Kathmandu Valley Air Quality & Gas Monitor with ESP32 & OLED Display

Educational Notes

This project is designed to be accessible to students from Class 4 to Masters level, with complexity scalable to match different age groups and skill levels.

Learning Objectives:

• Understand basic electronics and circuitry principles
• Learn sensor applications and data collection techniques
• Develop problem-solving skills through hands-on building and troubleshooting
• Apply programming concepts to control hardware and process data
• Connect projects to real-world Nepalese contexts and challenges

Adaptability:

• For younger students (Class 4-8): Focus on assembling pre-built circuits, observing results, and understanding basic concepts
• For intermediate students (Class 9-12): Modify code, experiment with parameters, and explore underlying principles
• For advanced students (Undergraduate/Masters): Optimize designs, add features, conduct research extensions, and analyze performance

Safety Note: Always supervise younger students when working with electricity, heat, or moving parts.

Construct a compact desktop air pollution and combustible gas monitor using components available directly from Ghumti Pasal.

Hardware Breakdown (Available at Ghumti Pasal):

• Microcontroller: ESP32 Dev Module Development Board with WiFi & Bluetooth
• Gas & Smoke Sensor: Module MQ 2 Smoke methane gas liquefied flammable gas sensor module
• Climate Sensor: DHT 11 Module
• Display: 0.91 inch OLED module blue OLED 128X32 GND-VCC-SCL-SDA
• Status Ring: WS2812 Round Modules RGB LED Ring

Circuit Pinout & Wiring Connections:

Firmware Source Code (ESP32 C++)

#include <WiFi.h>
#include <HTTPClient.h>
#include <DHT.h>

#define DHTPIN 4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

const char* wifiSSID = "GhumtiPasal_WiFi";
const char* wifiPass = "NepalMakers2026";
const char* serverApiUrl = "http://api.ghumtipasal.com.np/v1/telemetry";

void setup() {
  Serial.begin(115200);
  Serial.println("Initializing Environmental & Microclimate Telemetry Node...");
  dht.begin();

  WiFi.begin(wifiSSID, wifiPass);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi Connected to GhumtiPasal Network!");
}

void loop() {
  float temp = dht.readTemperature();
  float humidity = dht.readHumidity();

  if (isnan(temp) || isnan(humidity)) {
    Serial.println("ERROR: Failed to read data from DHT sensor!");
    delay(2000);
    return;
  }

  Serial.printf("Telemetry Update -> Temp: %.1f C | Humidity: %.1f %%
", temp, humidity);

  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    http.begin(serverApiUrl);
    http.addHeader("Content-Type", "application/json");
    String jsonBody = "{\"temp\":" + String(temp) + ",\"humidity\":" + String(humidity) + "}";
    int httpResponseCode = http.POST(jsonBody);
    Serial.printf("HTTP Server Response: %d
", httpResponseCode);
    http.end();
  }

  delay(5000);
}