🌱 Smart Plant Monitoring + Automatic Watering System

Using ESP32 + Soil Moisture Sensor + Relay + Water Pump

ESP32 Wifi Terminal Code + VERY detailed line-by-line explanation.

✅ ESP32 connects to your Home WiFi
✅ Mobile also connected to same WiFi
✅ Open WiFi Terminal App (TCP Client)
✅ Enter ESP32 IP + Port
✅ You get live terminal output
✅ Moisture < 10% → Pump ON
✅ Moisture ≥ 10% → Pump OFF

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✅ 1) WiFi Terminal App (Android)

Use any one:

📱 TCP Telnet Terminal
📱 Telnet Client
📱 Serial WiFi Terminal

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✅ 2) ESP32 WiFi Router Mode WiFi Terminal Code (COPY-PASTE)

⚡ Connections:

• Soil Sensor AO → GPIO34

• Relay IN → GPIO26

🔧 Change your WiFi name + password below.

/************************************************************
SMART PLANT MONITORING + AUTO WATERING SYSTEM (WiFi Router)
Board: ESP32
Sensor: Soil Moisture Sensor (Analog)
Relay: 1 Channel Relay
Pump: DC Water Pump

Condition:
Moisture < 10% -> Pump ON
Moisture >= 10% -> Pump OFF

Output:
Serial Monitor + WiFi Terminal App (TCP)
************************************************************/

#include <WiFi.h>

// ----------- Your Running WiFi Details -----------
const char* ssid = "YOUR_WIFI_NAME";
const char* password = "YOUR_WIFI_PASSWORD";

// ----------- TCP Server Port -----------
WiFiServer server(23); // Port 23 (Telnet)

WiFiClient client;

// ----------- Pin Definitions -----------
#define SOIL_SENSOR_PIN 34
#define RELAY_PIN 26

// ----------- Moisture Calibration Values -----------
int dryValue = 3500;
int wetValue = 1500;

// ----------- Moisture Threshold -----------
int pumpThreshold = 10;

// ----------- Variables -----------
int sensorValue = 0;
int moisturePercent = 0;
String soilStatus = "";
String pumpStatus = "";

// ----------- Function: Read sensor + control pump -----------
void readSensorAndControlPump()
{
// Read ADC from soil sensor
sensorValue = analogRead(SOIL_SENSOR_PIN);

// Convert ADC to moisture %
moisturePercent = map(sensorValue, dryValue, wetValue, 0, 100);

// Clamp moisture % (0-100)
if (moisturePercent > 100) moisturePercent = 100;
if (moisturePercent < 0) moisturePercent = 0;

// Pump control
if (moisturePercent < pumpThreshold)
{
// Soil dry -> Pump ON
digitalWrite(RELAY_PIN, LOW); // Active LOW relay
soilStatus = "DRY";
pumpStatus = "ON";
}
else
{
// Soil ok -> Pump OFF
digitalWrite(RELAY_PIN, HIGH);
soilStatus = "OK";
pumpStatus = "OFF";
}
}

void setup()
{
Serial.begin(115200);

pinMode(RELAY_PIN, OUTPUT);

// Pump OFF initially
digitalWrite(RELAY_PIN, HIGH);

// ----------- Connect ESP32 to Running WiFi -----------
Serial.println("Connecting to WiFi...");
WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}

Serial.println("\n=======================================");
Serial.println("WiFi Connected Successfully!");
Serial.print("WiFi Name: ");
Serial.println(ssid);
Serial.print("ESP32 IP Address: ");
Serial.println(WiFi.localIP());
Serial.println("TCP Port: 23");
Serial.println("=======================================");

// Start TCP Server
server.begin();
server.setNoDelay(true);
}

void loop()
{
// ----------- Step 1: Accept new client connection -----------
if (!client || !client.connected())
{
client = server.available();

if (client)
{
Serial.println("New WiFi Terminal Client Connected!");

client.println("=======================================");
client.println("SMART PLANT MONITORING + AUTO WATERING");
client.println("WiFi Terminal Connected Successfully!");
client.println("Condition: Moisture < 10% => Pump ON");
client.println("=======================================");
}
}

// ----------- Step 2: Read sensor and control pump -----------
readSensorAndControlPump();

// ----------- Step 3: Create output message -----------
String message = "";
message += "ADC: ";
message += sensorValue;
message += " | Moisture: ";
message += moisturePercent;
message += "%";
message += " | Soil: ";
message += soilStatus;
message += " | Pump: ";
message += pumpStatus;

// ----------- Step 4: Print to Serial Monitor -----------
Serial.println(message);

// ----------- Step 5: Send to WiFi Terminal App -----------
if (client && client.connected())
{
client.println(message);
}

// ----------- Step 6: Delay -----------
delay(1000);
}

✅ 3) How To Use (Step-by-Step)

Step 1:

Replace:

With your actual WiFi details.

Example:

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Step 2:

Upload code to ESP32.

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Step 3:

Open Serial Monitor (115200)

You will see ESP32 IP like:

---

Step 4:

Connect your mobile to same WiFi.

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Step 5:

Open WiFi Terminal App

Set:

• IP = ESP32 IP (example 192.168.29.112)

• Port = 23

Press Connect.

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Step 6:

You will see live output like:

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✅ 4) FULL DETAILED CODE EXPLANATION (Line-by-Line)

Now complete explanation.

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✅ A) WiFi Library

This library allows ESP32 to connect to WiFi router.

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✅ B) WiFi Credentials

ESP32 uses this to connect to your home WiFi.

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✅ C) TCP Server Setup

• server(23) creates a TCP server on port 23

• client stores the connected mobile device

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✅ D) Pins

• GPIO34 reads analog soil sensor

• GPIO26 controls relay

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✅ E) Calibration

Used for moisture percentage.

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✅ F) Threshold

If moisture < 10% pump ON.

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✅ G) readSensorAndControlPump() Function

This function is made to keep code clean.

It does:

1) Read ADC

Reads soil sensor value (0-4095)

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2) Convert to Moisture %

Converts ADC to percentage.

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3) Clamp

Fix range.

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4) Pump logic

If moisture less than 10% → soil dry.

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Pump ON

Active LOW relay means LOW = ON.

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Pump OFF

HIGH = OFF.

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✅ H) setup() Explanation

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Serial Start

Starts Serial Monitor.

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Relay setup

Pump OFF initially.

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Connect to WiFi

ESP32 tries to connect.

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Wait until connected

This loop keeps waiting until WiFi connects.

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Print IP

This prints the router network IP.

Example:
192.168.29.112

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Start server

Starts TCP server.

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✅ I) loop() Explanation

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Accept client

If a phone connects, this returns a client.

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Welcome message

This message appears in WiFi terminal.

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Read sensor + control pump

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Build output message

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Print to serial

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Send to WiFi terminal

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Delay

Update every 1 second.

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✅ 5) IMPORTANT NOTES

✅ 1) Mobile and ESP32 must be on SAME WiFi

Otherwise app will not connect.

✅ 2) Port 23 should not be blocked

Some routers block port 23.
If that happens, use port 8080.

If you want I can give port 8080 version too.