Diff: measurement/Potentiometer.cpp

Revision:

113:3872569be2af

Parent:

101:dbcd3bc51758

Child:

114:80610be056e2

--- a/measurement/Potentiometer.cpp	Fri May 15 10:14:05 2015 +0000
+++ b/measurement/Potentiometer.cpp	Fri May 15 14:07:51 2015 +0000
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include "rtos.h"
 #include "Potentiometer.h"
 #include "SmartRestConf.h"
 #include "logging.h"
@@ -14,7 +15,24 @@
 size_t Potentiometer::read(char *buf, size_t maxLen, char *status, size_t num)
 {
         static const char *fmt = "107,%ld,%f,%f\r\n";
-        float data[2] = {(float)analog1*100, (float)analog2*100};
+        const unsigned short N = 10;
+        float data[2] = {0, 0};
+        float min[2] = {100, 100};
+        float max[2] = {0, 0};
+        // multiple sampling for data smoothing
+        for (unsigned short i = 0; i < N; ++i) {
+            float d0 = (float)analog1*100;
+            float d1 = (float)analog2*100;
+            data[0] += d0;
+            data[1] += d1;
+            min[0] = min[0] <= d0 ? min[0] : d0;
+            min[1] = min[1] <= d1 ? min[1] : d1;
+            max[0] = max[0] >= d0 ? max[0] : d0;
+            max[1] = max[1] >= d1 ? max[1] : d1;
+            Thread::wait(10);
+        }
+        data[0] = (data[0]-min[0]-max[0]) / (N-2);
+        data[1] = (data[1]-min[1]-max[1]) / (N-2);
 
         if (abs(oldValues[0]-data[0]) <= abs(oldValues[0])*THRESHOLD_PERCENT_ANA &&
             abs(oldValues[1]-data[1]) <= abs(oldValues[1])*THRESHOLD_PERCENT_ANA) {