Moisture Sensor PCB

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How does a moisture sensor circuit work?

The soil moisture sensor consists of two probes that measured the volume of the water in the soil.

The two probes allows the electric current to go through the soil, according to the resistance, measure the moisture level of the soil. So the moisture level will be very higher. Dry soil decrease conductivity.

moisture sensor circuit work
Is moisture sensor analog or digital?

Is moisture sensor analog or digital?

This sensor measures the volumetric substance of water inside the soil and it takes us the moisture level as output.

The sensor is furnished with both analog and digital output, so it could be used in both analog and digital mode.

What is the purpose of soil moisture sensor?

Soil moisture sensors measure or estimated the amount of water in the soil.

These sensors could be stationary or portables like as handheld probes.

Stationary sensors is placed at the predetermin place and depth in the field, thus,portable soil moisture probes could be measured soil moisture at several places.

purpose of soil moisture sensor

Venture Moisture Sensor PCB

moisture sensor pcb

Venture is a leading manufacturer and supplier of Moisture Sensor PCB. We have more than 10 years of experience in this area.

We aim to provide high-quality, durable, and the best Moisture Sensor PCB for our beloved customers.

In order to achieve our goal, we are striving to do our best and give you a satisfying moisture sensor PCB with excellent services.

Your Leading Moisture Sensor PCB Design Supplier in China

moisture sensor pcb

If you are looking for the best Moisture Sensor PCB, then you are in the right place!

Venture  offers two Moisture Sensors PCB for your selection, both affordable and easy to use with outstanding performance.

We assure you of our quality products. All of our products are guaranteed and proven.

Venture is offering cost-effective Moisture Sensor PCB products.

moisture sensor pcb

We have a wide selection of Moisture Sensor PCB so that you can select your desired Moisture Sensor PCB.

You can send your own design of Moisture Sensor PCB. We are happy to provide your needs.

Venture has the best PCB solutions in the market. We are specialized in providing high customer service.

moisture sensor pcb

Venture has a great experience in supplying moisture sensor PCB to different industries throughout the world.

So, if you need excellent quality and certified manufacturer of  moisture sensor PCB, Venture is the best option for you.

We accept small or large orders of moisture sensor PCBs.

Contact us for more details.

Moisture Sensor PCB: The Ultimate FAQ Guide


If you’re looking for any information about moisture sensor PCB, you will find it right here.

So, if you want to be an expert in moisture sensor PCB read this guide.

What Is Moisture Sensor PCB?

Moisture Sensor PCB refers to a printed circuit board used in moisture sensor modules that helps in detecting moisture level, especially in soil.

It determines the volumetric water content in the soil and relay the level of moisture as output.

Most water sensor PCBs feature both digital and analog output, therefore, you can use them in both digital and analog mode.

Moisture Sensor PCB

Moisture Sensor PCB

What Are The Applications of Moisture Sensor PCB?

The common uses of moisture sensor PCB include:


Determining the moisture content of soil is essential in agricultural applications. This is because the measurement enables farmers to control their irrigation mechanism more efficiently.

Knowing the precise moisture conditions of the soil guides farmers to generally utilize less water for growing crops. Moreover, they are capable of increasing the quality and yield of crop due to advanced soil moisture management during crucial plant growth phase.


Soil moisture sensor PCBs find application in various research applications, for instance in agricultural science including planning for irrigation. Also, they are used in environmental science or climate research comprising of solute transport research and as secondary sensors in soil respiration assessments.

Landscape Irrigation

Within suburban and urban areas, residential lawns and landscapes are utilizing moisture sensor PCB devices to link with irrigation controller.

Linking a moisture sensor module to a basic irrigation clock transforms it to “smart irrigation controller.

This helps in preventing irrigation cycles if soil is already moist, for example after rainfall.

Additionally, golf courses also utilize moisture sensor PCB gadgets to boost their irrigation systems efficiency.

Using the moisture sensor modules help in preventing excessive watering and fertilizer and other chemicals leaching into the ground.

Moisture Sensors For Gardener

There are comparatively affordable and simple moisture sensor PCB devices, which do not need a source of power.

You can use them for confirming whether plants have adequate moisture to grow.

By lodging a probe in the soil for about 60 seconds, a gauge displays if the soil is excessively moist or dry for the plants.

Which Are The Type Of Dielectric Sensors Used In Soil Moisture Sensor PCB?

Dielectric sensors refer to general type of sensors that determine the soil charge-storing capacity. The charge-storage technique is more efficient in comparison to resistance technique.

There exist different dielectric sensor types available. The most popular dielectric sensors applied in moisture sensor PCB include the following:

Capacitance Sensor

The soil acts as the capacitor element in a capacitance sensor. It employs the charge storing capability of the soil to calibrate to content of water.

The sensor operates by measuring the capacitance change due to the dielectric changes.

It doesn’t measure moisture directly since pure water is a poor conductor of electricity.

Rather, it measures the dissolved ions in the moisture.

Capacitive moisture sensor basically determines the dielectric created by the soil, with water being the most crucial parameter that influences the dielectric.

One of the advantages of capacitance moisture sensor is the fact that it avoids direct display of the probes.

This in turn helps in preventing corrosion of probes and the moisture sensor itself.

Capacitance moisture sensor also provides a better measurement of the soil moisture content compared to resistive moisture sensor.

The sensor’s capacitance is determined using a 555 timer that generates a voltage equal to the capacitor lodged in the soil.

You then measure the voltage using an analog to digital converter that generates a number which denotes the soil moisture.

Nonetheless, it is essential to note that capacitance detector can only qualitatively assess soil humidity and is not able to measure quantitatively.

This implies that if the soil humidity rises, the output value falls. On the other hand, if the humidity falls, the output value increases.

TDR Sensor

Time-Domain Reflectometry Sensor assesses travel duration of a reflected electrical energy wave down a transmission line.

There is relation between the travel duration, charge storing capability and volumetric water content.

TDR sensors employ parallel rods that serve as transmission lines.  You apply voltage to the rods, which is reflected bounced back to the moisture sensor for evaluation.

There is relation in the voltage speed and the substrate apparent permittivity.

The pulse speed is slower in comparatively wet soil in comparison to drier soil.

TDR constitutes a variety of frequencies within the signal that may assist in reducing errors due to soil salinity.

TDR Moisture Sensor PCB System

TDR Moisture Sensor PCB System

Frequency-Domain Reflectometry (FDR) Sensors

These type of dielectric moisture sensors equally utilizes soil as capacitor to determine the maximal resonance frequency within the moisture sensor PCB.

It senses moisture by relating resonance frequency to soil water content.

FDR sensors applies an oscillator to convey an electromagnetic signal across a metal tine or any other wave guide.

To establish the soil moisture, you measure the variation between return wave frequency and output wave.

FDR moisture sensors are assumed accurate however you must calibrate them for the soil type you will be inserting them in.

They give a quick response time in comparison to TDR moisture sensors.

This type of dielectric sensor used in moisture sensor PCB should have correct contact with the soil you are measuring. You should always ensure that there exist no air gaps.

The measurement volume relies on the size of sensor with majority of FDR sensors ranging from 5cm to 10cm.

Moreover, there exist greater field of influence at the substrate-sensor interface and reduces steadily from there.

Typically, field of influence is about 1cn from the FDR moisture sensor.

What Are The Features Of Capacitive Moisture Sensor PCB?

Capacitive moisture sensor PCB determines soil moisture amount by establishing capacitance changes to determine the water content of a medium.

It employs capacitance instead of resistance to measure the moisture content.

The primary features of capacitive moisture sensor PCB consist of:

  • Analog output of water content
  • More corrosion resistant compared to resistive moisture sensor PCB
  • Has operating voltage of 3.3V or 5V.

Why Are Resistance Sensors Not the Best for Moisture Sensor PCB?

The working principle of resistive moisture sensors is similar to that of capacitive sensors.

They measure an electrical change to generate a value for moisture content.

Nonetheless, the mechanism in resistive moisture sensor is different.

Similar to capacitive moisture sensor PCB, the resistive sensor type also applies a hygroscopic material.

The dissimilarity is that resistive moisture sensor measures the resistance change within the substrate rather than capacitance.

For that matter, there is an inverse exponential relation between the output voltage and moisture content. In capacitive moisture sensors, you can capture, store or convert the output voltage data.

The two moisture sensors utilize inexpensive, scalable dielectrophoresis. A free-standing construction is developed to carry pre-patterned electrodes separated using one crystalline zinc oxide nanowire.

Nevertheless, Resistive sensors are not the best choice for moisture sensor PCB.

This is because it exposes the electrodes to corrosion as a result of soil contact.

The corrosion also occurs as a result of direct current that flows across the moisture sensor PCB during operation.

What Are The Advantages of Capacitive Moisture Sensor PCB?

Advantages of capacitive moisture sensor PCB include the following:

  1. Allows for Easy Installation.
  2. Provides Accurate measurements and data during its operation
  3. Offer an easier way to measure vapor content consistently.
  4. Prevent the corrosion of dielectric probes or electrodes during operation.

Are There Moisture Sensor PCBs That Use LM393 Chip?

Yes, there are moisture sensor PCB designs that use LM393 Comparator IC.

Mostly, the LM393 chip is mounted on the moisture sensor PCB to serves as voltage comparator.

During operation, the comparator IC compares the threshold voltage configured utilizing the preset and moisture sensor pin.

You can set the threshold by switching the built-in potentiometer of the moisture sensor PCB.

How Many Pins Does An Analog Moisture Sensor PCB Device Have?

Analog Moisture Sensor PCB has 3 pins that forms part of its design:


This pin acts as the Power Supply Ground of the Moisture sensor PCB.


This pin powers the Moisture sensor module with about 5 volts.


Discharges the analog signal output of the Moisture Sensor Circuit Board.

What Is The Output Signal Type Of Moisture Sensor PCB?

Most modern moisture sensor PCB have two outputs, digital and analog.

Digital output is high when the moisture sensor PCB reading surpasses the configured threshold.

On the other hand, analog out relies on the moisture content of the substrate you are measuring.

How Do You Connect Moisture Sensor PCB To The Microcontroller Device?

Connecting your moisture sensor PCB is a very simple task. The module features only 3 pins which you need to link: VCC, GND and SIG.

You need to power the VCC and GND pins, and use the SIG pin to connect to the ADC pins of your microcontroller.

However, you should remember that the voltage supplied to moisture sensor PCB also impacts the value that will be displayed by the SIG.

What Is The Principle Of Operation Of Capacitive Moisture Sensor PCB?

It is common knowledge that a capacitor comprises of 3 pieces. A negative plate, a positive plate and space between plates referred to as dielectric.

There exist varying physical types of capacitors though all feature 2 metal plates and a dielectric material between them.

The operating principle of capacitive moisture sensor PCB involves establishing capacitance changes due to dielectric changes.

However, this type of moisture sensor PCB does not establish the moisture directly.

Essentially, it measures the dielectric created by the medium you are measuring.

Water is the most vital element influencing the dielectric.

A 555 timer circuitry aids in measuring the capacitance of sensor.

It produces a voltage that has direct proportionality to the capacitor sunk in the medium.

Using an analog-to-digital converter, consequently measure this voltage. It generates a value that designates the moisture percentage.

How Does The Voltage Powering Moisture Sensor PCB Affect The Output Signal?

Voltage powering Moisture Sensor PCB causes a corresponding and proportional effect on the output signal upon an electrical operation.

The level of the output signal depends on the voltage amount.

How Do You Calibrate Soil Moisture Sensor PCB?

Soil Moisture Sensor PCB Assembly

Soil Moisture Sensor PCB Assembly

Volumetric water content refers to the ratio of water volume to volume of soil in a given sample. Thus, to determine the instantaneous moisture content within a soil sample, you have to establish the mass and volume of each sample.

There will be change in the sample mass every time you add water to the soil.

You need to constantly approximate the soil moisture by maintain the volume of every sample constant every time you add water.

As you do this, you also measure the mass of each sample. This is performed by utilizing 250 ml container having graduated markings.

You should ensure the level of soil reaches similar level every time you add water to the soil.

At the beginning of the calibration process, the soil needs to be totally dry.

The appropriate way you can ensure this is by taking a few measurements of similar soil across a few hours.

When there is continuous significant change in mass, then there still may be some water evaporating.

You can settle for the dry soil mass after registering a constant mass over some few measurements.

Water density is largely known and you can work with about 997 kg/m3.

Finally, you can approximate the soil bulk density by dividing the dry mass of soil by the volume of sample.

Procedure Of Calibration

  • Measure the soil sample container mass
  • Fill the container to any volume using dry soil
  • Measure mass of the container with dry soil
  • Using 10 ml of water, wet the soil
  • Blend the wet soil about to make sure there is even distribution of the water, then refill the sample container to the chosen volume.
  • Measure the wet soil mass
  • Repeat procedures 4., 5., and 6. till there is saturation in the soil and it begins to seep water.
  • After reaching saturation, spread the wet soil on wax paper and let it dry.
  • Measure the dry soil mass, which will be the dry soil mass employed for soil density.

Is Soil Moisture Sensor PCB Compatible With Raspberry Pi?

Yes, most moisture sensor PCBs are compatible with Raspberry Pi and Arduino control boards. However, you will require an ADC converter in case you are working with a moisture sensor circuit board that is not compatible with Raspberry Pi.

Are There Digital Moisture Sensor PCBs?

Yes, there are digital moisture PCBs. They are employed when regular determination of the moisture content of soil is required.

This provides viable information needed in different stages of crop production.

Digital Moisture circuit boards basically operate by measuring the electrical resistance of the current linking two metallic electrodes.

It is most commonly used for irrigating and other agricultural processes and functions electronically with accurate readings and measurements.

What Is The Difference Between DHT11 Vs DHT22 Sensors Used In Moisture Sensor PCB?

DHT11 and DHT22 sensors are generally digital devices that measure both humidity and temperature.

These digital devices employ a thermistor and a capacitive humidity sensor on the air that surrounds a specific area. They send a signal through a data pin.

The differences between the DHT11 sensor and the DHT22 sensor include the following.

Body Size

DHT11 sensor has a body size of about 15.5mm×12mm×5.5mm in dimension as compared to the DHT22 sensor whose dimensions are 15.1mm×25mm×7.7mm in size.

Sampling Rate

The DHT11 sensor has a sampling rate of 1 hertz per second. Conversely, the DHT22 sensor has a sampling rate of 0.5 hertz per second.

Temperature Range

DHT11 sensors differ in temperature range as compared to the DHT22 sensors of Moisture sensor Circuit Boards.

The DHT11 sensor has a temperature range of 0 – 50°c /± 2°c. DHT22 sensor on the other hand has a temperature range of –40 to 80°c / 0.5°c.

Humidity Range

The difference in Humidity Range between DHT11 sensors and DHT22 sensors is significant. DHT11 sensor has a humidity range of 20 – 80 % / 5%.

The DHT22 sensor has the value of 0 – 100% / 2-5% in humidity range.

How Does DHT11/DHT22 Moisture Sensor PCB Device Work?

DHT11 Sensor

This is a cost friendly sensor that is digital and is responsible for measuring humidity and temperature.

DHT11 sensors allows for easy connection to the microcontroller for instance Arduino that is needed to instantly determine humidity and temperature.

DHT22 Sensor

This type of sensor exists as a sensor module.

The distinguishing aspect linking the two is a power LED and a resistor.

To determine the Moisture content in the air, the DHT22 employs a capacitive sensor for humidity and a thermistor.

DHT22 Sensor

DHT22 Sensor

Working Principle Of DHT11/DHT22 Moisture Sensor PCB

The DHT11/DHT22 sensor has a sensing element for measuring humidity and a thermistor for sensing temperature.

The Humidity element consists of two probes that are made up of conductive material linking the two probes.

Atoms are discharged by the conductive material as it absorbs moisture enhancing conduction of the probes.

The humidity is relatively proportional to resistance variations caused by the two probes.

In essence an increase in resistance of the two probes causes a corresponding decrease in humidity.

On the other hand, the DHT11/DHT22 sensors comprise of a thermal resistor known as a thermistor.

This device used by the Moisture sensor Circuit Board tends to change the resistance it discharges with temperature.

The change is often insignificant.

The thermistor has negative temperature quantity which can be interpreted to mean that an increase in temperature leads to a decrease in resistance.

How Many Pins Does DHT22 Sensor PCB Have?

DHT22 Moisture Sensors Circuit boards are slightly more expensive temperature and humidity sensors modules.

DHT22 sensor PCB can exist in two ways namely; as a module and as a sensor.

As a module it only has three pins and as a sensor it has four pins. The four pins in the DHT22 Sensor are detailed as follows.


This DHT22 sensor pin serves the purpose of supplying power that varies between 3.5 volts to 5.5 volts.

A 5-volt power supply is mostly prescribed with the length of the sensor being 20m.

In case a 3.3 V power supply is used, the length of cable must be 1m.

This helps in avoiding dropping of voltage resulting to inaccurate readings.

Data Pin

The data pin, mostly white or yellow is used as a communicating link from sensor to Microcontroller and vice versa.

The pin through the sequence data, is a sensor of both temperature and humidity.

NC Pin

Also known as the No Connection Pin, and is regarded of no use during operation of the DHT22 Sensor PCB.

Ground Pin

This Pin found in the DHT22 Sensor circuit board acts as a connection to the ground of the circuit.

Which Is Better Between Analog Vs. Digital Moisture Sensor PCB?

Microcontroller accepts 2 types of inputs based on the type of moisture sensor PCB, that is, digital or analog.

Analog moisture sensor PCB detects the external parameters and provide an output in the form of analog voltage.

The range of the output voltage may be from 0 to 5 Volts.

Logic Low is treated as “0” (0 to 3.5 V). On the other hand, Logic High is designated as “1” (3.5 to 5V).

Different from analog moisture sensor PCB, digital moisture sensor PCBs generate discrete results (0 and 1’s).

In digital communication, the discrete values are usually referred to as digital (binary signals.

Therefore, during selection of a moisture sensor PCB, it is essential to understand how to differentiate digital and analog circuit boards.

Analog moisture sensor PCB consist of analog components such as transistors, operational amplifiers, capacitors, diodes and resistors.

On the contrary, digital moisture sensor PCBs comprise of microcontroller chips and logic gates.

Analog signals are greatly influenced by exterior noise and produce errors within the output signal.

On the contrary, digital signals are not susceptible to noisy surrounding, this makes digital moisture sensor PCBs more preferable compared to analog ones.

For that matter, in case your application requires better throughput and accuracy opt for digital moisture sensor PCB.

However, there are some disadvantages of digital moisture sensor PCB. These modern moisture sensor modules feature low calculation range.

However, analog moisture sensor PCB feature higher calculation range. This makes them appropriate for broad humidity range and stability.

The analog moisture sensor PCB output is processed by Analog to Digital converter of microcontroller.

What Is The Operating Voltage Of Moisture Sensor PCB?

The Operating Voltage of Moisture Sensor Circuit Boards varies between 3.3 volts and 5.5 volts.

Complete Moisture Sensor PCB System

Complete Moisture Sensor PCB System

What Is The Cost Of Designing And Manufacturing Moisture Sensor PCB?

The price of moisture sensor PCB depends on several factors including the manufacturer, types of materials used, types of sensor among other factors.

However, the cost of manufacturing a piece of ODM moisture sensor PCB ranges from USD 1 to 60.

Depending on your unique requirements and specifications, Venture designs and fabricates a range of moisture PCBs for specific requirements.

Contact us today for all your moisture sensor PCB requirements.

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