MQ-8 โมดูลตรวจจับไฮโดรเจน MQ8 SNP-00053

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-8 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          (9.21)  //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_HYDROGEN                 (0)
23
24/*****************************Globals***********************************************/
25float           HydrogenCurve[3]  =  {2.3, 0.93, -0.38};  // MQ-8 curve for H2
26float           Ro                =  10;                 //Ro is initialized to 10 kilo ohms
27
28void setup()
29{
30  Serial.begin(9600);                                //UART setup, baudrate = 9600bps
31  Serial.print("Calibrating...\n");
32  Ro = MQCalibration(MQ_PIN);                        //Calibrating the sensor. Please make sure the sensor is in clean air
33  Serial.print("Calibration is done...\n");
34  Serial.print("Ro=");
35  Serial.print(Ro);
36  Serial.print("kohm");
37  Serial.print("\n");
38}
39
40void loop()
41{
42  Serial.print("H2:");
43  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_HYDROGEN) );
44  Serial.print( "ppm" );
45  Serial.print("\n");
46  delay(200);
47}
48
49float MQResistanceCalculation(int raw_adc)
50{
51  return ( ((float)RL_VALUE * (1023 - raw_adc) / raw_adc));
52}
53
54float MQCalibration(int mq_pin)
55{
56  int i;
57  float val = 0;
58
59  for (i = 0; i < CALIBARAION_SAMPLE_TIMES; i++) {
60    val += MQResistanceCalculation(analogRead(mq_pin));
61    delay(CALIBRATION_SAMPLE_INTERVAL);
62  }
63  val = val / CALIBARAION_SAMPLE_TIMES;                 
64  val = val / RO_CLEAN_AIR_FACTOR;                      
65  return val;
66}
67
68float MQRead(int mq_pin)
69{
70  int i;
71  float rs = 0;
72
73  for (i = 0; i < READ_SAMPLE_TIMES; i++) {
74    rs += MQResistanceCalculation(analogRead(mq_pin));
75    delay(READ_SAMPLE_INTERVAL);
76  }
77
78  rs = rs / READ_SAMPLE_TIMES;
79  return rs;
80}
81
82int MQGetGasPercentage(float rs_ro_ratio, int gas_id)
83{
84  if ( gas_id == GAS_HYDROGEN ) {
85    return MQGetPercentage(rs_ro_ratio, HydrogenCurve);
86  }
87
88  return 0;
89}
90
91int MQGetPercentage(float rs_ro_ratio, float *pcurve)
92{
93  return (pow(10, ( ((log(rs_ro_ratio) - pcurve[1]) / pcurve[2]) + pcurve[0])));
94}
95