Sensors are measurement devices that are connected to wireless nodes. The environmental values that can be measured by the ClimateMinder sensor nodes are:
- Ambient temperature and humidity
- Soil moisture
- Soil moisture, temperature and electrical conductivity (EC)
- Solar radiation
- Leaf wetness
These sensors are commercially available OEM units that have been modified to work with ClimateMinder wireless nodes:
Ambient Temperature and Humidity Sensor
The SHT75 digital humidity and temperature sensor is the high-quality version of Sensirion humidity sensor series with cutting edge accuracy. A unique capacitive sensor element is used for measuring relative humidity while temperature is measured by a band-gap sensor. The capacitive humidity sensor SHT75 is fully calibrated and provides a digital output. Every humidity sensor is tested upon quality and accuracy compliance. Certficate of conformance on batch level is available on request.
- Relative humidity operating range: 0 – 100% RH
- Accuracy (humidity): +/- 1.8% RH
- Typical resolution (humidity): 0.05 % RH
- Temperature operating range: -40 – +125°C (-40 – +257°F)
- Accuracy (temperature): +/- 0.3 °C
- Typical resolution (temperature): 0.01 °C
The Decagon ECH2O Dielectric Aquameter sensors for measuring soil water content will enable you to monitor soil moisture accurately and affordably
The ECH2O probe measures the dielectric constant of the soil in order to find its volumetric water content. Since the dielectric constant of water is much higher than that of air or soil minerals, the dielectric constant of the soil is a sensitive measure of water content.
The two-prong design and higher measurement frequency allows the EC-5 to measure VWC from 0 to 100%, and allows accurate measurement of all soil types and a much wider range of salinities.
- Accuracy: at least 0.003 m3/m3 all soils, up to 8 dS/m with soil-specific calibration: ±.02 m3/m3 (±2%)
- Resolution: 0.001 m3/m3 VWC in mineral soils, 0.25% in growing media
- Operating Environment: -40 to +60 °C
- Range of Measurement: 0 to 100% VWC (variable water content)
- Probe dimensions: 8.9cm x 1.8cm x 0.7cm
The Decagon 5TE is designed to measure the water content, electrical conductivity, and temperature of soil and growing media. Using an oscillator running at 70 MHz, it measures the dielectric permittivity of soil to determine the water content. A thermistor in thermal contact with the probe prongs provides the soil temperature, while the screws on the surface of the sensor form a two-probe electrical array to measure electrical conductivity.
- Dimensions: 10 cm (1) x 3.2 cm (w) x 0.7 cm (d)
- Prong Length: 5.2 cm
- Operating Temperature: -40-50 °C Volumetric water content:
- Range: Apparent dielectric permittivity (εa): 1 (air) to 80 (water)
- Resolution: εa: 0.1 εa (unitless) from 1-20, ‹0.75 εa (unitless) from 20-80
- VWC: 0.0008 m3/m3 (0.08% VWC) from 0 to 50% VWC
- Accuracy: (εa): ±1 εa (unitless) from 1-40 (soil range), ±15% from 40-80
- (VWC):
- Using Topp equation: ±0.03 m3/m3 (±3% VWC) typical in mineral soils that have solution electrical conductivity ‹10 dS/m
- Using medium specific calibration, ±0.01 - 0.02 m3/m3 (± 1-2% VWC) in any porous medium
Electrical Conductivity (bulk)
- Range: 0-23 dS/m (bulk)
- Resolution: 0.01 dS/m from 0 to 7 dS/m, 0.05 dS/m from 7 to 23 dS/m
- Accuracy: ±10% from 0 to 7 dS/m, user calibration required above 7 dS/m Temperature
- Range: -40-50 °C
- Resolution: 0.1 °C
- Accuracy: ±1 °C
The SP-110 Pyranometer Sensor, or solar radiation sensor, is calibrated to measure the shortwave radiation reaching the Earth's surface, measured in Joules m-2 s-1 or Watts m-2. The evaporation of water from soil and the transpiration of water from plant leaves are partly determined by the intensity of shortwave radiation
- Designed for continuous outdoor use (-40 to 55º C)/li>
- Responsivity: 0.20 mV per W m-2
- In Full Sunlight: 1100 W m-2
- Linear Range: 0 - 1750 W m-2
- Accuracy: ± 5%
The Decagon Leaf Wetness Sensor (LWS) determines the presence and duration of canopy wetness, allowing you to forecast disease and protect the plant canopy. Because the Leaf Wetness Sensor measures the dielectric constant, droplets do not need to bridge electrical traces for the sensor to detect moisture. The presence of water or ice anywhere on the surface of the sensor will be detected. The sensor measures leaf surface wetness by measuring the dielectric constant of the sensor’s upper surface.
- Output: 320-1000 mV @ 3V excitation
- Operating Environment: -20 to 60°C
- Probe Dimensions: 11.2cm x 5.8cm x .075 cm
These sensor descriptions and specs are taken from respective manufacturers Web sites, and ClimateMinder accepts no responsibility for the accuracy of this information. Manufacturers reserve the right to change the sensor specs without notice.
ClimateMinder, GrowFlex, and GrowMobile are trademarks of ClimateMinder, Inc. All other trademarks are the property of their respective owners.