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US 9,804,113 B2Granted
Soil moisture sensor
AssigneeFiskars Oyj Abp
InventorsHari Hara Kumaran, Vibha Tomar
Life of this patent
Estimating the term…
Abstract
A soil moisture sensor includes a capacitive probe configured to be inserted into soil, a series RLC circuit electrically coupled to the capacitive probe, a microcontroller configured to determine the capacitance value of the soil and determine the moisture content of the soil from the capacitance value of the soil.
Claims19
A soil moisture sensor, comprising:
- a capacitive probe configured to be inserted into soil;
- a series RLC circuit electrically coupled to the capacitive probe;
- and
- a microcontroller configured to
- provide a drive signal having a predetermined drive signal frequency to the series RLC circuit,
- receive an output signal including one of an output voltage or an output current from the capacitive probe,
- determine the capacitance value of the soil based at least in part on the received output signal, and
- determine the moisture content of the soil based on the determined capacitance value.
5 more elements
A soil moisture sensor, comprising:
- a capacitive probe comprising two electrodes configured to be inserted into soil and to provide an output signal dependent on the capacitance of the soil between the two electrodes;
- a series RLC circuit electrically coupled to, and providing an input signal to the capacitive probe to induce the output signal;
- a current-to-voltage converter configured to receive the output signal, and convert the output signal to a proportional output voltage;
- and
- a microcontroller comprising
- a pulse-width modulated signal generator configured to provide a drive signal having a predetermined drive signal frequency to the series RLC circuit, the predetermined drive signal frequency is selected with reference to a resonance curve of the series RLC circuit, and
- an analog-to-digital converter configured to receive the proportional output voltage, and convert the proportional output voltage to a digital signal,
- the microcontroller configured to determine a capacitance value of the soil based on the digital signal, and to determine the moisture content of the soil in view of the capacitance value of the soil and a dielectric constant of the soil.
5 more elements
Dependencies are inferred from the claim text.