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--- amc2021:code:start [2021/09/03 01:01] – [For Carbon Dioxide detection in air] kshama001
+++ amc2021:code:start [2021/09/03 18:48] (current) – removed kshama001
@@ Line 1: / Line 1: @@
-======Arduino Code======
-===== For Carbon Dioxide detection in air =====
-This code communicates with the MQ135 air quality sensor. The sensor is supposed to preheat for 24 hours before taking readings.
-Once the code runs, it prints out the concentration of detected gases in ppm on a serial monitor and the results are displayed on an LCD screen
-An alarm system (LED light) is also set to glow if the CO<sub>2<\sub> values cross a threshold value of 1000ppm.
-<code>
-#include "MQ135.h"
-#include <Wire.h>
-#include <LiquidCrystal_I2C.h>  //Header file for LCD
-LiquidCrystal_I2C lcd(0x27,16,2);//set the LCD address to x27 for a 16 chars and 2 line display
-#define led          9                       //led on pin 9
-const int gas_pin = A0;                      //analog feed from MQ135
-MQ135 gasSensor = MQ135(gas_pin);
-void setup(){
-  lcd.init();                      // initialize the lcd
-  lcd.begin(16,2);                  // consider 16 chars + 2 lines lcd
-  lcd.backlight();                 // illuminate to produce visible reading
-  lcd.clear();                     // clear lcd
-  lcd.setCursor(4,0);              //set cursor of lcd to 1st row and 5th column
-  lcd.print("Group L");          // print as a sentence on lcd
-  pinMode(gas_pin,INPUT);     //MQ135 analog feed set for input
-  pinMode(led,OUTPUT);        //led set for output
-  Serial.begin(9600);        //serial comms for debugging
-}
-void loop(){
- float ppm = gasSensor.getPPM();
- Serial.println(ppm);            // print ppm on serial monitor
- delay(1000);
-   lcd.clear();                  // clear lcd
-   lcd.setCursor(0,0);          // set cursor of lcd to 1st row and 1st column
-   lcd.print("Air Quality: ");  // print as a sentence on lcd
-   lcd.print(ppm);             // print value of MQ135
- if(ppm>999){                  //if co2 ppm > 1000
-    digitalWrite(led,HIGH);    //turn on led
-    lcd.setCursor(2,1);        // set cursor of lcd to 2nd row and 3rd column
-    lcd.print("AQ Level BAD");  //print as a sentence on lcd
-   }
- else{
-    digitalWrite(led,LOW);         //turn off led
-    lcd.setCursor(1,1);            // set cursor of lcd to 2nd row and 2nd column
-    lcd.print ("AQ Level Good");   // print as a sentence on lcd
-  }
-}
-</code>
-===== **For noise disturbance detection in the environment** =====
-<code>
-/* This code is meant to monitor the sound intensity using LM393 sensor connected to Arduino UNO board.
-//The used sensor has only a digital output. Therefore, the number of times the sensor detects a sound is summed up over a sampling time called "SAMPLE_TIME".
-//Then the sum called "sampleBufferValue" is printed on a Serial Monitor (laptop), and visualized with the Serial Plotter.
-// The code allows to communicate  with a LED in order to provide a visual alarm if the "sampleBufferValue" surpasses a preset Threshold  "Threshold" */
-// 0 means silence and 1 means noise
- const int OUT_PIN = 12;          // The OUTPUT of the sound sensor is connected to the digital pin D12 of the Arduino
- const int SAMPLE_TIME = 10;      // The sampling time in milliseconds,  can be set differently if required
- const int Threshold = 90;       // Threshold on decibel value for LED switching ON, the value has been optimized with respect to the used sampling time (900 cumulative digital counts ≈ 90 dB from "Schall")
- unsigned long millisCurrent;     // current time
- unsigned long millisLast = 0;    //previous time
- unsigned long millisElapsed = 0; // difference between current time and previous time (time interval)
- int sampleBufferValue = 0;       // initiate the sum of digital outputs over the sampling time
- int led = 8;                    // LED on pin 4 of Arduino
- int dB = 0;                     //initiate sound intensity dB value
-void setup() {
-  Serial.begin(9600);           //Arduino starts serial communication with baud rate 9600
-  pinMode(led,OUTPUT);          // the LED is connected as output for alarm purpose
-}
-void loop() {
-  millisCurrent = millis();                    //the current time is assigned to the dedicated variable
-  millisElapsed = millisCurrent - millisLast; //the elapsed time is updated
-  if(digitalRead(OUT_PIN) == HIGH){          //HIGH means noise
-  sampleBufferValue++;                       //increments the sum variable by 1
-  }
-   if (millisElapsed > SAMPLE_TIME) {       //if the elapsed time surpasses the sampling time, print the sampleBufferValue and test threshold for alarm
-   dB = 0.0666 *(sampleBufferValue) + 30.223; //linear regression to calculate the decibel value based of the rough calibration of the sensor response
-  Serial.println(dB);                        // print decibel values on the Serial Monitor
-  Serial.print("dB");                        // print sound unit decibel
-   if (sampleBufferValue > Threshold) {     // test if the threshold is surpassed
-    digitalWrite(led, HIGH);                //blink LED 2 ms ON and 1 ms OFF
-    delay(2);
-    digitalWrite(led, LOW);
-    delay(1);
-  }
-  digitalWrite(led, LOW);                  // the LED is turned off to be ready for the next sample
-  sampleBufferValue = 0;                   // re-initialization of the  sampleBufferValue variable for the new sampling time
-  millisLast = millisCurrent;              // update the previous time to be the start for the next sample
-  }
-}
-</code>