Merge pull request #168 from Panky-codes/fix-erratic-battery

Fix erratic battery

src/components/battery/BatteryController.cpp

@@ -34,9 +34,11 @@ void Battery::Update() {
 
   // see https://forum.pine64.org/showthread.php?tid=8147
   voltage = (value * 2.0f) / (1024/3.0f);
-  percentRemaining = ((voltage - 3.55f)*100.0f)*3.9f;
-  percentRemaining = std::max(percentRemaining, 0.0f);
-  percentRemaining = std::min(percentRemaining, 100.0f);
+  int percentRemaining = ((voltage - 3.55f)*100.0f)*3.9f;
+  percentRemaining = std::max(percentRemaining, 0);
+  percentRemaining = std::min(percentRemaining, 100);
+
+  percentRemainingBuffer.insert(percentRemaining);
 
 //  NRF_LOG_INFO("BATTERY " NRF_LOG_FLOAT_MARKER " %% - " NRF_LOG_FLOAT_MARKER " v", NRF_LOG_FLOAT(percentRemaining), NRF_LOG_FLOAT(voltage));
 //  NRF_LOG_INFO("POWER Charging : %d - Power : %d", isCharging, isPowerPresent);

src/components/battery/BatteryController.h

@@ -1,14 +1,48 @@
 #pragma once
 #include <cstdint>
 #include <drivers/include/nrfx_saadc.h>
+#include <array>
+#include <numeric>
 
 namespace Pinetime {
   namespace Controllers {
+  /** A simple circular buffer that can be used to average 
+   out the sensor values. The total capacity of the CircBuffer  
+   is given as the template parameter N.
+   */ 
+  template <int N> 
+  class CircBuffer {
+  public:
+    CircBuffer() : arr{}, sz{}, cap{N}, head{} {}
+    /**
+   insert member function overwrites the next data to the current 
+   HEAD and moves the HEAD to the newly inserted value.
+   */ 
+    void insert(const int num) {
+      head %= cap;
+      arr[head++] = num;
+      if (sz != cap) {
+        sz++;
+      }
+    }
+
+    int GetAverage() const {
+      int sum = std::accumulate(arr.begin(), arr.end(), 0);
+      return (sum / sz);
+    }
+
+  private:
+    std::array<int, N> arr; /**< internal array used to store the values*/
+    uint8_t sz; /**< The current size of the array.*/
+    uint8_t cap; /**< Total capacity of the CircBuffer.*/
+    uint8_t head; /**< The current head of the CircBuffer*/
+  };
+
     class Battery {
       public:
         void Init();
         void Update();
-        float PercentRemaining() const { return percentRemaining; }
+        int PercentRemaining() const { return percentRemainingBuffer.GetAverage(); }
         float Voltage() const { return voltage; }
         bool IsCharging() const { return isCharging; }
         bool IsPowerPresent() const { return isPowerPresent; }
@@ -17,8 +51,9 @@ namespace Pinetime {
         static constexpr uint32_t chargingPin = 12;
         static constexpr uint32_t powerPresentPin = 19;
         static constexpr nrf_saadc_input_t batteryVoltageAdcInput = NRF_SAADC_INPUT_AIN7;
+        static constexpr uint8_t percentRemainingSamples = 10;
         static void SaadcEventHandler(nrfx_saadc_evt_t const * p_event);
-        float percentRemaining = 0.0f;
+        CircBuffer<percentRemainingSamples> percentRemainingBuffer {};
         float voltage = 0.0f;
         bool isCharging = false;
         bool isPowerPresent = false;

src/displayapp/screens/BatteryIcon.cpp

@@ -3,11 +3,11 @@
 
 using namespace Pinetime::Applications::Screens;
 
-const char* BatteryIcon::GetBatteryIcon(float batteryPercent) {
-  if(batteryPercent > 90.0f) return Symbols::batteryFull;
-  if(batteryPercent > 75.0f) return Symbols::batteryThreeQuarter;
-  if(batteryPercent > 50.0f) return Symbols::batteryHalf;
-  if(batteryPercent > 25.0f) return Symbols::batteryOneQuarter;
+const char* BatteryIcon::GetBatteryIcon(int batteryPercent) {
+  if(batteryPercent > 90) return Symbols::batteryFull;
+  if(batteryPercent > 75) return Symbols::batteryThreeQuarter;
+  if(batteryPercent > 50) return Symbols::batteryHalf;
+  if(batteryPercent > 25) return Symbols::batteryOneQuarter;
   return Symbols::batteryEmpty;
 }
 

src/displayapp/screens/BatteryIcon.h

@@ -6,7 +6,7 @@ namespace Pinetime {
       class BatteryIcon {
       public:
         static const char* GetUnknownIcon();
-          static const char* GetBatteryIcon(float batteryPercent);
+          static const char* GetBatteryIcon(int batteryPercent);
           static const char* GetPlugIcon(bool isCharging);
       };
     }

src/displayapp/screens/Clock.h

@@ -64,7 +64,7 @@ namespace Pinetime {
           Pinetime::Controllers::DateTime::Days currentDayOfWeek = Pinetime::Controllers::DateTime::Days::Unknown;
           uint8_t currentDay = 0;
 
-          DirtyValue<float> batteryPercentRemaining  {0};
+          DirtyValue<int> batteryPercentRemaining  {0};
           DirtyValue<bool> bleState {false};
           DirtyValue<std::chrono::time_point<std::chrono::system_clock, std::chrono::nanoseconds>> currentDateTime;
           DirtyValue<uint32_t> stepCount  {0};