the fruit or trunk
- Installation resistant to wind and rain
- Sizes to accommodate different sizes of fruit and trunks
- Stable and adjustment-free operation
- Real-time measurement of fruit and trunk growth
- Swiss design and manufacture
Applications
Fruit crops
Measure fine-granularity climate to enable optimum irrigation
Greenhouses
Micro-climate measurement within greenhouses
Crop research
Maintain optimum germination conditions
Harvesting prediction
Determine crop readiness for harvesting
Yield improvement
Measure crop stress and ensure regular growth to avoid skin cracking
Technical data
Measurements
The fruit dendrometer measures the following:
- Diameter
- Temperature
The data is transferred via an I2C-bus interface. Multiple dendrometers as well as other sensors may be combined on the same bus and share a single radio transceiver hub to transfer data for monitoring and analysis.
There are two categories of I2C registers within the dendrometer:
- Ram registers: values which change often and are not saved after a reset.
- Flash registers: configuration values which are saved after a reset.
Writing to and reading from registers
Configurations registers are read-only by default. ENABLE_MODE_CONFIG must be set to enable write-mode.
Packet format
Register Mapping
Ram:
| Address | Name | Description | Read/Write |
| 0x00 | DIAMETER_OUTPUT_L | low byte diameter 0.01 mm/LSB | R |
| 0x01 | DIAMETER_OUTPUT_H | high byte diameter 0.01 mm/LSB | R |
| 0x02 | TEMPERATURE_OUTPUT_L | low byte temperature 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 when read | R/W |
| 0x7F | ENABLE_MODE_CONFIG | when set all addresses may be written | W |
Flash:
| Address | Name | Description | Read/write |
| 0x8A | CALIBRATION_OFFSET_L | low byte offset on the diameter 0.01 mm/LSB | R |
| 0x8B | CALIBRATION_OFFSET_H | high byte offset on the diameter 0.01 mm/LSB | R |
| 0x8C | TEMPERATURE_OFFSET_L | low byte offset on the temperature 0.1℃/LSB | R |
| 0x8D | TEMPERATURE_OFFSET_H | high byte offset on the temperature 0.1℃/LSB | R |
| 0x8E | DIAMETER_LIMIT_LOW_L | low byte low saturation of the diameter 0.01 mm/LSB | R/W |
| 0x8F | DIAMETER_LIMIT_LOW_H | high byte low saturation of the diameter 0.01 mm/LSB | R/W |
| 0x90 | DIAMETER_LIMIT_HIGH_L | low byte high saturation of the diameter 0.01 mm/LSB | R/W |
| 0x91 | DIAMETER_LIMIT_HIGH_H | high byte high saturation of the diameter 0.01 mm/LSB | R/W |
The fruit dendrometer comprises:
- Spring-loaded arm-assembly with integral sensors and signal conditioning
- Screened cable
- 4-pole waterproof connector (to connect to our transceiver unit or a bus-extender
Measurement
| Temperature | Diameter | |
| Units of measurement | Degree Celsius | mm |
| Resolution | 0.1°C | 0.01 mm |
| Precision | +- 0.3°C | +-0.05 mm |
| Range of measurement | 0°C to 65°C | 19mm to 90mm |
Supply
- 3.3V
- 7.4mA (operating)
Initial configuration
Dendrometers are all delivered with a default I2C address. To combine multiple dendrometers on the same bus each needs to be re-programmed with a unique I2C address; this configuration may either be made at the time of ordering or programmed on-site prior to deployment.
Making measurements
To make a measurement
- Write 1 in the START_MEAS register
- Wait 50 ms for the measurement to be made
- Read the measurement (diameter, temperature) in the output register