Project Documentation

ESP32-Based Environmental Monitoring and Water Management System

Circuit Documentation

Summary

The circuit is designed to monitor and control various environmental parameters for an application such as a greenhouse or aquarium. It includes sensors for measuring temperature, humidity, light intensity, water level, pH, and total dissolved solids (TDS). Actuators in the circuit include relays for controlling lights, a fan, water pumps, and solenoid valves. The central control unit is an ESP32 microcontroller, which processes sensor data and manages the actuators accordingly.

Component List

DHT22: A sensor for measuring temperature and humidity.
PH Meter: A sensor for measuring the pH level of a solution.
BH1750: A light intensity sensor.
HC-SR04 Ultrasonic Sensor: A sensor for measuring water level by ultrasonic distance measurement.
TDS Sensor: A sensor for measuring the total dissolved solids in water.
Water Pump: A pump for moving water.
1-Channel Relay (5V 10A): A relay module for controlling high power devices.
Green Light 220VAC: An indicator light for signaling system status.
220V Fan: A fan for air circulation.
Plastic Solenoid Valve: A valve for controlling the flow of liquids.
AC Supply: Provides alternating current power supply.
HLK-PM12: A compact power module to convert AC to DC voltage.
6 Relays Module: A module with multiple relays for controlling various devices.
ESP32 Wroom: A microcontroller with Wi-Fi capabilities for controlling and monitoring the system.

Wiring Details

DHT22

VCC: Connected to 3.3V from ESP32.
GND: Connected to ground.
DAT: Connected to GPIO4 on ESP32.

PH Meter

VCC: Connected to 3.3V from ESP32.
GND: Connected to ground.
Signal: Connected to GPIO34 on ESP32.

BH1750

VCC: Connected to 3.3V from ESP32.
GND: Connected to ground.
SCL: Connected to GPIO22 (SCL) on ESP32.
SDA: Connected to GPIO21 (SDA) on ESP32.

HC-SR04 Ultrasonic Sensor

VCC: Connected to 5V from ESP32.
TRIG: Connected to GPIO27 on ESP32.
ECHO: Connected to GPIO12 on ESP32.
GND: Connected to ground.

TDS Sensor

Signal: Connected to GPIO32 on ESP32.

Water Pump

VCC: Controlled by NO pin of a 1-Channel Relay.
GND: Connected to ground.

1-Channel Relay (5V 10A)

VCC: Connected to 5V from ESP32.
GND: Connected to ground.
Signal: Controlled by various GPIOs on ESP32.

Green Light 220VAC

+: Controlled by NO pin of a 1-Channel Relay.
-: Connected to AC Supply negative.

220V Fan

L: Controlled by NO pin of a 1-Channel Relay.
N: Connected to AC Supply negative.

Plastic Solenoid Valve

Pin1: Controlled by NO pins of the 6 Relays Module.
Pin2: Connected to ground.

AC Supply

+ve: Connected to C pin of 1-Channel Relays and HLK-PM12 AC pin.
-ve: Connected to ground and HLK-PM12 AC pin.

HLK-PM12

+V0: Connected to VCC of 6 Relays Module.
-V0: Connected to ground.
AC: Connected to AC Supply.

6 Relays Module

VCC: Connected to +V0 from HLK-PM12.
GND: Connected to ground.
IN1-IN6: Controlled by various GPIOs on ESP32.
NO_1-NO_6: Control various actuators like solenoid valves and water pumps.
COM_1-COM_6: Connected to +V0 from HLK-PM12.

Documented Code

#include "DHT.h"
#include <Wire.h>
#include <BH1750.h>

// DHT22 Sensor
#define DHTPIN 4       // Pin where the DHT22 is connected (GPIO 4)
#define DHTTYPE DHT22  // DHT22 sensor type
DHT dht(DHTPIN, DHTTYPE);

// Light Intensity Sensor
BH1750 lightMeter;
#define LIGHT_RELAY 17 // Relay pin for light bulbs

// Water Level Sensor
#define TRIGPIN 27     // Ultrasonic sensor trigger pin
#define ECHOPIN 12     // Ultrasonic sensor echo pin
#define WATER_RELAY 18 // Relay pin for water level

// pH Sensor
#define PH_PIN 34      // Analog pin for pH sensor
#define PH_RELAY 13    // Relay pin for pH control

// TDS Sensor
#define TDS_PIN 32     // Analog pin for TDS sensor
#define TDS_RELAY_1 25 // Relay pin for solenoid valve 1
#define TDS_RELAY_2 26 // Relay pin for solenoid valve 2

// Main Water Pump
#define PUMP_RELAY 14  // Relay pin for main water pump

// Temperature and Humidity Thresholds
float tempThreshold = 30.0;        // Temperature threshold for fan
float humidityThreshold = 40.0;    // Humidity threshold for misters

// Light Intensity Threshold
float lightThreshold = 200.0;      // Light intensity threshold (lux)

// Water Level Threshold
const float WATER_LEVEL_THRESHOLD = 300.0;  // Water level threshold (mm)

// pH Threshold
const float PH_THRESHOLD = 6.5;    // pH threshold value

// TDS Threshold
const int thresholdTDS = 300;      // TDS threshold value

// Main Pump Timing
unsigned long previousMillis = 0;
const long onInterval = 2000;      // Pump ON time (ms)
const long offInterval = 3000;     // Pump OFF time (ms)
bool pumpState = false;            // Main pump state

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

  // Initialize DHT22
  dht.begin();

  // Initialize Light Sensor
  Wire.begin();
  lightMeter.begin();

  // Relay Pins Setup
  pinMode(LIGHT_RELAY, OUTPUT);
  pinMode(WATER_RELAY, OUTPUT);
  pinMode(PH_RELAY, OUTPUT);
  pinMode(TDS_RELAY_1, OUTPUT);
  pinMode(TDS_RELAY_2, OUTPUT);
  pinMode(PUMP_RELAY, OUTPUT);

  // Set relays to OFF (assume active LOW relays)
  digitalWrite(LIGHT_RELAY, HIGH);
  digitalWrite(WATER_RELAY, HIGH);
  digitalWrite(PH_RELAY, HIGH);
  digitalWrite(TDS_RELAY_1, HIGH);
  digitalWrite(TDS_RELAY_2, HIGH);
  digitalWrite(PUMP_RELAY, HIGH);

  // Water Level Sensor Pins
  pinMode(ECHOPIN, INPUT);
  pinMode(TRIGPIN, OUTPUT);
}

void loop() {
  // --- DHT22 Sensor ---
  float temp = dht.readTemperature();
  float humidity = dht.readHumidity();

  if (!isnan(temp) && !isnan(humidity)) {
    Serial.print("Temperature: ");
    Serial.println(temp);
    Serial.print("Humidity: ");
    Serial.println(humidity);

    // Fan control based on temperature
    if (temp > tempThreshold) {
      Serial.println("Fan ON");
      digitalWrite(PUMP_RELAY, LOW); // Fan ON (active low)
    } else {
      Serial.println("Fan OFF");
      digitalWrite(PUMP_RELAY, HIGH); // Fan OFF
    }

    // Misters control based on humidity
    if (humidity < humidityThreshold) {
      Serial.println("Misters ON");
      digitalWrite(PUMP_RELAY, LOW); // Misters ON (active low)
    } else {
      Serial.println("Misters OFF");
      digitalWrite(PUMP_RELAY, HIGH); // Misters OFF
    }
  }

  // --- Light Intensity Sensor ---
  float lux = lightMeter.readLightLevel();
  Serial.print("Light Intensity: ");
  Serial.println(lux);

  if (lux < lightThreshold) {
    Serial.println("LED Bulbs ON");
    digitalWrite(LIGHT_RELAY, LOW); // Turn on LED bulbs
  } else {
    Serial.println("LED Bulbs OFF");
    digitalWrite(LIGHT_RELAY, HIGH); // Turn off LED bulbs
  }

  // --- Water Level Sensor ---
  digitalWrite(TRIGPIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGPIN, HIGH);
  delayMicroseconds(30);
  digitalWrite(TRIGPIN, LOW);

  long duration = pulseIn(ECHOPIN, HIGH);
  float distance = (duration / 2.0) * 0.343;
  
  Serial.print("Water Level Distance: ");
  Serial.println(distance);

  if (distance > WATER_LEVEL_THRESHOLD) {
    Serial.println("Water Level Low: Solenoid ON");
    digitalWrite(WATER_RELAY, LOW