ENVIROMENTAL.cpp

00001 #include "ENVIROMENTAL.h"
00002 
00003 
00004 //#define Ro 28 //Change this value with the value from Calibrate and uncomment
00005 
00006 
00007 ENVIROMENTAL::ENVIROMENTAL (PinName envi_SDA, PinName envi_SCL,PinName mq_analog):climate(envi_SDA,envi_SCL),bmp(envi_SDA,envi_SCL),i2c(envi_SDA,envi_SCL),uv(i2c)
00008 {
00009     _mq_pin = mq_analog;
00010     uv.begin(VEML6070_1_T);
00011 }
00012 ENVIROMENTAL::~ENVIROMENTAL(){}
00013 
00014 
00015 void ENVIROMENTAL::calibrate_mq()
00016 {
00017 
00018     AnalogIn analog_value(_mq_pin);
00019     float MQ7_read;
00020     float VRL;
00021     float Rs;
00022     float Ro;
00023     float RL;
00024       for(int test_cycle = 1 ; test_cycle <= 500 ; test_cycle++) //Read the analog output of the sensor for 200 times
00025               {
00026                 MQ7_read = MQ7_read + analog_value.read(); //add the values for 500
00027               }
00028       MQ7_read = MQ7_read/500.0f; //Take average
00029     VRL = MQ7_read*(5.0f); //Convert analog value to voltage
00030     Rs = ((5.0f/VRL)-1) * RL; //is the formula obtained from datasheet
00031     Ro = Rs/1.7f;  //RS/RO is 1.7 as we obtained from graph of datasheet
00032     printf("Ro at fresh air = %f\n\r",Ro);
00033 }
00034 
00035 
00036 
00037 float ENVIROMENTAL::get_CO()
00038 {
00039     AnalogIn analog_value(_mq_pin);
00040     float MQ7_read;
00041     float VRL;
00042     float Rs;
00043     float ratio;
00044     float Ro;
00045     float ppm;
00046     float RL;
00047     float m =-0.661;
00048     float b =1.332;
00049     for(int test_cycle = 1 ; test_cycle <= 500 ; test_cycle++) //Read the analog output of the sensor for 200 times
00050                 {
00051                   MQ7_read = MQ7_read + analog_value.read(); //add the values for 500
00052                 }
00053       MQ7_read = MQ7_read/500.0f; //Take average
00054 
00055     VRL = MQ7_read*(5.0f); //Convert analog value to voltage
00056     Rs = ((5.0f/VRL)-1.0f) * RL; //is the formula obtained from datasheet
00057     ratio = Rs/Ro;
00058     ppm = pow(10, ((log10(ratio)-b)/m)); //use formula to calculate ppm
00059     return ppm;
00060 }
00061 
00062 
00063 float ENVIROMENTAL::get_temp()
00064 {
00065   float temp=0;
00066   for(int i=0;i<20;i++)
00067     {
00068       _tmp = climate.get_temperature();
00069       temp=temp + _tmp;
00070   }
00071 
00072         return temp/20;
00073 
00074 }
00075 
00076 
00077 uint32_t ENVIROMENTAL::get_humidity(){
00078     _tmp=0;
00079     uint32_t hum=0;
00080     for(int i=0;i<20;i++)
00081       {
00082         _tmp=climate.get_humidity();
00083         hum = hum + _tmp;
00084     }
00085 
00086           return hum/20;
00087 
00088 }
00089 
00090 int32_t ENVIROMENTAL::get_pressure(){
00091     _tmp=0;
00092     int32_t pres=0;
00093     for(int i=0;i<20;i++)
00094       {
00095         _tmp=bmp.getPressure();
00096         pres = pres + _tmp;
00097     }
00098 
00099           return pres/20;
00100 
00101 }
00102 
00103 int ENVIROMENTAL::get_uv(){
00104     int uvi=0;
00105     _tmp=0;
00106     for(int i=0;i<20;i++)
00107       {
00108         _tmp = uv.readUV();
00109         uvi = uvi + _tmp;
00110     }
00111 
00112           return uvi/20;
00113     
00114     
00115     
00116 }