The invention presents a design for sensor electrodes and a circuit aimed at measuring soil moisture and bulk electrical conductivity. Soil moisture is assessed by detecting changes in the frequency of an LC oscillator, which vary with soil moisture levels altering the equivalent capacitance of the tank circuit. The oscillator operates within a frequency range of 100 MHz to 250 MHz, necessitating a frequency divider to scale down the signal for measurement by a microcontroller. The microcontroller also generates low-frequency excitation pulses applied to the probes to measure electrical conductivity. The sensor comprises three stainless steel probes arranged in parallel. Soil moisture is measured between the first and second probes, where the first probe serves as the excitation probe and the second as the ground. Electrical conductivity, on the other hand, is gauged between the second and third probes, with the second probe acting as the ground and the third as the excitation probe.
- Simple circuit which can operate at high frequencies used for moisture measurement
- Robust probes which can be directly used in hard and dense soils
- Calculations done by the microcontroller unit present in the device
- Includes an LCD module for reading the measurements
- Includes microSD card module for storing the data if needed
- Low-cost compared to the devices available in the market that measure both soil moisture and electrical conductivity
The invention comprises a device designed for simultaneous measurement of soil moisture and electrical conductivity. It incorporates several key components: probes made of three parallel stainless-steel rods, a soil moisture sensing circuit, a soil conductivity sensing circuit, a microcontroller module, an LCD display module, a microSD card module, and a power supply circuit. The probes are integral to both sensing circuits: the first and second rods are used for soil moisture measurement, where the first rod connects to a high-frequency LC oscillator to detect changes in moisture content. The second rod serves as a common ground connection. For electrical conductivity measurement, conducted between the second and third rods, the third rod is connected to the microcontroller via a reference resistor in series.
The invention is at the stage of prototype demonstration and/or pilot scale system validation in relevant environment. Prototype testing was done on different soil types and moisture and bulk electrical conductivity was accurately measured.
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The invention has the potential to enhance agricultural resource use efficiency, promote agricultural and environmental sustainability, and stimulate technological advancement in agriculture-dependent regions while simultaneously being cost-effective for farmers.
Agricultural industry
The main application of this invention is in the agricultural industry. It can be used by farmers to measure the moisture in their soil and to analyse the properties of the soil for further research which could help to develop improved farming techniques.
202221018842
535460