Circuit Documentation

Summary

This circuit is designed to detect light using an LDR sensor. If no light is detected, it turns on an LED and rotates a motor clockwise. If light is detected, it turns off the LED and rotates the motor counter-clockwise. The system also detects temperature and humidity using a DHT11 sensor and displays this data on an LCD screen and an IoT system using ESP32. The motor can also be controlled via the IoT system, and temperature and humidity data can be viewed remotely.

Component List

1. Arduino UNO

   • Description: Microcontroller board based on the ATmega328P.
   • 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

2. L298N DC Motor Driver

   • Description: Dual H-Bridge motor driver.
   • Pins: OUT1, OUT2, 12V, GND, 5V, OUT3, OUT4, 5V-ENA-JMP-I, 5V-ENA-JMP-O, +5V-J1, +5V-J2, ENA, IN1, IN2, IN3, IN4, ENB

3. DHT11 Humidity and Temperature Sensor

   • Description: Digital sensor for measuring temperature and humidity.
   • Pins: VDD, DATA, NULL, GND

4. Hobby Gearmotor with 48:1 Gearbox

   • Description: Small DC motor with a 48:1 gearbox.
   • Pins: pin 1, pin 2

5. 9V Battery

   • Description: Power source for the circuit.
   • Pins: -, +

6. 16x2 I2C LCD

   • Description: LCD display with I2C interface.
   • Pins: GND, VCC, SDA, SCL

7. LED: Two Pin (red)

   • Description: Red LED.
   • Pins: cathode, anode

8. Resistor

   • Description: 220 Ohms resistor.
   • Pins: pin1, pin2
   • Properties: Resistance: 220 Ohms

9. ESP32 (30 pin)

   • Description: Wi-Fi and Bluetooth microcontroller.
   • Pins: EN, VP, VN, D34, D35, D32, D33, D25, D26, D27, D14, D12, D13, GND, Vin, D23, D22, TX0, RX0, D21, D19, D18, D5, TX2, RX2, D4, D2, D15, 3V3

10. Module LDR

    • Description: Light-dependent resistor module.
    • Pins: VCC, GND, DO, AO

Wiring Details

Arduino UNO

• GND connected to:

  • LED: Two Pin (red) cathode
  • DHT11 Humidity and Temperature Sensor GND
  • Module LDR GND
  • L298N DC Motor Driver GND
  • 16x2 I2C LCD GND
  • ESP32 (30 pin) GND
  • 9V Battery -

• 5V connected to:

  • DHT11 Humidity and Temperature Sensor VDD
  • Module LDR VCC
  • L298N DC Motor Driver 12V
  • L298N DC Motor Driver ENB
  • L298N DC Motor Driver ENA
  • 16x2 I2C LCD VCC
  • ESP32 (30 pin) Vin

• Vin connected to 9V Battery +

• D2 connected to DHT11 Humidity and Temperature Sensor DATA

• A0 connected to Module LDR AO

• A4 connected to 16x2 I2C LCD SDA

• A5 connected to 16x2 I2C LCD SCL

• D7 connected to Resistor pin2

• D6 connected to L298N DC Motor Driver IN4

• D5 connected to L298N DC Motor Driver IN3

• D4 connected to L298N DC Motor Driver IN2

• D3 connected to L298N DC Motor Driver IN1

• D1 connected to ESP32 (30 pin) RX0

• D0 connected to ESP32 (30 pin) TX0

L298N DC Motor Driver

• OUT1 connected to Hobby Gearmotor with 48:1 Gearbox pin 1

• OUT2 connected to Hobby Gearmotor with 48:1 Gearbox pin 2

LED: Two Pin (red)

• anode connected to Resistor pin1

Resistor

• pin2 connected to Arduino UNO D7

Code Documentation

Arduino UNO Code

/*
 * This Arduino sketch is for a system that detects light using an LDR sensor.
 * If no light is detected, it turns on an LED and rotates a motor clockwise.
 * If light is detected, it turns off the LED and rotates the motor counter-
 * clockwise. The system also detects temperature and humidity using a DHT11
 * sensor and displays this data on an LCD screen and an IoT system using ESP32.
 * The motor can also be controlled via the IoT system, and temperature and
 * humidity data can be viewed remotely.
 */

#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define DHTPIN 2
#define DHTTYPE DHT11
#define LDRPIN A0
#define LEDPIN 7
#define IN1 3
#define IN2 4
#define IN3 5
#define IN4 6

DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  pinMode(LEDPIN, OUTPUT);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
  lcd.begin();
  lcd.backlight();
  dht.begin();
  Serial.begin(115200);
}

void loop() {
  int ldrValue = analogRead(LDRPIN);
  float h = dht.readHumidity();
  float t = dht.readTemperature();

  if (ldrValue < 500) {
    digitalWrite(LEDPIN, HIGH);
    rotateMotorClockwise();
  } else {
    digitalWrite(LEDPIN, LOW);
    rotateMotorCounterClockwise();
  }

  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(t);
  lcd.print(" C");
  lcd.setCursor(0, 1);
  lcd.print("Humidity: ");
  lcd.print(h);
  lcd.print(" %");

  sendToESP32(t, h);
  delay(2000);
}

void rotateMotorClockwise() {
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
}

void rotateMotorCounterClockwise() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
}

void sendToESP32(float temperature, float humidity) {
  Serial.print("Temp:");
  Serial.print(temperature);
  Serial.print(", Humidity:");
  Serial.println(humidity);
}

ESP32 Code

void setup() {
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
}

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