MQ-3 โมดูลตรวจจับแอลกอฮอล์ MQ3 SNP-00048

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-3 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-3 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. More
5         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          (60.0)  //RO_CLEAR_AIR_FACTOR for MQ-3, this value may vary. Please refer to the MQ-3 datasheet
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 interval (in milliseconds) between each sample in the calibration phase
17#define         READ_SAMPLE_INTERVAL         (50)    //define the time interval (in milliseconds) between each sample 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_ALCOHOL                  (0)
22
23/*****************************Globals***********************************************/
24float           AlcoholCurve[3]  =  {2.3, 0.94, -0.45};  //two points are taken from the curve for MQ-3 alcohol detection
25//data format:{ x, y, slope}; these values are approximated based on the datasheet
26
27float           Ro           =  10;                 //Ro is initialized to 10 kilo ohms
28
29void setup()
30{
31  Serial.begin(9600);                               //UART setup, baudrate = 9600bps
32  Serial.print("Calibrating...\n");
33  Ro = MQCalibration(MQ_PIN);                       //Calibrating the sensor. Please make sure the sensor is in clean air when you perform the calibration
34  Serial.print("Calibration is done...\n");
35  Serial.print("Ro=");
36  Serial.print(Ro);
37  Serial.print("kohm");
38  Serial.print("\n");
39}
40
41void loop()
42{
43  Serial.print("ALCOHOL:");
44  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_ALCOHOL) );
45  Serial.print( "ppm" );
46  Serial.print("\n");
47  delay(200);
48}
49
50/****************** MQResistanceCalculation ****************************************/
51float MQResistanceCalculation(int raw_adc)
52{
53  return ( ((float)RL_VALUE * (1023 - raw_adc) / raw_adc));
54}
55
56/***************************** MQCalibration ****************************************/
57float MQCalibration(int mq_pin)
58{
59  int i;
60  float val = 0;
61
62  for (i = 0; i < CALIBARAION_SAMPLE_TIMES; i++) {      //take multiple samples
63    val += MQResistanceCalculation(analogRead(mq_pin));
64    delay(CALIBRATION_SAMPLE_INTERVAL);
65  }
66  val = val / CALIBARAION_SAMPLE_TIMES;                 //calculate the average value
67
68  val = val / RO_CLEAN_AIR_FACTOR;                      //divided by RO_CLEAN_AIR_FACTOR yields the Ro
69
70  return val;
71}
72
73/*****************************  MQRead *********************************************/
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
86  return rs;
87}
88
89/*****************************  MQGetGasPercentage **********************************/
90int MQGetGasPercentage(float rs_ro_ratio, int gas_id)
91{
92  if ( gas_id == GAS_ALCOHOL ) {
93    return MQGetPercentage(rs_ro_ratio, AlcoholCurve);
94  }
95
96  return 0;
97}
98
99/*****************************  MQGetPercentage **********************************/
100int  MQGetPercentage(float rs_ro_ratio, float *pcurve)
101{
102  return (pow(10, ( ((log(rs_ro_ratio) - pcurve[1]) / pcurve[2]) + pcurve[0])));
103}
104