HOBOnet Soil Moisture EC-5 Sensor

Highlighted Features

Sensor Features
±3% accuracy in typical soil conditions, and ±2% accuracy with soil-specific calibration
Measures a 0.3-liter volume of soil for taking readings at a specific depth or in a container
High-frequency (70 MHz) circuit provides good accuracy even in high-salinity and sandy soils

Wireless Features
868 MHz wireless mesh self-healing technology
450 to 600 meter wireless range
Up to 50 wireless sensors per RX3000
Simple button-push to join the HOBOnet wireless network
Onboard memory to ensure no data loss
Powered by rechargeable AA batteries and built-in solar panel

The RXW-SMC-xxx sensor supports the following measurement: Soil Moisture

Sensor

Measurement Range

In soil: 0 to 0.550 m³/m³ (volumetric water content)

Extended Range

-0.401 to 2.574 m³/m³

Accuracy

±0.031 m³/m³ (±3.1%) typical 0 to 50°C (32° to 122°F) for mineral soils up to 8 dS/m and ±0.020 m³/m³ (±2%) with soil specific calibration; see Notes 2 and 3

Resolution

0.0007 m³/m³ (0.07%)

Volume of Influence

0.3 liters (10.14 oz)

Sensor Frequency

70 MHz

Sensor Operating Temperature Range

0° to 50°C (32° to 122°F). Although the sensor probe and cable can safely operate at below-freezing temperatures (to -40°C/F), the soil moisture data collected at these extreme temperatures is outside of the sensor's accurate measurement range.

Wireless Mote

Operating Temperature Range

-25° to 60°C (-13° to 140°F) with rechargeable batteries
-40 to 70°C (-40 to 158°F) with lithium batteries

Radio Power

12.6 mW (+11 dBm) non-adjustable

Transmission Range

Reliable connection to 457.2 m (1,500 ft) line of sight at 1.8 m (6 ft) high
Reliable connection to 609.6 m (2,000 ft) line of sight at 3 m (10 ft) high

Wireless Data Standard

IEEE 802.15.4

Radio Operating Frequencies

RXW-SMC-900: 904–924 MHz
RXW-SMC-868: 866.5 MHz
RXW-SMC-922: 916–924 MHz

Modulation Employed

OQPSK (Offset Quadrature Phase Shift Keying)

Data Rate

Up to 250 kbps, non-adjustable

Duty Cycle

<1%

Maximum Number of Motes

50 motes per one RX Wireless Sensor Network

Battery Type/ Power Source

Two AA 1.2 V rechargeable NiMH batteries powered by built-in solar panel or two AA 1.5 V lithium batteries for operating conditions of -40 to 70°C (-40 to 158°F)

Battery Life

With NiMH batteries: Typical 3–5 years when operated in the temperature range -20° to 40°C (-4°F to 104°F) and positioned toward the sun (see Deployment and Mounting), operation outside this range will reduce the battery service life
With lithium batteries: 1 year, typical use

Memory

16 MB

Dimensions

Cable length: 5 m (16.4 ft)
Mote: 16.2 x 8.59 x 4.14 cm (6.38 x 3.38 x 1.63 inches)

Weight

Mote: 223 g (7.87 oz)

Materials

Sensor: Weatherproof
Mote: PCPBT, silicone rubber seal

Environmental Rating

Mote: IP67, NEMA 6

Compliance Marks

RXW-SMC-900
RXW-SMC-868
RXW-SMC-922