Irregularly sampled exponentially weighted average for current displays.

(merging branch june-2.4.1-amm-ewa)

Squashed commit of the following:

commit af23c49
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Mon Jul 3 23:15:46 2017 -0700

    binaries recompiled, unit test flag switched off.

commit a51ee9d
Merge: ebe9994 923284d
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Mon Jul 3 23:09:48 2017 -0700

    Merge branch 'june-2.4.1' into june-2.4.1-amm-ewa

commit ebe9994
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Sun Jul 2 22:45:39 2017 -0700

    regenerating binaries after merge

commit bcaefd2
Merge: e941499 4f7d133
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Sun Jul 2 22:45:16 2017 -0700

    Merge branch 'june-2.4.1' into june-2.4.1-amm-ewa

commit e941499
Merge: 4281b96 7b34d3f
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Sun Jul 2 19:23:42 2017 -0700

    Merge branch 'june-2.4.1' into june-2.4.1-amm-ewa

commit 4281b96
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Sun Jul 2 09:01:46 2017 -0700

    more comments, binary.

commit cfc1fa2
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Sat Jul 1 17:22:20 2017 -0700

    Bug fixes; recompiled binary; probably ok to try with the smoother.

Hydra_EVSE/Hydra_EVSE.h

@@ -32,6 +32,7 @@
 #include <Time.h>
 #include <DS1307RTC.h>
 //#include <Timezone.h>
+#include "onlineSum.h"
 #include "dst.h"
 
 // SW version
@@ -253,6 +254,13 @@
 // doe RB = 27 - Mega Hydra production
 //#define CURRENT_SCALE_FACTOR 184
 
+// Irregular-sampled EWA half-period for ammeter displays (the time after which data points a weighed 1/2
+// w.r.t. most recent data point). This is for Ammeter display only, it does not affect current measurements
+// for overdraw etc. purposes.
+#define AMM_DISPLAY_HALF_PERIOD 1500
+
+
+
 #define LOG_NONE 0
 #define LOG_INFO 1
 #define LOG_DEBUG 2
@@ -346,7 +354,7 @@ struct car_struct {
   unsigned long last_current_log;
   boolean seq_done = false;
   unsigned int pilot_state;
-//  unsigned long current_samples[ROLLING_AVERAGE_SIZE];
+  EWASumD ammSum;
 
   car_struct(unsigned int car, int themOffset, unsigned int relay_pin, 
   unsigned int pilot_out_pin, unsigned int pilot_sense_pin, unsigned int current_pin) :
@@ -362,9 +370,9 @@ struct car_struct {
     request_time(0),
     error_time(0),
     last_current_log(0),
-    pilot_state(LOW)
+    pilot_state(LOW),
+    ammSum(AMM_DISPLAY_HALF_PERIOD)
   {
-//    memset(current_samples, 0, sizeof(current_samples));
   };
 
   void setRelay(unsigned int state);
@@ -494,6 +502,7 @@ extern persisted_struct persisted;
 extern void Delay(unsigned int);
 extern void displayStatus(unsigned int status);
 extern char errLetter(unsigned int status);
+extern char *formatMilliamps(unsigned long milliamps);
 
 extern boolean &enable_dst;
 extern car_struct cars[];

Hydra_EVSE/Hydra_EVSE.ino

@@ -617,13 +617,13 @@ int car_struct::checkState()
 
 static inline unsigned long ulong_sqrt(unsigned long in)
 {
-  unsigned long out;
-  // find the last int whose square is not too big
-  // Yes, it's wasteful, but we only theoretically ever have to go to 512.
-  // Removing floating point saves us almost 1K of flash.
-  for (out = 1; out * out <= in; out++) ;
-  return out - 1;
-  //  return (unsigned long)sqrt((float)in);
+  //  unsigned long out;
+  //  // find the last int whose square is not too big
+  //  // Yes, it's wasteful, but we only theoretically ever have to go to 512.
+  //  // Removing floating point saves us almost 1K of flash.
+  //  for (out = 1; out * out <= in; out++) ;
+  //  return out - 1;
+  return sqrt((double)in);
 }
 
 unsigned long car_struct::readCurrent()
@@ -1953,16 +1953,21 @@ void car_struct::loopCurrentMonitor() {
       // car A is under its limit. Cancel any overdraw in progress
       overdraw_begin = 0;
     }
+
+    // update the ammeter display.
+    ammSum.update(car_draw, millis());
+
     display.setCursor(dispCol(), 1);
     display.print(carLetter());
     display.print(':');
-    display.print(formatMilliamps(car_draw));
+    display.print(formatMilliamps(ammSum.ewa()));
   }
   else
   {
     // Car A is not charging
     overdraw_begin = 0;
-//    memset(current_samples, 0, sizeof(current_samples));
+    ammSum.reset();
+    //    memset(current_samples, 0, sizeof(current_samples));
   }
 
 }