Revision 9:487acc0ebf8f, committed 2015-07-02

Comitter:

bridadan

Date:

Thu Jul 02 01:43:07 2015 +0000

Parent:

8:e7c198206c5f

Commit message:

Added parameter for number of good readings before triggering change event. Updating docs.

Changed in this revision

--- a/ColorDetector.cpp	Thu Jul 02 01:07:28 2015 +0000
+++ b/ColorDetector.cpp	Thu Jul 02 01:43:07 2015 +0000
@@ -2,9 +2,9 @@
 #include "math.h"
 
 
-ColorDetector::ColorDetector(GroveColourSensor *sensor, uint16_t threshold, uint16_t varianceThreshold, uint16_t diffThreshold, uint16_t samplesPerReading)
-    :sensor(sensor), threshold(threshold), varianceThreshold(varianceThreshold), diffThreshold(diffThreshold), changeDetected(false), curBuffPointer(0),
-    samplesPerReading(samplesPerReading) {
+ColorDetector::ColorDetector(GroveColourSensor *sensor, uint16_t threshold, uint16_t varianceThreshold, uint16_t diffThreshold, uint16_t samplesPerReading, uint16_t readingsPerEvent)
+    :sensor(sensor), threshold(threshold), varianceThreshold(varianceThreshold), diffThreshold(diffThreshold), samplesPerReading(samplesPerReading), readingsPerEvent(readingsPerEvent),
+    changeDetected(false), curBuffPointer(0) {
         // Empty
 }
 
@@ -111,11 +111,11 @@
             totalDiff += diff;
         }
         
-        for (int i = 0; i < DIFF_BUFF_LEN - 1; i++) {
+        for (int i = 0; i < readingsPerEvent - 1; i++) {
             diffBuff[i] = diffBuff[i + 1];
         }
         
-        diffBuff[DIFF_BUFF_LEN - 1] = totalDiff;
+        diffBuff[readingsPerEvent - 1] = totalDiff;
         
         printf("totalDiff: %d\r\n", totalDiff);
         if (totalDiff > threshold) {
@@ -136,8 +136,8 @@
 
 int32_t ColorDetector::getTotalPastDiff() {
     int32_t totalDiff = 0;
-    for (int i = 0; i < DIFF_BUFF_LEN - 1; i++) {
-        totalDiff += abs(diffBuff[DIFF_BUFF_LEN - 1] - diffBuff[i]);
+    for (int i = 0; i < readingsPerEvent - 1; i++) {
+        totalDiff += abs(diffBuff[readingsPerEvent - 1] - diffBuff[i]);
     }
     return totalDiff;
 }

--- a/ColorDetector.h	Thu Jul 02 01:07:28 2015 +0000
+++ b/ColorDetector.h	Thu Jul 02 01:43:07 2015 +0000
@@ -5,7 +5,7 @@
 #include "GroveColourSensor.h"
 
 #define CD_BUFF_LEN 512
-#define DIFF_BUFF_LEN 6
+#define DIFF_BUFF_LEN 4
 
 
 /** ColorDetector class.
@@ -17,13 +17,14 @@
      *    Constructor.
      *
      *    @param sensor Pointer to instantiated and powered up Grove colour sensor.
-     *    @param threshold Total change in channel values needed to trigger a "change" event. (default 15)
-     *        This will start to save samples for later use until the total change in channel values dips below this threshold or the sample buffer is filled.
+     *    @param threshold Total change in channel values needed to be considered a "differnet" reading from the baseline. (default 15)
      *    @param varianceThreshold The maximum difference in variance between samples that is allowed for a "steady" reading. (default 3)
-     *    @param diffThreshold The maximum difference between past readings that is allowed for a "steady" reading. (default 2)
+     *    @param diffThreshold The maximum difference between past readings that is allowed for a "consistent" reading. (default 2)
      *    @param samplesPerReading Specifies the number of samples to take per sample() call. (default 256)
+     *    @param readingsPerEvent Number of readings that must be "steady", "consistent", and "different" before triggering a "change detected" event. (default 4)
+     *        NOTE: Must be less than or equal to DIFF_BUFF_LEN (default 4).
      */
-    ColorDetector(GroveColourSensor *sensor, uint16_t threshold = 15, uint16_t varianceThreshold = 3, uint16_t diffThreshold = 2, uint16_t samplesPerReading = 256);
+    ColorDetector(GroveColourSensor *sensor, uint16_t threshold = 15, uint16_t varianceThreshold = 3, uint16_t diffThreshold = 2, uint16_t samplesPerReading = 256, uint16_t readingsPerEvent = 4);
     
     /**
      *    This establishes the average "resting" channel values. This should be called before calling sample().
@@ -31,7 +32,11 @@
     void setBaseline();
     
     /**
-     *    Takes samples from sensor. It trackes whether the change in color rises above the threshold given in the constructor.
+     *    Takes a new reading from the sensor. First, it checks to see if the variance between the samples in the reading is
+     *    less than the varianceThreshold. If it is, the reading is considered "steady" and a candidate "change detected" event.
+     *    Next, it checks to see if the total average difference between the last samples is greater
+     
+     It trackes whether the change in color rises above the threshold given in the constructor.
      *    If the total change in color rises above and then falls bellow this threshold, or if the sample buffer is filled,
      *    this will return a value greater than 0 that indicates how many samples are in the buffer. Otherwise, it returns 0.
      */
@@ -54,6 +59,7 @@
     bool changeDetected;
     uint16_t samplesPerReading;
     int32_t diffBuff[DIFF_BUFF_LEN];
+    uint16_t readingsPerEvent;
     
     /**
      *    Takes the specified number of samples and returns the average color channel values.