MQ-9 โมดูลตรวจจับคาร์บอนมอนอกไซด์/มีเทน MQ9 SNP-00054

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-2 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-9 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                     (10)    //define the load resistance on the board, in kilo ohms
12#define         RO_CLEAN_AIR_FACTOR          (9.8)   //RO_CLEAR_AIR_FACTOR=(Sensor resistance in clean air)/RO,
13//which is derived from the chart in datasheet
14
15/***********************Software Related Macros************************************/
16#define         CALIBARAION_SAMPLE_TIMES     (50)    //define how many samples you are going to take in the calibration phase
17#define         CALIBRATION_SAMPLE_INTERVAL  (500)   //define the time interval(in milliseconds) between each samples in the calibration phase
18#define         READ_SAMPLE_INTERVAL         (50)    //define the time interval(in milliseconds) between each samples in normal operation
19#define         READ_SAMPLE_TIMES            (5)     //define how many samples you are going to take in normal operation
20
21/**********************Application Related Macros**********************************/
22#define         GAS_CO                       (0)
23#define         GAS_COMBUSTIBLE              (1)
24
25/*****************************Globals***********************************************/
26float           COCurve[3]  =  {2.3, 0.72, -0.34};   // MQ-9 curve for CO
27float           CombustibleCurve[3] = {2.3, 0.53, -0.44}; // MQ-9 curve for combustible gases
28float           Ro                =  10;                 //Ro is initialized to 10 kilo ohms
29
30void setup()
31{
32  Serial.begin(9600);                                //UART setup, baudrate = 9600bps
33  Serial.print("Calibrating...\n");
34  Ro = MQCalibration(MQ_PIN);                        //Calibrating the sensor. Please make sure the sensor is in clean air
35  Serial.print("Calibration is done...\n");
36  Serial.print("Ro=");
37  Serial.print(Ro);
38  Serial.print("kohm");
39  Serial.print("\n");
40}
41
42void loop()
43{
44  Serial.print("CO:");
45  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_CO) );
46  Serial.print( "ppm" );
47  Serial.print("    ");
48  Serial.print("Combustible:");
49  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_COMBUSTIBLE) );
50  Serial.print( "ppm" );
51  Serial.print("\n");
52  delay(200);
53}
54
55float MQResistanceCalculation(int raw_adc)
56{
57  return ( ((float)RL_VALUE * (1023 - raw_adc) / raw_adc));
58}
59
60float MQCalibration(int mq_pin)
61{
62  int i;
63  float val = 0;
64
65  for (i = 0; i < CALIBARAION_SAMPLE_TIMES; i++) {
66    val += MQResistanceCalculation(analogRead(mq_pin));
67    delay(CALIBRATION_SAMPLE_INTERVAL);
68  }
69  val = val / CALIBARAION_SAMPLE_TIMES;                 
70  val = val / RO_CLEAN_AIR_FACTOR;                      
71  return val;
72}
73
74float MQRead(int mq_pin)
75{
76  int i;
77  float rs = 0;
78
79  for (i = 0; i < READ_SAMPLE_TIMES; i++) {
80    rs += MQResistanceCalculation(analogRead(mq_pin));
81    delay(READ_SAMPLE_INTERVAL);
82  }
83
84  rs = rs / READ_SAMPLE_TIMES;
85  return rs;
86}
87
88int MQGetGasPercentage(float rs_ro_ratio, int gas_id)
89{
90  if ( gas_id == GAS_CO ) {
91    return MQGetPercentage(rs_ro_ratio, COCurve);
92  } else if ( gas_id == GAS_COMBUSTIBLE ) {
93    return MQGetPercentage(rs_ro_ratio, CombustibleCurve);
94  }
95
96  return 0;
97}
98
99int MQGetPercentage(float rs_ro_ratio, float *pcurve)
100{
101  return (pow(10, ( ((log(rs_ro_ratio) - pcurve[1]) / pcurve[2]) + pcurve[0])));
102}
103