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Arduino Nano Environmental Monitoring System with OLED Display and Alarm Indicators

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Circuit Documentation

Summary

This circuit is designed to monitor environmental conditions such as gas levels, dust density, temperature, and humidity. It uses an Arduino Nano microcontroller to read data from various sensors and display the information on an OLED screen. The circuit also includes LEDs and a buzzer to provide visual and auditory alerts based on predefined threshold values.

Component List

  1. Arduino Nano

    • Description: Microcontroller board based on the ATmega328P.
    • Pins: D1/TX, D0/RX, RESET, GND, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11/MOSI, D12/MISO, VIN, 5V, A7, A6, A5, A4, A3, A2, A1, A0, AREF, 3V3, D13/SCK

  2. DHT11

    • Description: Digital temperature and humidity sensor.
    • Pins: DATA, GND, VCC

  3. Buzzer

    • Description: Simple piezoelectric buzzer for sound alerts.
    • Pins: PIN, GND

  4. LED: Two Pin (red)

    • Description: Red LED for visual alerts.
    • Pins: cathode, anode

  5. LED: Two Pin (green)

    • Description: Green LED for visual alerts.
    • Pins: cathode, anode

  6. LED: Two Pin (yellow)

    • Description: Yellow LED for visual alerts.
    • Pins: cathode, anode

  7. Resistor (220 Ohms)

    • Description: Resistor to limit current through LEDs.
    • Pins: pin1, pin2
    • Properties: Resistance: 220 Ohms

  8. GP2Y1010AU0F

    • Description: Optical dust sensor.
    • Pins: VCC, Vout, S-GND, LED, LED-GND, V-LED

  9. MQ135

    • Description: Gas sensor for air quality monitoring.
    • Pins: VCC, GND, A0, D0

  10. OLED 1.3"

    • Description: OLED display for visual output.
    • Pins: GND, VCC, SCL, SDA

Wiring Details

Arduino Nano

DHT11

Buzzer

LED: Two Pin (red)

LED: Two Pin (green)

LED: Two Pin (yellow)

GP2Y1010AU0F

MQ135

OLED 1.3"

Code Documentation

// Include necessary libraries
#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>
#include <Wire.h>
#include <DHT.h>

// Pin definitions
#define MQ135_PIN A0
#define DHT_PIN 2
#define BUZZER_PIN 7
#define GREEN_LED_PIN 4
#define YELLOW_LED_PIN 5
#define RED_LED_PIN 6
#define DUST_LED_PIN 3
#define DUST_SENSOR_PIN A1

// DHT sensor setup
#define DHT_TYPE DHT11
DHT dht(DHT_PIN, DHT_TYPE);

// OLED display setup
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // OLED display

// Threshold values for alarms
const int MQ135_THRESHOLD = 300;  // Example value for gas level
const int DUST_THRESHOLD = 150;   // Example value for dust density
const float TEMP_THRESHOLD = 30.0; // Example value for temperature in °C

void setup() {
  // Initialize Serial Monitor
  Serial.begin(9600);

  // Initialize pins
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(DUST_LED_PIN, OUTPUT);

  // Initialize DHT sensor
  dht.begin();

  // Initialize OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  display.clearDisplay();

  // Start with LEDs and buzzer off
  digitalWrite(GREEN_LED_PIN, LOW);
  digitalWrite(YELLOW_LED_PIN, LOW);
  digitalWrite(RED_LED_PIN, LOW);
  digitalWrite(BUZZER_PIN, LOW);
}

void loop() {
  // Read gas level from MQ-135
  int mq135_value = analogRead(MQ135_PIN);
  Serial.print("Gas level: ");
  Serial.println(mq135_value);

  // Read dust density from GP2Y1010AU0F
  digitalWrite(DUST_LED_PIN, LOW); // Turn on IR LED for dust sensor
  delayMicroseconds(280);
  int dust_value = analogRead(DUST_SENSOR_PIN);
  delayMicroseconds(40);
  digitalWrite(DUST_LED_PIN, HIGH); // Turn off IR LED
  Serial.print("Dust density: ");
  Serial.println(dust_value);

  // Read temperature and humidity from DHT11
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  Serial.print("Temperature: ");
  Serial.println(temperature);
  Serial.print("Humidity: ");
  Serial.println(humidity);

  // Display data on OLED
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.print("Gas Level: ");
  display.println(mq135_value);
  display.print("Dust: ");
  display.println(dust_value);
  display.print("Temp: ");
  display.print(temperature);
  display.println(" C");
  display.print("Humidity: ");
  display.print(humidity);
  display.println(" %");
  display.display();

  // LED and buzzer alerts based on thresholds
  if (