Different plants need different types of soil with different nutrient values. This is determined by testing the soil type. That is a long process of sending the soil sample to the lab and it needs a testing period of two days.  Information about the soil is to be deducted using the number of sensors connected with the node MCU using the Blynk app integration. This will reduce the large amount of time that is used for testing the soil nature.

      Soil moisture sensors measure the volumetric water content In soil. Since the direct gravimetric measurement of free soil moisture requires removing, drying, and weighing of a sample, soil moisture sensors measure the volumetric water content indirectly by using some other properties of the soil, such as PH, moisture, Temperature, Humidity sensors as a proxy for the moisture content.

         The relation between the measured property and soil moisture must be calibrated and may vary depending on environmental factors such as soil type, temperature, or electric conductivity. Reflected microwave radiation is affected by soil moisture and is used for remote sensing In hydrology and agriculture. Portable probe instruments can be used by farmers or gardeners.

           Soil moisture sensors typically refer to sensors that estimate volumetric water content. Another class of sensors measures another property of moisture in soils called water potential; these sensors are usually referred to as soil water potential sensors and include tensiometers and gypsum blocks.

COMPONENTS:

1. DHT11 :

Humidity is the measure of water vapor present in the air. The level of humidity in air affects various physical, chemical, and biological processes.  In industrial applications, humidity can affect the business cost of the products, health, and safety of the employees. So, in semiconductor industries and control system industries measurement of humidity is very important.  Humidity measurement determines the amount of moisture present in the gas that can be a mixture of water vapor, nitrogen, argon or pure gas, etc…  Humidity sensors are of two types based on their measurement units.  They are a relative humidity sensor and an Absolute humidity sensor. DHT11 is a digital temperature and humidity sensor.DHT11 is a low-cost digital sensor for sensing temperature and humidity.  This sensor can be easily interfaced with any microcontroller such as Arduino, Raspberry Pi, etc… to measure humidity and temperature instantaneously.

DHT11 humidity and temperature sensor are available as a sensor and as a module. The difference between this sensor and module is the pull-up resistor and a power-on LED. DHT11 is a relative humidity sensor.  To measure the surrounding air this sensor uses a thermistor and a capacitive humidity sensor.

2. PH Board :

Soil pH meters are devices used by home gardeners and agricultural professionals to measure the acidity or alkalinity of the soil. Getting your soil pH right is a must if you want to produce healthy, vibrant plants.To get accurate measurements you need to know the right procedure for your soil pH meter. Soil pH meters are devices used to measure the acidity or alkalinity of soil. They work by measuring the hydrogen ion activity and this is expressed through the potential for hydrogen or ‘pH’. The pH scale ranges from 0 – 14 with 0 being extremely acidic, 7 being neutral and 14 being alkaline. The ideal pH range for most plants falls between 5.5 and 7.5. Although, some plants are still able to thrive outside of this range. Soil pH affects the uptake of key nutrients, so when pH is out of the ideal range there is a chance your plants and crops are not having optimum nutrient uptake and therefore not reaching their full growth potential. Soil pH can be affected by many things. The most common influences on soil pH are weather, fertilizer, type and amount of irrigation, soil type, other plants in the area, and nutrient availability. This means soil pH can change considerably and it is absolutely essential to take regular measurements using a soil pH meter to ensure healthy growing plants.

3. SOIL MOISTURE SENSOR

The moisture of the soil plays an essential role in the irrigation field as well as in gardens for plants. As nutrients in the soil provide food to the plants for their growth. Supplying water to the plants is also essential to change the temperature of the plants. The temperature of the plant can be changed with water using a method like transpiration. And plant root systems are also developed better when rising within moist soil. Extreme soil moisture levels can guide to anaerobic situations that can encourage the plant’s growth as well as soil pathogens. This article discusses an overview of the soil moisture sensor, its working, and its applications. The soil moisture sensor is one kind of sensor used to gauge the volumetric content of water within the soil. As the straight gravimetric dimension of soil moisture needs eliminating, drying, as well as sample weighting. These sensors measure the volumetric water content not directly with the help of some other rules of soil like dielectric constant, electrical resistance, otherwise interaction with neutrons, and replacement of the moisture content. The relation among the calculated property as well as moisture of soil should be adjusted & may change based on ecological factors like temperature, type of soil, otherwise electric conductivity. The microwave emission which is reflected can be influenced by the moisture of soil as well as mainly used in agriculture and remote sensing within hydrology.

WORKING:

When you hear the term ‘smart garden’, one of the things that comes to your mind is a system that measures soil moisture and irrigates your plants automatically.

With this type of system, you can water your plants only when needed and avoid over-watering or under-watering.

If you want to build such a system then you will definitely need a Soil Moisture Sensor.

AO (Analog Output) pin gives us an analog signal between the supply value to 0V and will be connected to one of the analog inputs on your Arduino.

DO (Digital Output) pin gives Digital output of internal comparator circuit. You can connect it to any digital pin on an Arduino or directly to a 5V relay or similar device.

VCC pin supplies power for the sensor. It is recommended to power the sensor with between 3.3V – 5V. Please note that the analog output will vary depending on what voltage is provided for the sensor.

GND is a ground connection

To get accurate readings out of your soil moisture sensor, it is recommended that you first calibrate it for the particular type of soil that you plan to monitor.