Circuit Documentation

Summary

This circuit is designed to monitor and control the environment inside an incubator. It uses a DHT22 sensor to measure temperature and humidity, a micro servo to control ventilation, a buzzer for alerts, and an Arduino UNO as the main microcontroller. Additionally, a SIM900A module is used for sending SMS alerts, and a keypad shield is included for user interaction.

Component List

1. Keypad Shield

   • Description: A shield that provides a keypad interface for user input.
   • Pins: rst, d, 5v, vin, A0, A1, A2, A3, A4, A5

2. DHT22

   • Description: A digital temperature and humidity sensor.
   • Pins: +, Out, -

3. Micro Servo 9G

   • Description: A small servo motor used for controlling ventilation.
   • Pins: GND, +5V, PWM

4. Buzzer

   • Description: An audio signaling device used for alerts.
   • Pins: PIN, GND

5. Arduino UNO

   • Description: The main microcontroller used to control the circuit.
   • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

6. SIM900A

   • Description: A GSM module used for sending SMS alerts.
   • Pins: GND, DB9-3 (RXD), DB9-2 (TXD), 5V, 3VR, 5VR, 3VT, 5VT, VCC, Ring, RESTART, RESET, STATUS

Wiring Details

Keypad Shield

• 5v connected to Arduino UNO 5V
• vin connected to Arduino UNO GND
• A0 connected to Arduino UNO A0

DHT22

• + connected to Arduino UNO 5V
• Out connected to Arduino UNO D3
• - connected to SIM900A GND

Micro Servo 9G

• GND connected to SIM900A GND
• +5V connected to SIM900A 5V
• PWM connected to Arduino UNO D11

Buzzer

• PIN connected to Arduino UNO A2
• GND connected to Arduino UNO GND

Arduino UNO

• 5V connected to DHT22 +
• GND connected to keypad shield vin
• A0 connected to keypad shield A0
• A2 connected to buzzer PIN
• D3 connected to DHT22 Out
• D11 connected to Micro Servo 9G PWM

SIM900A

• GND connected to DHT22 -
• 5V connected to Micro Servo 9G +5V

Documented Code

#include <SoftwareServo.h>
#include <LiquidCrystal.h>
#include <DHT.h>
#include <SoftwareSerial.h>

// Pins and Constants
#define DHTPIN 3
#define SERVO_PIN 13
#define BEEPER A2
#define BRIGHTNESS 12
#define TEMP_HIGH 39
#define TEMP_LOW 36
#define TEMP_ALERT_LOW 36.5
#define HUM_HIGH 75
#define HUM_LOW 50

DHT dht(DHTPIN, DHT22);
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
SoftwareServo vent;
SoftwareSerial sim900A(11, 10); // Updated to use pins (RX) (TX)

float T, H; // Temperature and Humidity
byte alarm = 0;

void setup() {
  lcd.begin(16, 2);
  lcd.print("Incubator Setup");
  delay(500);
  
  dht.begin();
  vent.attach(SERVO_PIN);
  vent.setMinimumPulse(800);
  vent.setMaximumPulse(2600);
  
  pinMode(BEEPER, OUTPUT);
  pinMode(BRIGHTNESS, OUTPUT);
  analogWrite(BRIGHTNESS, 255);
  
  sim900A.begin(9600); // Initialize SIM900A
  initializeSIM900A(); // Ensure proper initialization
  sendSMS("System Initialized: Incubator is running.");
}

void loop() {
  T = dht.readTemperature();
  H = dht.readHumidity();
  
  if (isnan(T) || isnan(H)) {
    lcd.clear();
    lcd.print("Sensor Error!");
    beep(2000, 1000);
    delay(2000);
    return;
  }
  
  lcd.setCursor(0, 0);
  lcd.print("T=");
  lcd.print(T, 1);
  lcd.print("C H=");
  lcd.print(H, 1);
  lcd.print("%");

  // Temperature and Humidity Alarm Logic
  handleAlarms();

  // Servo Position Based on Alarms
  handleServo();

  // Brightness Dimming
  analogWrite(BRIGHTNESS, 255);
  delay(2000);
}

// Functions
void handleAlarms() {
  lcd.setCursor(0, 1); // Move to the second row for alerts

  if (T > TEMP_HIGH) {
    if (!(alarm & 1)) {
      sendSMS("Alert: High temperature detected!");
      alarm |= 1;
    }
    lcd.print("High Temp!           ");
    beep(1000, 500);
  } else if (T < TEMP_ALERT_LOW) {
    if (!(alarm & 2)) {
      sendSMS("Alert: Critical low temperature detected!");
      alarm |= 2;
    }
    lcd.print("Low Temp!            ");
    beep(2000, 500);
  } else {
    alarm &= ~(1 | 2); // Clear temperature alarms
  }

  if (H > HUM_HIGH) {
    if (!(alarm & 4)) {
      sendSMS("Alert: High humidity detected!");
      alarm |= 4;
    }
    lcd.print("High Humid!          ");
    beep(1500, 500);
  } else if (H < HUM_LOW) {
    if (!(alarm & 8)) {
      sendSMS("Alert: Low humidity detected!");
      alarm |= 8;
    }
    lcd.print("Low Humid!           ");
    beep(500, 500);
  } else {
    alarm &= ~(4 | 8); // Clear humidity alarms
  }

  // Clear alert display if no alarms are active
  if (!(alarm & (1 | 2 | 4 | 8))) {
    lcd.print("Normal Temp 🙂");
  }
}

void handleServo() {
  if (T > TEMP_HIGH) {
    vent.write(0); // Open vent fully
  } else if (T < TEMP_ALERT_LOW) {
    vent.write(180); // Close vent
  } else {
    vent.write(90); // Neutral position
  }
  vent.refresh();
}

void beep(unsigned long frequency, unsigned long duration) {
  unsigned long halfPeriod = 500000 / frequency;
  unsigned long cycles = (1000 * duration) / (2 * halfPeriod);
  
  for (unsigned long i = 0; i < cycles; i++) {
    digitalWrite(BEEPER, HIGH);
    delayMicroseconds(halfPeriod);
    digitalWrite(BEEPER, LOW);
    delayMicroseconds(halfPeriod);
  }
}

void sendSMS(const char* message) {
  sim900A.println("AT"); // Wake up SIM900A
  delay(1000);
  sim900A.println("AT+CMGF=1"); // Set SMS to Text Mode
  delay(1000);
  sim900A.println("AT+CMGS=\"+639603438926\""); // Replace with your phone number
  delay(1000);
  sim900A.print(message); // SMS content
  delay(1000);
  sim900A.write(26); // ASCII code of CTRL+Z to send the SMS
  delay(5000);
}

void initializeSIM900A() {
  sim900A.println("AT"); // Test communication
  delay(1000);
  sim900A.println("AT+CSMINS?"); // Check SIM card presence
  delay(1000);
  sim900A.println("AT+CSQ"); // Check signal quality
  delay(1000);
  sim900A.println("AT+CREG?"); // Check network registration
  delay(1000);
}

This documentation provides a comprehensive overview of the circuit, including a summary, detailed component list, wiring details, and the embedded code used in the Arduino UNO.