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Smart Water Sensor Probes

Group of sensors designed for Smart Water applications

Libelium Waspmote Smart Water model has been conceived to facilitate the remote monitoring of the most relevant parameters related to water quality. With this platform you can measure more than 6 parameters, including the most relevant for water control such as dissolved oxygen, oxidation-reduction potential, pH, conductivity and temperature. An extremely accurate turbidity sensor has been integrated as well.

The Smart Water Ions line is complementary for these kinds of projects, enabling the control of concentration of ions like Calcium (Ca2+), Fluoride (F-), Fluoroborate (BF4-), Nitrate (NO3-), Bromide (Br-), Chloride (Cl-), Cupric (Cu2+), Iodide (I-), Lead (Pb2+), Silver (Ag+) and pH.

Soil/Water Temperature sensor probe

Sensor specifications
  • Measurement range: 0 ~ 100ºC
  • Accuracy: DIN EN 60751
  • Resistance (0ºC): 1000Ω
  • Diameter: 6mm
  • Length: 40mm Cable: 2m

The resistance of the Pt1000 sensor varies between approximately 920Ω and 1200Ω in the range considered useful in agriculture applications (-20 ~ 50ºC approximately), which results in too low variations of voltage at significant changes of temperature for the resolution of the Waspmote’s analog-to-digital converter. The temperature value is returned in Celsius degree (ºC).

Conductivity sensor probe

Sensor specifications
  • Sensor type: Two electrodes sensor
  • Electrode material: Platinum
  • Conductivity cell constant: 1 ± 0.2 cm-1

The conductivity sensor is a two-pole cell whose resistance varies in function of the conductivity of the liquid it is immersed in. That conductivity will be proportional to the conductance of the sensor (the inverse of its resistance), multiplied by the constant cell, in the case of the Libelium sensor around 1cm-1, leading to a value in Siemens per centimeter (S/cm).

Dissolved Oxygen sensor probe

Sensor specifications (PIR)
  • Sensor type: Galvanic cell
  • Range: 0~20mg/L
  • Accuracy: ±2%
  • Maximum operation temperature: 50ºC
  • Saturation output: 33mV ±9mV
  • Pressure: 0~100psig (7.5Bar)
  • Calibration: Single point in air
  • Response Time: After equilibration, 2 minutes for 2mV

The galvanic cell provides an output voltage proportional to the concentration of dissolved oxygen in the solution under measurement without the need of a supply voltage. This value is amplified to obtain a better resolution and measured with the analog-to-digital converter placed on the Smart Water board.

This sensor should be calibrated with the calibration solution for more accurate measurements.

pH sensor probe

Sensor specifications
  • Sensor type: Combination electrode
  • Measurement range: 0~14pH
  • Temperature of operation: 0~80ºC
  • Zero electric potential: 7±0.25p
  • Response time: <1min
  • Internal resistance: ≤250MΩ
  • Repeatability: 0.017 PTS: >98.5
  • Noise: <0.5mV Alkali error: 15mV
  • Reader accuracy: up to 0.01 (in function of calibration)

The pH sensor integrated in the Smart Water board is a combination electrode that provides a voltage proportional to the pH of the solution, corresponding the pH 7 with the voltage reference of 2.048V of the circuit, with an uncertainty of ±0.25pH. To get an accurate value from these sensors it is necessary both to carry out a calibration and to compensate the output of the sensor for the temperature variation from that of the calibration moment.

Oxidation-reduction potential sensor probe

Sensor specifications
  • Sensor type: Combination electrode
  • Electric Potential: 245~270mV
  • Reference impedance: 10kΩ
  • Stability: ±8mV/24h

Like the pH sensor, the ORP probe is a combination electrode whose output voltage is equivalent to the potential of the solution, so it will share the connection sockets with that sensor. The output of the circuitry to which it is connected is directly read from the analog-to-digital converter of the Smart Water sensor board, being the 2.048V reference subtracted to obtain the actual oxidation-reduction potential in volts (in this case, since this parameter is directly a voltage it is not necessary to call a conversion function).

Turbidity sensor probe

Sensor specifications
  • Sensor type: IR optical sensor with optical fibre
  • Measurement range: 0-4000 NTU
  • Accuracy: 5% (around 1 NTU in the lower scale)
  • Robust and waterproof : IP68
  • Digital output: Modbus RS-485
  • Power consumption : 820 μA
  • Power supply: 5 V
  • Stocking temperature: -10 to +60 °C
  • Material: PVC, Quartz, PMMA, Nickel-plated brass

The turbidity sensor is extremely sensitive and the user must treat it with especial care in all situations (laboratory tests, development, installation, etc). The sensor must be installed in a solid way and protected from any impact.

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Libelium, Plug & Sense Soil/Water temperature (Pt-1000) Sensor

DNA Part Code: LI-9255-P
Libelium MPN: 9255-P

Libelium, Plug & Sense Conductivity Sensor

DNA Part Code: LI-9326-P
Libelium MPN: 9326-P

Libelium, Plug & Sense Dissolved Oxygen Sensor

DNA Part Code: LI-9327
Libelium MPN: 9327

Libelium, Plug & Sense pH Sensor

DNA Part Code: LI-9328
Libelium MPN: 9328

Libelium, Plug & Sense Oxidation Reduction Potential Sensor

DNA Part Code: LI-9329
Libelium MPN: 9329

Libelium, Plug & Sense Turbidity Sensor

DNA Part Code: LI-9353-P
Libelium MPN: 9353-P