Circuit Documentation

Summary

The circuit in question is designed to monitor environmental conditions and control a water pump and fans based on temperature and water level readings. It utilizes an Arduino Mega 2560 as the main microcontroller to interface with a DHT22 temperature and humidity sensor, a water level sensor, and a 2-channel relay module. The relay module controls the power to a water pump and two 120mm 12V fans. An ESP32 microcontroller is also included for potential WiFi capabilities. The system is powered by a 12V battery.

Component List

Arduino Mega 2560

• Microcontroller board based on the ATmega2560
• Provides numerous digital input/output pins, analog inputs, and PWM outputs
• Includes communication interfaces such as UART, SPI, and I2C

DHT22

• Digital temperature and humidity sensor
• Provides calibrated digital output

Water Level Sensor

• Sensor for measuring the level of water
• Outputs an analog signal corresponding to the water level

2-Channel Relay Module

• Module with two relays capable of controlling high power devices
• Each relay has Normally Open (NO) and Normally Closed (NC) connections

12V Battery (Small Size)

• Provides power to the circuit
• 12V output suitable for the fans and water pump

Water Pump

• Electric pump for moving water
• Operates at 12V

120mm Fan 12V

• Two 120mm fans for air circulation
• Operates at 12V

ESP32 (30 Pin)

• Microcontroller with WiFi capability
• Provides a variety of digital and analog I/O pins

Wiring Details

Arduino Mega 2560

• 5V pin connected to the VCC pins of the DHT22, Water Level Sensor, and 2ch relay
• GND pin connected to the GND pins of the DHT22, Water Level Sensor, and 2ch relay
• D2 PWM pin connected to the DAT pin of the DHT22
• A0 pin connected to the SIG pin of the Water Level Sensor
• D3 PWM pin connected to the IN1 pin of the 2ch relay (controls the water pump)
• D4 PWM pin connected to the IN2 pin of the 2ch relay (controls the fans)
• 3V3 pin connected to the 3V3 pin of the ESP32
• GND pin connected to the GND pin of the ESP32
• D19/RX1 pin connected to the TX0 pin of the ESP32 (for serial communication)
• D18/TX1 pin connected to the RX0 pin of the ESP32 (for serial communication)

DHT22

• VCC pin connected to the 5V of the Arduino Mega 2560
• GND pin connected to the GND of the Arduino Mega 2560
• DAT pin connected to the D2 PWM of the Arduino Mega 2560

Water Level Sensor

• VCC pin connected to the 5V of the Arduino Mega 2560
• GND pin connected to the GND of the Arduino Mega 2560
• SIG pin connected to the A0 of the Arduino Mega 2560

2-Channel Relay Module

• VCC pin connected to the 5V of the Arduino Mega 2560
• GND pin connected to the GND of the Arduino Mega 2560
• IN1 pin connected to the D3 PWM of the Arduino Mega 2560
• IN2 pin connected to the D4 PWM of the Arduino Mega 2560
• COM pins connected to the VCC of the 12V Battery
• NO pins connected to the VCC of the Water Pump and one of the 120mm fans

12V Battery (Small Size)

• VCC pin connected to the COM pins of the 2ch relay
• GND pin connected to the GND pins of the Water Pump and the 120mm fans

Water Pump

• VCC pin connected to the NO pin of the 2ch relay
• GND pin connected to the GND of the 12V Battery

120mm Fans 12V

• One fan's 12V+ pin connected to the NO pin of the 2ch relay, and the other fan's 12V+ pin connected to the 12V+ of the first fan
• Both fans' GND pins connected to the GND of the 12V Battery

ESP32 (30 Pin)

• 3V3 pin connected to the 3V3 of the Arduino Mega 2560
• GND pin connected to the GND of the Arduino Mega 2560
• TX0 pin connected to the D19/RX1 of the Arduino Mega 2560
• RX0 pin connected to the D18/TX1 of the Arduino Mega 2560

Documented Code

Arduino Mega 2560 Code (SYSTEM.ino)

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

#define DHTPIN 2
#define DHTTYPE DHT22
#define WATER_LEVEL_PIN A0
#define RELAY_PUMP_PIN 3
#define RELAY_FAN_PIN 4

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  Serial1.begin(115200); // Communication with ESP32
  dht.begin();
  
  pinMode(WATER_LEVEL_PIN, INPUT);
  pinMode(RELAY_PUMP_PIN, OUTPUT);
  pinMode(RELAY_FAN_PIN, OUTPUT);
  
  digitalWrite(RELAY_PUMP_PIN, LOW);
  digitalWrite(RELAY_FAN_PIN, LOW);
}

void loop() {
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  int waterLevel = analogRead(WATER_LEVEL_PIN);
  
  // Send data to ESP32
  Serial1.print("Temperature: ");
  Serial1.print(temperature);
  Serial1.print(" C, Humidity: ");
  Serial1.print(humidity);
  Serial1.print(" %, Water Level: ");
  Serial1.print(waterLevel);
  Serial1.println(" mm");
  
  // Check if the temperature is below 15 degrees Celsius
  if (temperature < 15.0 && waterLevel > 3) {
    digitalWrite(RELAY_PUMP_PIN, HIGH); // Activate water pump
    digitalWrite(RELAY_FAN_PIN, HIGH);  // Activate fans
  } else {
    digitalWrite(RELAY_PUMP_PIN, LOW);  // Deactivate water pump
    digitalWrite(RELAY_FAN_PIN, LOW);   // Deactivate fans
  }
  
  delay(2000); // Wait for 2 seconds before the next reading
}

ESP32 Code (sketch.ino)

#include <WiFi.h>
#include <WebServer.h>

const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

WebServer server(80);

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  
  Serial.println("Connected to WiFi");
  
  server.on("/", handleRoot);
  server.begin();
}

void loop() {
  server.handleClient();
}

void handleRoot() {
  if (Serial.available()) {
    String data = Serial.readStringUntil('\n');
    server.send(200, "text/plain", data);
  } else {
    server.send(200, "text/plain", "No data available");
  }
}

(Note: The second code snippet provided for the Arduino Mega 2560 appears to be intended for the ESP32, as it includes WiFi library calls and is written in C++ which is typical for ESP32 sketches. The code snippet is similar to the ESP32 code provided, suggesting a possible duplication or mislabeling in the input data.)