Diff: Alphasense.cpp

Revision:

0:ed1f58bf0dc3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Alphasense.cpp	Wed Mar 06 14:01:39 2019 +0000
@@ -0,0 +1,35 @@
+#include "Alphasense.h"
+#include "Adafruit_ADS1015.h"
+
+ALPHASENSE::ALPHASENSE(I2C* i2c, int num_chan_op1, int num_chan_op2, int we0, int ae0, int sensitivity, int n_sample) : _i2c(i2c), _num_chan_op1(num_chan_op1), _num_chan_op2(num_chan_op2), _we0(we0), _ae0(ae0), _sensitivity(sensitivity), _n_sample(n_sample) {   
+}
+
+float ALPHASENSE::measure() {
+    double we_result, ae_result;
+    float result;
+    int we, ae, we_integral, ae_integral;
+    
+    Adafruit_ADS1115 ads(_i2c); //init ads1115
+    ads.setGain(GAIN_TWO); //set range to 2.048 V
+    
+    for (int i=0; i<_n_sample; i++)
+    {
+        we = ads.readADC_SingleEnded(_num_chan_op1); // read channel
+        ae = ads.readADC_SingleEnded(_num_chan_op2);
+        we_integral += we;
+        ae_integral += ae;
+    }
+
+    we_result = we_integral / _n_sample; //smoothing result
+    ae_result = ae_integral / _n_sample;
+    
+    we_result = we_result * 0.0625; //conversion to mV (2048 / 65536)
+    ae_result = ae_result * 0.0625;
+    
+    we_integral = 0; //reset integral
+    ae_integral = 0;
+    
+    result = (((we_result - _we0) - (ae_result - _ae0)) / _sensitivity) * 1000; //conversion to ppb
+
+    return result;
+}
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