MQ-5 โมดูลตรวจจับ LGP/มีเทน/แก๊สธรรมชาติ/ไฮโดรเจน MQ5 SNP-00050

1int sensor = 7;
2int val = 0;
3void setup() {
4  Serial.begin(9600);
5}
6void loop() {
7  val = digitalRead(sensor);
8  if (val == 0) {
9    Serial.println("MQ-5 Detected");
10  }
11  delay(500);
12}

1int sensor = A0;
2int val = 0;
3void setup() {
4  Serial.begin(9600);
5}
6void loop() {
7  val = analogRead(sensor);
8  Serial.println(val);
9  delay(500);
10}

1/*******************Demo for MQ-5 Gas Sensor Module*****************************
2  Support:  Tiequan Shao: support[at]sandboxelectronics.com
3  Lisence: Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)
4  Note:    This piece of source code is supposed to be used as a demonstration ONLY.
5           More sophisticated calibration is required for industrial field application.
6                                                    Sandbox Electronics    2011-04-25
7************************************************************************************/
8
9/************************Hardware Related Macros************************************/
10#define         MQ_PIN                       (0)     //define which analog input channel you are going to use
11#define         RL_VALUE                     (5)     //define the load resistance on the board, in kilo ohms
12#define         RO_CLEAN_AIR_FACTOR          (6.5)   //RO_CLEAR_AIR_FACTOR=(Sensor resistance in clean air)/RO, for MQ-5
13
14/***********************Software Related Macros************************************/
15#define         CALIBARAION_SAMPLE_TIMES     (50)    //define how many samples you are going to take in the calibration phase
16#define         CALIBRATION_SAMPLE_INTERVAL  (500)   //define the time interal(in milisecond) between each samples in the calibration phase
17#define         READ_SAMPLE_INTERVAL         (50)    //define the time interval(in milisecond) between each samples in normal operation
18#define         READ_SAMPLE_TIMES            (5)     //define how many samples you are going to take in normal operation
19
20/**********************Application Related Macros**********************************/
21#define         GAS_LPG                      (0)
22#define         GAS_CO                       (1)
23#define         GAS_H2                       (2)
24
25/*****************************Globals***********************************************/
26float           LPGCurve[3]  =  {2.3, 0.21, -0.47};  // MQ-5 curve for LPG
27float           COCurve[3]   =  {2.3, 0.72, -0.34};  // MQ-5 curve for CO
28float           H2Curve[3]   =  {2.3, 0.26, -0.36};  // MQ-5 curve for Hydrogen (H2)
29float           Ro           =  10;                  //Ro is initialized to 10 kilo ohms
30
31void setup()
32{
33  Serial.begin(9600);                                //UART setup, baudrate = 9600bps
34  Serial.print("Calibrating...\n");
35  Ro = MQCalibration(MQ_PIN);                        //Calibrating the sensor. Please make sure the sensor is in clean air
36  Serial.print("Calibration is done...\n");
37  Serial.print("Ro=");
38  Serial.print(Ro);
39  Serial.print("kohm");
40  Serial.print("\n");
41}
42
43void loop()
44{
45  Serial.print("LPG:");
46  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_LPG) );
47  Serial.print( "ppm" );
48  Serial.print("    ");
49  Serial.print("CO:");
50  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_CO) );
51  Serial.print( "ppm" );
52  Serial.print("    ");
53  Serial.print("H2:");
54  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_H2) );
55  Serial.print( "ppm" );
56  Serial.print("\n");
57  delay(200);
58}
59
60float MQResistanceCalculation(int raw_adc)
61{
62  return ( ((float)RL_VALUE * (1023 - raw_adc) / raw_adc));
63}
64
65float MQCalibration(int mq_pin)
66{
67  int i;
68  float val = 0;
69
70  for (i = 0; i < CALIBARAION_SAMPLE_TIMES; i++) {
71    val += MQResistanceCalculation(analogRead(mq_pin));
72    delay(CALIBRATION_SAMPLE_INTERVAL);
73  }
74  val = val / CALIBARAION_SAMPLE_TIMES;                 
75  val = val / RO_CLEAN_AIR_FACTOR;                      
76  return val;
77}
78
79float MQRead(int mq_pin)
80{
81  int i;
82  float rs = 0;
83
84  for (i = 0; i < READ_SAMPLE_TIMES; i++) {
85    rs += MQResistanceCalculation(analogRead(mq_pin));
86    delay(READ_SAMPLE_INTERVAL);
87  }
88
89  rs = rs / READ_SAMPLE_TIMES;
90  return rs;
91}
92
93int MQGetGasPercentage(float rs_ro_ratio, int gas_id)
94{
95  if ( gas_id == GAS_LPG ) {
96    return MQGetPercentage(rs_ro_ratio, LPGCurve);
97  } else if ( gas_id == GAS_CO ) {
98    return MQGetPercentage(rs_ro_ratio, COCurve);
99  } else if ( gas_id == GAS_H2 ) {
100    return MQGetPercentage(rs_ro_ratio, H2Curve);
101  }
102
103  return 0;
104}
105
106int MQGetPercentage(float rs_ro_ratio, float *pcurve)
107{
108  return (pow(10, ( ((log(rs_ro_ratio) - pcurve[1]) / pcurve[2]) + pcurve[0])));
109}
110