Circuit Documentation

Summary

This circuit is designed to interface an Arduino UNO with multiple sensors including an HC-SR04 Ultrasonic Sensor, an IR sensor, a Humidity YL-69 sensor, an MQ-5 gas sensor, and an ESP32 microcontroller for additional processing and connectivity options. The circuit is powered by a 9V battery and includes serial communication between the Arduino UNO and the ESP32. The Arduino UNO is programmed to read data from the sensors, process the information, and communicate the sensor data to the ESP32.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• Features digital I/O pins, analog input pins, and various power options

Humidity YL-69

• Soil moisture sensor
• Outputs both analog and digital signals indicating soil moisture levels

IR Sensor

• Infrared obstacle detection sensor
• Outputs a digital signal when an obstacle is detected

MQ-5 Gas Sensor

• Gas sensor for detecting LPG, natural gas, and coal gas
• Provides both digital and analog outputs

ESP32 (30 pin)

• Microcontroller with Wi-Fi and Bluetooth capabilities
• Features a wide range of I/O pins and supports serial communication

HC-SR04 Ultrasonic Sensor (x2)

• Ultrasonic ranging module
• Provides distance measurements by emitting ultrasonic waves

9V Battery

• Provides power to the circuit

Wiring Details

Arduino UNO

• D11 PWM/MOSI connected to HC-SR04 Ultrasonic Sensor (TRIG)
• D10 PWM/SS connected to HC-SR04 Ultrasonic Sensor (ECHO)
• D9 PWM connected to second HC-SR04 Ultrasonic Sensor (TRIG)
• D8 connected to second HC-SR04 Ultrasonic Sensor (ECHO)
• D7 connected to IR Sensor (out)
• D3 PWM connected to MQ-5 Gas Sensor (Digi Out)
• D2 connected to Humidity YL-69 (D0)
• D1/TX connected to ESP32 (RX2)
• D0/RX connected to ESP32 (TX2)
• A0 connected to Humidity YL-69 (A0)
• A1 connected to MQ-5 Gas Sensor (Analog out)
• 5V connected to Humidity YL-69 (VCC), 9V Battery (-), and other components requiring 5V
• GND connected to 9V Battery (+) and other components requiring GND

Humidity YL-69

• A0 connected to Arduino UNO (A0)
• D0 connected to Arduino UNO (D2)
• GND connected to common ground
• VCC connected to 5V supply

IR Sensor

• out connected to Arduino UNO (D7)
• gnd connected to common ground
• vcc connected to 5V supply

MQ-5 Gas Sensor

• VCC connected to 5V supply
• GND connected to common ground
• Digi Out connected to Arduino UNO (D3 PWM)
• Analog out connected to Arduino UNO (A1)

ESP32 (30 pin)

• Vin connected to 5V supply
• GND connected to common ground
• TX2 connected to Arduino UNO (D0/RX)
• RX2 connected to Arduino UNO (D1/TX)

HC-SR04 Ultrasonic Sensor

• VCC connected to 5V supply
• TRIG connected to Arduino UNO (D11 PWM/MOSI or D9 PWM)
• ECHO connected to Arduino UNO (D10 PWM/SS or D8)
• GND connected to common ground

9V Battery

• + connected to common ground
• - connected to 5V supply

Documented Code

// Define pins for sensors
const int trigPin = 9;
const int echoPin = 8;
const int irPin = 7;
const int moisturePin = A0;
const int gasPin = A1;

// Setup
void setup() {
  // Start serial communication
  Serial.begin(9600);

  // Ultrasonic sensor pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // IR sensor pin
  pinMode(irPin, INPUT);

  // ESP32 communication (if needed, you can use SoftwareSerial for ESP32)
  // ESP32 communication on Serial1
  Serial1.begin(115200);
}

// Function to read Ultrasonic sensor
long readUltrasonicDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  long duration = pulseIn(echoPin, HIGH);
  long distance = duration * 0.034 / 2; // distance in cm
  return distance;
}

void loop() {
  // Read ultrasonic sensor
  long distance = readUltrasonicDistance();
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Read IR sensor
  int irValue = digitalRead(irPin);
  if (irValue == LOW) {
    Serial.println("Obstacle detected by IR sensor");
  }

  // Read Soil Moisture sensor
  int moistureValue = analogRead(moisturePin);
  Serial.print("Soil Moisture: ");
  Serial.println(moistureValue);

  // Read Chemical/Gas sensor
  int gasValue = analogRead(gasPin);
  Serial.print("Gas sensor value: ");
  Serial.println(gasValue);

  // Communicate data with ESP32 (optional)
  Serial1.println("Sending sensor data to ESP32");
  Serial1.print("Distance: ");
  Serial1.println(distance);
  Serial1.print("Soil Moisture: ");
  Serial1.println(moistureValue);
  Serial1.print("Gas sensor: ");
  Serial1.println(gasValue);

  delay(1000);
}

This code is designed to run on the Arduino UNO and handles the initialization and reading of the connected sensors. It also includes serial communication with the ESP32 for potential data transmission.