HOBOnet 45cm soil moisture and temperature sensor

The HOBOnet Multi-Depth Soil Moisture Sensor is a wireless sensor that works with the HOBOnet system to measure soil moisture and soil temperature at multiple depths with a single probe, for fast and easy installation. This durable sensor is available in three probe lengths for measurements from 45 cm deep.

Featuring GroPoints TDT5 technology with patented antenna design, these sensors measure soil moisture along the entire length of each probe segment, resulting in the largest volume of influence per measurement section. A high frequency of pulses per measurement provides precise and consistent soil moisture data.

The HOBOnet system is a cost-effective and scalable wireless sensor network for web-enabled monitoring of field conditions for applications such as crop management, research, and greenhouse operations. And because its wireless, you can deploy a network of sensors to easily monitor multiple points with a single system, while avoiding the risk of long cables that can interfere with field operations. Sensors are easily linked to the network, and data can be accessed through HOBOlink, Onset's innovative cloud-based software platform.

Sensor Features:

- 45 cm probe length
- Soil moisture measurements over entire probe segment lengths
- Soil temperature measurements at multiple points
- Largest volume of influence per measurement (2 L volume of influence per 15 cm segment)
- Advanced filtering of 400,000 pulses per measurement eliminates outlying readings and provides precise, repeatable soil moisture data
- Polycarbonate housing and epoxy-sealed circuit board protect vital components during installation and throughout deployment
- Easy installation with minimal soil disturbance, and no digging required when using the optional pilot rod and slide hammer

Wireless Features:

- 916 to 924 MHz MHz wireless mesh self-healing technology
- 450 to 600 meter (1,500 to 2,000 feet) wireless range and up to five hops
- Up to 50 wireless sensors per HOBO RX station
- 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

Includes:

- HOBOnet Multi-Depth Soil Moisture Sensor
- Two AA 1.2V rechargeable NiMH batteries
- Cable ties
- Screws

Specifications

Soil Moisture: Volumetric Water Content (VWC):

- Measurement Range: 0.000 to 1.000 m/m in most soils
- Accuracy: +/- 0.02 m/m (+/- 2%) in most soils typical from 0 to 50 C (32 to 122 F)
- Resolution: 0.001 m/m

Temperature:

- Measurement Range: -20 to 70 C (-4 to 158 F)
- Accuracy: +/- 0.5 C (0.9 F)
- Resolution: 0.1 C (0.18 F)

Depths Measured (see below):

- 45 cm total; three soil moisture zones, six temperature depths

Wireless Mote:

- Operating Temperature Range (Sensor): -20 to 70 C (-4 to 158 )
- Operating Temperature Range (Mote): -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
- Modulation Employed: OQPSK (Offset Quadrature Phase Shift Keying)
- Data Rate: Up to 250 kbps, non-adjustable
- Duty Cycle: <1%
- Maximum Number of Motes: Up to 50 wireless sensors or 336 data channels per one HOBO RX station
- Radio Operating Frequency: 916 to 924 MHz

Logging Rate (With batteries):

- 5 minutes year round

Logging Rate (Using Non-Rechargeable Lithium Batteries):

- 10 minutes

Number of data channels:

- 10

Battery Life

With NiMH batteries: Typical 35 years when operated in the temperature range -20 to 40 C (-4 F to 104 F) and positioned toward the sun (see Mounting and Positioning the Mote), operation outside this range will reduce the battery service life

With non-rechargeable lithium batteries:

- 1 year with a 10-minute logging interval

Dimensions:

- Sensor length: 53.2 cm (20.9 inches)
- Sensor diameter: 3 cm (1.2 inches)
- Cable length: 3 m (9.8 ft)
- Mote: 16.2 x 8.59 x 4.14 cm (6.38 x 3.38 x 1.63 inches)