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Soil Moisture Monitoring using ESP8266 and Soil Moisture Sensor

Hey folks

In this tutorial, we will learn how to interface LM393 module(Soil Moisture Sensor)with NodeMcu(ESP8266). LM393 is a simple water sensor can be used to detect soil moisture when the soil moisture deficit module plant waterer device, so that the plants in our garden without people to manage; Adjustable sensitivity adjust the digital potentiometer (shown in blue) Operating Voltage 3.3V-5V; Module Dual Output mode, a simple.

LM393 Soli Moisture Sensor Module(over view) 

Components Required:
  • LM393 Soil Sensor 
  • NodeMcu(ESP8266) 
  • Connecting wires(male to male) 
  • Breadboard 
Follow the Image below for circuit connection reference:-

(Interfacing all components) 

Here Pin A0 of the moisture sensor module connects to pin A0 on the ESP8266
The GND pin on the moisture sensor module connects to a GND pin on the ESP8266
The VCC pin on the moisture sensor module connects to a 3v3 pin on the ESP8266
D0 pin remain disconnected

After making the circuit dump the code given below:-

#include <ESP8266WiFi.h>
const char* ssid = "Enter SSID";
const char* password = "Enter password";
const int redPin = 4; // ~D2
const int greenPin = 12; // ~D6
const int bluePin = 14; // ~D5
int WiFiStrength = 0;
WiFiServer server(80);
void setup() {
pinMode(redPin, OUTPUT);
pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);
analogWrite(redPin, 280);
analogWrite(greenPin, 300);
analogWrite(bluePin, 300);
Serial.print("Connecting to ");
WiFi.begin(ssid, password);
//WiFi.config(IPAddress(192, 168, 1, 221), IPAddress(192, 168, 1, 1), IPAddress(255, 255, 255, 0));
while (WiFi.status() != WL_CONNECTED) {
Serial.println("WiFi connected");
Serial.println("Server started");
Serial.print("Use this URL to connect: ");

double analogValue = 0.0;
double analogVolts = 0.0;
unsigned long timeHolder = 0;
void loop() {
WiFiStrength = WiFi.RSSI();
analogValue = analogRead(A0);
analogVolts = (analogValue * 3.08) / 1024;
int chartValue = (analogValue * 100) / 400;
chartValue = 100 - chartValue;
if (millis() - 15000 > timeHolder)
{ timeHolder = millis();
if (chartValue <= 25) { // 0-25 is red "dry"
analogWrite(redPin, 1000);
analogWrite(greenPin, 0);
analogWrite(bluePin, 0);
} else if (chartValue > 25 && chartValue <= 75) // 26-75 is green
analogWrite(redPin, 0);
analogWrite(greenPin, 1000);
analogWrite(bluePin, 0);
else if (chartValue > 75 ) // 76-100 is blue
{ analogWrite(redPin, 0);
analogWrite(greenPin, 0);
analogWrite(bluePin, 1000);
delay(1000); // this is the duration the LED will stay ON
analogWrite(redPin, 0);
analogWrite(greenPin, 0);
analogWrite(bluePin, 0);
// Serial data
Serial.print("Analog raw: ");
Serial.print("Analog V: ");
Serial.print("ChartValue: ");
Serial.print("TimeHolder: ");
Serial.print("millis(): ");
Serial.print("WiFi Strength: ");
Serial.print(WiFiStrength); Serial.println("dBm");
Serial.println(" ");
delay(1000); // slows amount of data sent via serial
WiFiClient client = server.available();
if (!client) {
Serial.println("new client");
String request = client.readStringUntil('\r');
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println(""); // do not forget this one
client.println("<!DOCTYPE HTML>");
client.println(" <head>");
client.println("<meta http-equiv=\"refresh\" content=\"60\">");
client.println(" <script type=\"text/javascript\" src=\"\"></script>");
client.println(" <script type=\"text/javascript\">");
client.println(" google.charts.load('current', {'packages':['gauge']});");
client.println(" google.charts.setOnLoadCallback(drawChart);");
client.println(" function drawChart() {");
client.println(" var data = google.visualization.arrayToDataTable([ ");
client.println(" ['Label', 'Value'], ");
client.print(" ['Moisture', ");
client.println(" ], ");
client.println(" ]); ");
// setup the google chart options here
client.println(" var options = {");
client.println(" width: 400, height: 120,");
client.println(" redFrom: 0, redTo: 25,");
client.println(" yellowFrom: 25, yellowTo: 75,");
client.println(" greenFrom: 75, greenTo: 100,");
client.println(" minorTicks: 5");
client.println(" };");
client.println(" var chart = new google.visualization.Gauge(document.getElementById('chart_div'));");
client.println(" chart.draw(data, options);");
client.println(" setInterval(function() {");
client.print(" data.setValue(0, 1, ");
client.println(" );");
client.println(" chart.draw(data, options);");
client.println(" }, 13000);");
client.println(" }");
client.println(" </script>");
client.println(" </head>");
client.println(" <body>");
client.print("<h1 style=\"size:12px;\">Karkhana Soil Moisture</h1>");
// show some data on the webpage and the guage
client.print("WiFi Signal Strength: ");
client.print("Analog Raw: ");
client.print("<br>Analog Volts: ");
client.println("<br><a href=\"/REFRESH\"\"><button>Refresh</button></a>");
client.println("<div id=\"chart_div\" style=\"width: 300px; height: 120px;\"></div>");
Serial.println("Client disonnected");

After dumping the code we can check our output in the serial monitor as well as in the URL shown below:-

Output at the time of working:-

(During circuit is running)

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