Add Library and Code

Library-and-Code.md

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+# Library and Code 
+The prototype firmware was developed using the Arduino IDE together with the ESP32 board support
+package and the corresponding sensor libraries. Each sensor requires a specific library to simplify hardware
+configuration, communication, and data acquisition. The following sections summarize the main software
+components and execution flow for each supported sensor.
+
+## GP2Y1010AU0F Dust Sensor 
+### Required Libraries and Object Definitions
+The GP2Y1010AU0F does not require a dedicated Arduino library because it provides an analog output.
+The firmware uses the standard Arduino library: 
+```
+#include <Arduino.h>
+```
+The sensor is accessed directly through an ADC-capable GPIO and a GPIO used to control the internal
+infrared LED.
+### Important Pin Definitions
+The firmware defines:
+* One ADC pin connected to the sensor output.
+* One digital output pin connected to the LED control input.
+These pins are initialized during the setup phase before measurements begin.
+
+### Data Processing
+The ADC reading is converted into sensor voltage and then into an estimated dust concentration using the
+calibration equation implemented in the firmware. The calculated value may be displayed on the Serial
+Monitor or transmitted to another system.
+ 
+## LMV324-Based Sound Detector
+### Required Libraries and Object Definitions
+The Sound Detector also provides an analog output and therefore does not require a dedicated Arduino
+library. 
+```
+#include <Arduino.h>
+```
+### Important Pin Definitions 
+The firmware defines an ADC input connected to the module Envelope output.
+### Data Acquisition 
+Sound intensity is measured using 
+```
+analogRead()
+```
+which samples the analog voltage generated by the Sound Detector.
+### Data Processing
+The measured ADC value is converted into voltage and used as an indication of the detected sound level.
+Since the module is not factory calibrated in dB SPL, the measured voltage represents relative sound
+intensity.
+## Sensirion SCD30 Sensor
+### Required Libraries and Object Definitions
+The SCD30 requires the following Arduino libraries:
+```
+#include <Wire.h>
+#include <SensirionI2cScd30.h>
+```
+The sensor object is created as:
+```
+SensirionI2cScd30 scd30_sensor;
+```
+### Important Pin Definitions
+The I²C interface is configured using:
+```
+#define I2C_SDA_PIN 20
+#define I2C_SCL_PIN 21
+```
+These GPIOs provide the SDA and SCL communication lines between the ESP32 and the SCD30.
+
+### Data Acquisition
+The firmware first verifies that new data is available using:
+```
+scd30_sensor.getDataReady()
+```
+When data is ready, the measurements are retrieved using: 
+```
+scd30_sensor.readMeasurementData()
+```
+### Data Processing
+The library returns calibrated values directly in engineering units:
+* CO₂ (ppm)
+* Temperature (°C)
+* Relative Humidity (%RH)
+No additional ADC conversion or mathematical processing is required before the values are displayed or
+transmitted.
+