HOBO MX Soil Moisture and Temperature Data Logger

Specifications

Soil Moisture: Volumetric Water Content (VWC)

Measurement Range*: 0.00 to 0.64 m³/m³ in mineral soils
0.00 to 0.70 m³/m³ in soilless media
Accuracy: ±0.031 m³/m³ typical in mineral soils that have solution EC <8 dS/m
±0.051 m³/m³ typical in soilless media
Resolution: 0.001 m³/m³
Dielectric Measurement Frequency: 70 MHz

Temperature Sensor (MX2307)

Range: -40 to 100°C (-40 to 212°F), with tip and cable immersion in fresh water up to 50°C (122°F) for one year
Accuracy: ±0.25°C from -40 to 0°C (±0.45 from -40 to 32°F)
±0.2°C from 0 to 70°C (±0.36 from 32 to 158°F)
±0.25°C from 70 to 100°C (±0.45 from 158 to 212°F)
Resolution: 0.04°C (0.072°F)
Drift: <0.01°C per year (0.018°F per year)
Response Time: 3 minutes in air moving 1 m/s; 20 seconds in stirred water
4 minutes in air moving 1 m/s with RS3-B Solar Radiation Shield

Logger

Operating Range: -25° to 60°C (-13° to 140°F)
Radio Power: 1 mW (0 dBm)
Transmission Range: Approximately 30.5 m (100 ft) line-of-sight
Wireless Data Standard: Bluetooth Low Energy (Bluetooth Smart)
Logging Rate: 1 second to 18 hours
Logging Modes: Fixed interval (normal, statistics) or burst
Memory Modes: Wrap when full or stop when full
Start Modes: Immediate, push button, date & time, or next interval
Stop Modes: When memory full, push button, date & time, or after a set logging period
Time Accuracy: ±1 minute per month 0° to 50°C (32° to 122°F)
Battery Type: 2/3 AA 3.6 Volt lithium, user replaceable
Battery Life: 2 years, typical with logging interval of 1 minute and Bluetooth Always On enabled; 5 years, typical with logging interval of 1 minute and Bluetooth Always On disabled. Faster logging intervals and statistics sampling intervals, burst logging, remaining connected with the app, excessive downloads, and paging may impact battery life.
Memory: 110,000 measurements, maximum (472 kB)
Full Memory Download Time: Approximately 60 seconds; may take longer the further the device is from the logger
Dimensions: Logger housing: 10.8 x 5.08 x 2.24 cm (4.25 x 2.0 x 0.88 in.)
Soil moisture sensor: 7.5 x 5.1 x 2.4 cm (2.95 x 2.02 x 0.95 inches)
Soil moisture sensor needle length: 5.4 cm (2.13 inches)
Soil moisture sensor needle diameter: 0.32 cm (0.13 inches)
Temperature sensor (MX2307) diameter: 0.53 cm (0.21 in.)
Sensor cable length: 2 m (6.56 ft)
Weight: MX2306: 229 g (80 oz) MX2307: 267 g (94 oz)
Materials: Logger: Acetal, silicone gasket, stainless steel screws
Soil Moisture Sensor: ASA plastic body with polyurethane epoxy filling and stainless steel pins
Temperature Sensor (MX2307): Stainless steel waterproof tip
Cable: PVC, UV resistant and rodent repellent (soil moisture sensor cable)
Environmental Rating: Temperature sensor and cable (MX2307): Immersion in water up to 50°C (122°F) for 1 year