Autor: Burciu Iustin Florian Email: iustin.burciu@stud.fiir.upb.ro Grupa: AAC

This project focuses on building an embedded system to monitor environmental comfort using the ESP32 development board, along with an LM35 temperature sensor and an MQ-4 gas sensor. It continuously evaluates environmental conditions and computes a comfort score based on temperature and gas readings.

The implementation was initially created as a local web server hosted directly on the ESP32, allowing real-time monitoring from any browser within the same Wi-Fi network. Later, a second version was developed using Firebase Realtime Database, enabling remote data access and logging in real time from anywhere in the world.

The project includes:

• Real-time data acquisition from temperature and gas sensors
• Live display of sensor values and computed comfort score
• Visual charts and indicator LEDs (both virtual and physical)
• Automatic alerts and a persistent log for critical events
• Optional Firebase integration for remote access

Used Components:

• ESP32 DevKit V1 – WiFi + Bluetooth enabled development board
• LM35 – analog temperature sensor
• MQ-4 – analog gas sensor
• 2x LEDs (red and blue) – for visual alerts
• Jumper wires, breadboard

ESP32 Connections:

The designed system aims to monitor indoor environmental comfort by evaluating two essential parameters: temperature and gas concentration. These values are processed to calculate a comfort score ranging from 0 to 100, which reflects the overall air quality and thermal comfort.

The core functionalities of the system include:

• Reading analog values from the LM35 temperature sensor (in °C) and the MQ-4 gas sensor (in ppm).
• Computing the comfort score based on pre-defined thresholds for temperature and gas, penalizing deviations from optimal ranges.
• Real-time display of measurements through a web-based dashboard, hosted locally on the ESP32 microcontroller.
• Automatic dashboard refresh every 2 seconds, showing:
  • Current temperature
  • Gas level (methane/LPG)
  • Comfort score out of 100
  • Two animated line charts visualizing historical values
• Visual indicators (LEDs):
  • Red LED – lights up when gas level exceeds 30 ppm
  • Blue LED – lights up when the comfort score reaches 100
• Virtual LEDs on the web interface, mimicking the behavior of physical ones
• Persistent event log displaying timestamps, temperature, gas level, and comfort score whenever a threshold is crossed
• *(Optional)* Cloud integration with Firebase Realtime Database, using a separate sketch, allowing data to be viewed remotely

This system provides continuous assessment of the indoor environment, with a user-friendly interface that enables real-time monitoring and alerts, both locally and remotely via cloud services.

In a separate sketch, the system can also:

• Push live data to Firebase Realtime Database
• Use credentials and Web API key
• Display values remotely via a mobile app or web

1. Read Temperature and Gas:

```c float citesteTemperatura() {

int adc = analogRead(pinLM35);
float voltaj = adc * (5.0 / 4095.0);
return voltaj * 100.0;

}

int citesteGaz() {

return analogRead(pinMQ4);

}