MQ-135 โมดูลตรวจจับแอมโมเนีย/เบนซิน MQ135 SNP-00055

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-135 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-135 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                     (1)     //define the load resistance on the board, in kilo ohms
12#define         RO_CLEAN_AIR_FACTOR          (3.59)  //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_CO2                      (0)
23#define         GAS_NH3                      (1)
24#define         GAS_ALCOHOL                  (2)
25
26/*****************************Globals***********************************************/
27float           CO2Curve[3]  =  {2.3, 0.72, -0.34};   // MQ-135 curve for CO2
28float           NH3Curve[3] = {2.3, 0.53, -0.44};     // MQ-135 curve for NH3
29float           AlcoholCurve[3] = {2.3, 0.67, -0.33}; // MQ-135 curve for Alcohol
30float           Ro                =  10;              //Ro is initialized to 10 kilo ohms
31
32void setup()
33{
34  Serial.begin(9600);                                //UART setup, baudrate = 9600bps
35  Serial.print("Calibrating...\n");
36  Ro = MQCalibration(MQ_PIN);                        //Calibrating the sensor. Please make sure the sensor is in clean air
37  Serial.print("Calibration is done...\n");
38  Serial.print("Ro=");
39  Serial.print(Ro);
40  Serial.print("kohm");
41  Serial.print("\n");
42}
43
44void loop()
45{
46  Serial.print("CO2:");
47  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_CO2) );
48  Serial.print( "ppm" );
49  Serial.print("    ");
50  Serial.print("NH3:");
51  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_NH3) );
52  Serial.print( "ppm" );
53  Serial.print("    ");
54  Serial.print("Alcohol:");
55  Serial.print(MQGetGasPercentage(MQRead(MQ_PIN) / Ro, GAS_ALCOHOL) );
56  Serial.print( "ppm" );
57  Serial.print("\n");
58  delay(200);
59}
60
61float MQResistanceCalculation(int raw_adc)
62{
63  return ( ((float)RL_VALUE * (1023 - raw_adc) / raw_adc));
64}
65
66float MQCalibration(int mq_pin)
67{
68  int i;
69  float val = 0;
70
71  for (i = 0; i < CALIBARAION_SAMPLE_TIMES; i++) {
72    val += MQResistanceCalculation(analogRead(mq_pin));
73    delay(CALIBRATION_SAMPLE_INTERVAL);
74  }
75  val = val / CALIBARAION_SAMPLE_TIMES;                 
76  val = val / RO_CLEAN_AIR_FACTOR;                      
77  return val;
78}
79
80float MQRead(int mq_pin)
81{
82  int i;
83  float rs = 0;
84
85  for (i = 0; i < READ_SAMPLE_TIMES; i++) {
86    rs += MQResistanceCalculation(analogRead(mq_pin));
87    delay(READ_SAMPLE_INTERVAL);
88  }
89
90  rs = rs / READ_SAMPLE_TIMES;
91  return rs;
92}
93
94int MQGetGasPercentage(float rs_ro_ratio, int gas_id)
95{
96  if ( gas_id == GAS_CO2 ) {
97    return MQGetPercentage(rs_ro_ratio, CO2Curve);
98  } else if ( gas_id == GAS_NH3 ) {
99    return MQGetPercentage(rs_ro_ratio, NH3Curve);
100  } else if ( gas_id == GAS_ALCOHOL ) {
101    return MQGetPercentage(rs_ro_ratio, AlcoholCurve);
102  }
103
104  return 0;
105}
106
107int MQGetPercentage(float rs_ro_ratio, float *pcurve)
108{
109  return (pow(10, ( ((log(rs_ro_ratio) - pcurve[1]) / pcurve[2]) + pcurve[0])));
110}
111