Diff: MQ2.h

Revision:

0:a5033edf6975

Child:

1:323f72b59e99

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MQ2.h	Thu Oct 05 11:33:31 2017 +0000
@@ -0,0 +1,52 @@
+#ifndef MQ2_h
+#define MQ2_h
+
+#include "mbed.h"
+
+#define RL_VALUE                    5                                           //define the load resistance on the board, in kilo ohms
+#define RO_DEFAULT                  10 
+#define RO_CLEAN_AIR_FACTOR         9.83f 
+#define CALIBARAION_SAMPLE_TIMES    5
+#define CALIBRATION_SAMPLE_INTERVAL 50
+#define READ_SAMPLE_INTERVAL        50
+#define READ_SAMPLE_TIMES           5
+
+//The curves
+static float LPGCurve[]   = {2.3f,0.21f,-0.47f};
+static float COCurve[]    = {2.3f,0.72f,-0.34f};
+static float SmokeCurve[] = {2.3f,0.53f,-0.44f};
+
+typedef struct {
+  float lpg;
+  float co;
+  float smoke;
+} MQ2_data_t;
+
+typedef enum  {
+    GAS_LPG = 0,
+    GAS_CO = 1,
+    GAS_SMOKE = 2
+} GasType;
+
+
+class MQ2 {
+public: 
+    MQ2(PinName pin) : _pin(pin){
+      Ro = RO_DEFAULT;
+    };
+    void read(MQ2_data_t *ptr);
+    float readLPG();
+    float readCO();
+    float readSmoke();
+    void begin();
+private:
+    AnalogIn _pin;
+    float MQRead();
+    float MQGetGasPercentage(float rs_ro_ratio, GasType gas_id);
+    int MQGetPercentage(float rs_ro_ratio, float *pcurve);
+    float MQCalibration();
+    float MQResistanceCalculation(int raw_adc);
+    float Ro;
+};
+
+#endif
\ No newline at end of file