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--- iothings:proiecte:2025sric:airquality [2025/05/28 21:59]
ion_andrei.toader [Code Snippet]
+++ iothings:proiecte:2025sric:airquality [2025/05/28 22:29] (current)
ion_andrei.toader [Web Application]
@@ Line 150: / Line 150: @@
 ====== Software Description ======
-The Air Sense Visualizer is a web application created to monitor and display air quality data in real time. It retrieves sensor readings—such as PPM values from an air quality sensor—and presents them through a clean, user-friendly interface. The application is designed for development and educational use, offering a simple way to test, view, and analyze environmental data either locally or through connection with cloud-based platforms. Its structure is modular and flexible, making it easy to adapt to different use cases and hardware setups.
+The Air Quality is a web application created to monitor and display air quality data in real time. It retrieves sensor readings such as PPM values from an air quality sensor—and presents them through a clean, user-friendly interface. The application is designed for development and educational use, offering a simple way to test, view, and analyze environmental data either locally or through connection with cloud-based platforms. Its structure is modular and flexible, making it easy to adapt to different use cases and hardware setups.
 ===== Code Snippet =====
   * Wi-Fi & Firebase Initialization
+This part connects to Wi-Fi and initializes Firebase for anonymous sign-in and Realtime Database communication.
 <code>
@@ Line 192: / Line 193: @@
 }
+</code>
+  * Sensor Reading & Conversion
+Reads the analog value from the MQ-135 sensor, calculates Rs, and then converts that to a PPM (parts per million) estimate using a logarithmic formula.
+<code>
+#define MQ135_PIN 34
+#define RZERO 116404.0
+#define RL_VALUE 10000.0
+#define PARA 116.6020682
+#define PARB -2.769034857
+void loop() {
+  int adcValue = analogRead(MQ135_PIN);
+  float sensor_voltage = adcValue * (3.3 / 4095.0);
+  float rs = (3.3 - sensor_voltage) * RL_VALUE / sensor_voltage;
+  float ratio = rs / RZERO;
+  float ppm = PARA * pow(ratio, PARB);
+}
 </code>
+  * Buzzer Alert Logic
+Activates a buzzer if the air quality degrades beyond a certain threshold (800 PPM in this case).
+<code>
+#define BUZZER_PIN 25
+void setup() {
+  pinMode(BUZZER_PIN, OUTPUT);
+  digitalWrite(BUZZER_PIN, HIGH); // buzzer off
+}
+void loop() {
+  // ...
+  if (ppm > 800) {
+    digitalWrite(BUZZER_PIN, LOW); // buzzer on
+  } else {
+    digitalWrite(BUZZER_PIN, HIGH); // buzzer off
+  }
+}
+</code>
+  * Sending Data to Firebase
+Uploads the latest calculated PPM value to Firebase Realtime Database under the path /air_quality/ppm.
+<code>
+if (Firebase.RTDB.setFloat(&fbdo, "/air_quality/ppm", ppm)) {
+  Serial.println("Data sent to Firebase");
+} else {
+  Serial.print("Failed to send data: ");
+  Serial.println(fbdo.errorReason());
+}
+</code>
+}
+===== Web Application =====
+{{ :iothings:proiecte:2025sric:web_app_2.png?direct&300 |}}
+===== References =====
+  * [[https://www.instructables.com/Air-Quality-ESP32-Build-a-Portable-IoT-Sensor/]]
+  * [[https://www.hackster.io/dudelabweb/air-quality-monitoring-made-easy-an-iot-project-with-esp32-ee2777]]
+  * [[https://randomnerdtutorials.com/esp32-firebase-web-app/#install-vs-code]]
+  * [[https://randomnerdtutorials.com/getting-started-with-esp32/]]
+  * https://www.elprocus.com/mq135-air-quality-sensor/