What is difference between soil moisture sensor and relative humidity sensor?

Soil Moisture Sensors and Relative Humidity Sensors are two different types of sensors that each play an important role in environmental monitoring, but measure different physical quantities and have different application scenarios.

Soil Moisture Sensor

Definition:

A soil moisture sensor, also known as a soil moisture sensor, soil moisture sensor, or soil water content sensor, is a device designed to measure the relative water content of soil. It is usually buried in the soil and infers the soil's water content by detecting the soil's dielectric constant or resistivity. It is widely used in agriculture, forestry, environmental protection and scientific research, etc. Especially in precision agriculture, it helps farmers to adjust the irrigation schedule according to the actual moisture content of the soil, thus saving water resources and improving crop yield.

Soil moisture sensor working principle:

Soil moisture sensors work on a variety of principles, mainly including the following:

FDR (Frequency Domain Reflection) principle: Using the electromagnetic pulse principle, the apparent dielectric constant of the soil is measured according to the frequency of electromagnetic wave propagation in the medium, so as to get the relative water content of the soil. This method has the advantages of simplicity and safety, rapidity and accuracy, continuous fixed point, automation, wide range and less calibration.

Resistance method: Determine the soil moisture content by measuring the resistance of the moisture in the soil. The higher the moisture content, the lower the resistance.

Capacitance method: Measure soil moisture by utilizing the property that the capacitance value of soil changes with humidity.

Soil moisture sensor applications:

  - Mainly used in agricultural irrigation, plant growth monitoring, soil science research, hydrogeology and other fields.

  - Used to optimize irrigation schedules, monitor crop water requirements, and study soil moisture dynamics.

Relative Humidity Sensor

Definition:

A relative humidity sensor is a sensor used to measure the relative humidity in the air. It is used to measure the ratio of the amount of water vapor in the air to the amount of saturated water vapor at the same temperature, usually expressed as a percentage. It is widely used in indoor air conditioning, industry, medicine, agriculture, cultural relics protection and other fields to help users understand the degree of humidity in the air so as to regulate and control accordingly.

Relative humidity sensor working principle:

The working principle of the relative humidity sensor mainly utilizes the change of resistance value to measure humidity. Under the condition of a certain temperature, the higher the absolute temperature and air pressure of the air, the drier the air and the higher the resistance; on the contrary, it means that the air is humid. By detecting the voltage signal in the circuit, it is possible to determine the degree of humidity of the air in the measured environment.

Relative humidity sensor applications:

  - Mainly used in indoor environmental control, meteorological monitoring, industrial manufacturing, warehousing and logistics, medical equipment, laboratory research, food and beverage industry.

  - It is used to regulate indoor comfort, monitor climate change, control the production environment and ensure product quality.

- In weather forecasting, relative humidity is one of the most important indicators for determining weather changes.

Difference between Soil Moisture Sensor and Relative Humidity Sensor

 In summary, soil moisture sensor and relative humidity sensor in the definition, working principle, application and measurement object and so on there are obvious differences. In practical application, it is necessary to choose the appropriate sensor according to the specific needs.

 Summarize

Although soil moisture sensors and relative humidity sensors are both used for humidity measurement, there are significant differences in the media they target, the principle of operation, application scenarios and measurement units. Soil moisture sensors focus on soil moisture management, while relative humidity sensors are more widely used in air humidity monitoring and control. The two differ in measurement principle, installation method, application areas, etc. Understanding these differences will help you choose the right type of sensor for your specific application to meet your specific monitoring needs.

Soil Moisture Temperature sensor data sheet

NBL-S-THR-Soil-temperature-and-moisture-sensors-Instruction-Manual-V4.0.pdf

NBL-S-TMC-Soil-temperature-and-moisture-conductivity-sensor.pdf

Atmospheric Temperature Humidity and pressure Sensor data sheet

NBL-W-LBTH-Atmosphere-temperature-humidity-and-pressure-sensor-instruction-manual-V4.0.pdf

NBL-W-WHT-Wall-Mounted-Temperature-Humidity-Sensors-Instruction-Manual.pdf