Circuit Documentation

Summary

This circuit is designed to detect gas leakage using an MQ-2 gas sensor and an ESP32 microcontroller. When gas is detected above a certain threshold, a buzzer is activated, and a notification is sent via the Blynk platform. The circuit is powered by a 12V battery and includes a TP4056 module for charging a 18650 Li-Ion battery.

Component List

1. MQ-2 Gas Sensor

   • Description: Gas sensor for detecting LPG, i-butane, propane, methane, alcohol, Hydrogen, and smoke.
   • Pins: GND, VCC, ANALOG, Digital

2. ESP32 Microcontroller

   • Description: A low-power system on a chip microcontroller with integrated Wi-Fi and dual-mode Bluetooth.
   • Pins: EN, VP, VN, D34, D35, D32, D33, D25, D26, D27, D14, D12, D13, GND, VIN, 3V3, D15, D2, D4, RX2, TX2, D5, D18, D19, D21, RX0, TX0, D22, D23, BOOT

3. Buzzer

   • Description: An audio signaling device.
   • Pins: GND, IN

4. 18650 Li-Ion Battery

   • Description: Rechargeable lithium-ion battery.
   • Pins: Positive, Negative

5. TP4056 Charging Module

   • Description: Lithium battery charger module with overcharge protection.
   • Pins: OUT-, B-, B+, OUT+, IN-, IN+

6. 12V Battery

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

Wiring Details

MQ-2 Gas Sensor

• GND connected to ESP32 GND
• VCC connected to ESP32 3V3
• ANALOG connected to ESP32 D34
• Digital connected to ESP32 D35

ESP32 Microcontroller

• VIN connected to TP4056 OUT+
• GND connected to MQ-2 GND, Buzzer GND, TP4056 OUT-
• D2 connected to Buzzer IN

Buzzer

• GND connected to ESP32 GND
• IN connected to ESP32 D2

18650 Li-Ion Battery

• Positive connected to TP4056 B+
• Negative connected to TP4056 B-

TP4056 Charging Module

• OUT+ connected to ESP32 VIN
• OUT- connected to ESP32 GND
• B+ connected to 18650 Li-Ion Battery Positive
• B- connected to 18650 Li-Ion Battery Negative
• IN- connected to 12V Battery -
• IN+ connected to 12V Battery +

12V Battery

• - connected to TP4056 IN-
• + connected to TP4056 IN+

Code Documentation

#define BLYNK_TEMPLATE_ID "YourTemplateID"
#define BLYNK_DEVICE_NAME "YourDeviceName"
#define BLYNK_AUTH_TOKEN "YourAuthToken"

#include <WiFi.h>
#include <BlynkSimpleEsp32.h>

char auth[] = BLYNK_AUTH_TOKEN;
char ssid[] = "YourSSID";
char pass[] = "YourPassword";

const int gasSensorPin = 34; // Analog pin connected to MQ-2 A0
const int buzzerPin = 25;    // Digital pin connected to Buzzer Signal
const int threshold = 300;   // Threshold value for gas detection

void setup() {
  Serial.begin(115200);
  Blynk.begin(auth, ssid, pass);
  pinMode(gasSensorPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  Blynk.run();
  int gasLevel = analogRead(gasSensorPin);
  Serial.print("Gas Level: ");
  Serial.println(gasLevel);

  if (gasLevel > threshold) {
    digitalWrite(buzzerPin, HIGH);
    Blynk.notify("Gas Leakage Detected!");
  } else {
    digitalWrite(buzzerPin, LOW);
  }
}

This code initializes the ESP32 microcontroller, connects it to a Wi-Fi network, and sets up the Blynk platform for remote notifications. The gas sensor's analog output is read, and if the gas level exceeds a predefined threshold, the buzzer is activated, and a notification is sent via Blynk.