FieldKit Underwater

The technology that dominates the field of underwater sensing tends to cost multiple thousands of dollars, creating a large barrier to entry for many who need data on underwater conditions over long periods of time at high frequencies. The low-cost FieldKit Underwater is an open source alternative.

The FieldKit Underwater platform is intended to be a multi-parameter datalogging sonde for fully submerged use for long deployments on the order of months. The design of the unit enables the use of multiple rechargeable lithium ion battery packs and high-capacity µSD cards for extended deployment periods. The unit is designed to gather data from multiple sensors, and includes circuits to interface with probes for dissolved oxygen, pH, electrical conductivity, external temperature, and oxidation reduction potential on-board. Also included is a pressure and temperature sensor. In the initial prototype embodiments, probes and sensors for pH, EC, DO, pressure, and temperature are included on the bulkhead plate along with the vent port for pressure testing the enclosure.

FieldKit Underwater - pH specifications

pH 0.001 to 14.000 (±0.002)
Probe diameter 12 mm
Temperature range 0-99 °C
Cable length 1 m
Interface SMA connector on 50 Ω coaxial cable
Calibration period 6 months
Panel footprint 1 SMA connector
Bulkhead plate footprint 1 ¾” NPT probe gland
Current consumption 16 mA

FieldKit Underwater - Electroconductivity specifications

Conductivity 0 to 500000 (±10000) µS/cm
Probe diameter 12 mm
Temperature range 1-60 °C
Cable length 2 m
Interface SMA connector on 50 Ω coaxial cable
Calibration period 6 months
Panel footprint 1 SMA connector
Bulkhead plate footprint 1 ¾” NPT probe gland
Current consumption 30 mA

FieldKit Underwater - Dissolved Oxygen specifications

Dissolved Oxygen 0.01 to 100 (±0.05) %O2
Probe diameter 16.4 mm
Temperature range 1-60 °C
Cable length 2 m
Interface SMA connector on 50 Ω coaxial cable
Calibration period 6 months
Panel footprint 1 SMA connector
Bulkhead plate footprint 1 ¾” NPT probe gland
Current consumption 16 mA

FieldKit Underwater - Pressure and Temperature specifications

Pressure 0.01-2.00 (±0.05) bar
Temperature 2.0-40.0 (±0.1) °C
Probe diameter 16 mm
Temperature range -20-85 °C
Cable length 45 cm
Interface 4-pos JST GH connector on 4 24 AWG conductors (I2C @ 3.3 V)
Calibration period 1 year
Panel footprint 1 4-pos JST GH connector
Bulkhead plate footprint 1 M10 through hole
Current consumption 1.5 mA