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The ECH2O
Probe is a new, low-cost sensor for measuring volumetric water
content of soil and other porous materials. it is inexpensive
enough to allow you to install several of them in your field or plot
without breaking the bank.
It finds the
rate of change of voltage applied to the sensor once it is buried in
the soil. There are other probes that measure water content this
way, but the ECH2O probe is the only one of its kind to
have a comparatively low sensitivity to saline and temperature
effects in the soil.
ECHO measures
the dielectric constant or permittivity of the material in which it
is embedded
ECHO's
circuitry minimizes effects due to temperature variation, and its
probe coating minimizes salinity effects. Soil texture affects the
ECHO calibration to about the same extent that it does any other
dielectric sensor.
SPECIFICATIONS
- Range:
0
to saturation, volumetric water content
- Measurement
time:
10ms
- Accuracy:
±3% typical
± 1% with soil-specific calibration
- Resolution:
0.002m3/m3
- Output Range:
Dry soil: 375 to 1000mV
Air: 255 to 260mV
- Power:
Requirements: 2VDC @ 3mA to 5VDC @ 7mA
Output: 10-40% of excitation voltage (250-1000mV at 2500mV
excitation
- Operating
Temperature:
0-50°C
- Dimensions:
10"(25.4cm)total length x 1.25"(3.17cm)wide x 1.5mm
thick. Sensing area is 20cm in length.
- Connector
Type:
3.5mm plug, 3-wire adapter cable included
- Datalogger
compatibility
(including, but not limited to):
Decagon Em5 and Em5R, Campbell Scientific CR10, CR10X, 21X, 23X,
CR510
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