Measuring the Speed of Sound in Gases as a Means of Identifying Them

1// SoundSpeed_3D_2022
2// IDE 1.8.19
3// Adapted and modified by Alberto Villalobos (IDE 1.8.19)
4//
5// Basic Bluetooth sketch HC-06_01
6// Connect the HC-06 module and communicate using the serial monitor
7// The HC-06 defaults to AT mode when first powered on.
8// The default baud rate is 9600
9// The HC-06 requires all AT commands to be in uppercase. NL+CR should not be added to the command string
10//
11// Ultrasonic Sensor HC-SR04 and Arduino Tutorial
12// Crated by Dejan Nedelkovski,
13// www.HowToMechatronics.com
14//https://randomnerdtutorials.com
15
16#include <SoftwareSerial.h>
17#include <OneWire.h>
18#include <DallasTemperature.h>
19
20SoftwareSerial BTserial(2, 3); // RX | TX
21// Connect the HC-06 TX to the Arduino RX on pin 2. 
22// Connect the HC-06 RX to the Arduino TX on pin 3 through a voltage divider.
23
24// Data wire is conntec to the Arduino digital pin 4
25#define ONE_WIRE_BUS 4
26
27// Setup a oneWire instance to communicate with any OneWire devices
28OneWire oneWire(ONE_WIRE_BUS);
29
30// Pass our oneWire reference to Dallas Temperature sensor 
31DallasTemperature sensors(&oneWire);
32
33double Temperatura;
34double CorrecTemp = -3.3; //Correction to the temperature initially measured by the sensor
35float duration;
36
37// defines pins numbers
38
39const int trigPin = 9;
40const int echoPin = 10;
41
42void setup() {
43  
44pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
45pinMode(echoPin, INPUT); // Sets the echoPin as an Input
46
47Serial.begin(9600);    
48BTserial.begin(9600); // HC-06 default serial speed is 9600
49
50// Start up the library
51  sensors.begin();
52}
53 
54void loop()
55{ 
56// Call sensors.requestTemperatures() to issue a global temperature and Requests to all devices on the bus
57  sensors.requestTemperatures(); 
58  
59  Temperatura = sensors.getTempCByIndex(0) + CorrecTemp;  
60 
61 // Clears the trigPin
62 
63digitalWrite(trigPin, LOW);
64delayMicroseconds(2);
65
66// Sets the trigPin on HIGH state for 10 micro seconds
67
68digitalWrite(trigPin, HIGH);
69delayMicroseconds(10);
70digitalWrite(trigPin, LOW);
71
72// Reads the echoPin, returns the sound wave travel time in microseconds
73
74duration = pulseIn(echoPin, HIGH);
75
76// Print measurements to bluetooth serial monitor
77
78BTserial.print("<");
79BTserial.print(duration);BTserial.print(" ");
80BTserial.print(Temperatura);BTserial.print(" ");
81BTserial.println(">");
82
83delay(150); // This speed must be less than or equal to the bluetooth clock speed in App Inventor 2
84
85}