Diff: main.cpp

Revision:

0:cf9353d63f27

Child:

1:55620051895b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Sep 24 09:11:43 2015 +0000
@@ -0,0 +1,82 @@
+#include "mbed.h"
+#include "HIDScope.h"
+#include <cstring>
+#include <cmath>
+
+AnalogIn input1(A0); // first EMG input
+AnalogIn input2(A1); // second EMG input
+AnalogIn input3(A2); // third EMG input
+AnalogIn input4(A3); // fourth EMG input
+
+HIDScope    scope(2); // HIDScope declared
+
+// note that this filter is specified for a Fs of 512;
+// Butterworth low pass filter, second order at 2 hertz
+// Butterworth high pass filter, second order at 25 hertz
+int Fs = 512;
+const double low_b1 = 1.480219865318266e-04; //filter coefficients
+const double low_b2 = 2.960439730636533e-04;
+const double low_b3 = 1.480219865318266e-04;
+const double low_a2 = -1.965293372622690e+00; // a1 is normalized to 1
+const double low_a3 = 9.658854605688177e-01;
+const double high_b1 = 8.047897937631126e-01;
+const double high_b2 = -1.609579587526225e+00;
+const double high_b3 = 8.047897937631126e-01;
+const double high_a2 = -1.571102440190402e+00; // a1 is normalized to 1
+const double high_a3 = 6.480567348620491e-01;
+
+double inputs_current [4] = {}; // declaring an array for the inputs
+double inputs_previous [4] = {}; // previous input
+double inputs_previous2 [4] = {}; // second previous input
+
+double outputs_current [4] = {}; // same for outputs
+double outputs_previous [4] = {};
+double outputs_previous2 [4] = {};
+
+Ticker T1;
+
+// this function will be called by a ticker sample and filter
+volatile bool sample_go;
+
+void samplego()
+{
+    sample_go = 1;
+}
+
+
+void sample() // arrays are passed by reference, I think? 
+{
+    memmove(inputs_previous2, inputs_previous, sizeof(inputs_previous2)); // I hope this black magic works, equaling the array of previous2 to previous
+    memmove(inputs_previous, inputs_current, sizeof(inputs_previous)); // black magic again, this time previous to current
+    inputs_current[0] = input1;
+    inputs_current[1] = input2;
+    inputs_current[2] = input3;
+    inputs_current[3] = input4;
+}
+
+void filter() // filter: high --> full rect --> low 
+{
+    memmove(outputs_previous2, outputs_previous, sizeof(outputs_previous2)); // moving output one array back
+    memmove(outputs_previous, outputs_current, sizeof(outputs_previous)); // same for this output
+    for(int n = 0; n <= 3; n++)
+    {
+        outputs_current[n] = fabs(high_b1*inputs_current[n] + high_b2*inputs_previous[n] + high_b3*inputs_previous2[n] - high_a2*outputs_previous[n] - high_a3*outputs_previous2[n]) * (low_b1*inputs_current[n] + low_b2*inputs_previous[n] + low_b3*inputs_previous2[n] - low_a2*outputs_previous[n] - low_a3*outputs_previous2[n]);
+    }
+}
+
+int main()
+{
+    T1.attach(&samplego, (float)1/Fs);
+    while("pigs" != "fly")
+    {
+        if(sample_go)
+        {
+            sample();
+            filter();
+            scope.set(0,inputs_current[0]);
+            scope.set(1,outputs_current[0]);
+            sample_go = 0;
+            
+        } 
+    } 
+} // main end
\ No newline at end of file