Add battery indicator

Battery.cpp

@@ -0,0 +1,107 @@
+#include <M5StickC.h>
+#include "Kernel.h"
+#include "Util.h"
+
+int voltage_to_percent(float voltage);
+void draw(int bars);
+
+#define BATTERY_OFFSET_X        141
+#define BATTERY_OFFSET_Y          1
+#define BATTERY_WIDTH            17
+#define BATTERY_HEIGHT            8
+#define BATTERY_BARS              4
+#define BATTERY_TERMINAL_HEIGHT   4
+#define BATTERY_TERMINAL_WIDTH    2
+#define BATTERY_COLOUR            0x999999
+#define BATTERY_LOW_COLOUR        0xAA0000
+#define BATTERY_PADDING           1
+#define BATTERY_BAR_COLOUR        0xAAAAAA
+
+int battery_bars = -1;
+
+int Battery(int pid, unsigned int signal)
+{
+  if (signal & SIGNAL_START)
+  {
+    Kernel_signal_mask(pid, SIGNAL_START | SIGNAL_STOP | SIGNAL_TICK | SIGNAL_REDRAW);
+  }
+  if (signal & SIGNAL_STOP)
+  {
+    return 255;
+  }
+  if (signal & SIGNAL_TICK)
+  {
+    float vbat = M5.Axp.GetVbatData() * 1.1 / 1000;
+    int percent = voltage_to_percent(vbat);
+    int bars = floor((percent / (100.0 / BATTERY_BARS)) + 0.5);
+    if (battery_bars != bars)
+    {
+      battery_bars = bars;
+      Kernel_signal(SIGNAL_REDRAW);
+    }
+  }
+
+  if (signal & SIGNAL_REDRAW)
+  {
+    draw(battery_bars);
+  }
+
+  return 0;
+}
+
+void draw(int bars)
+{
+  // Draw terminal
+  M5.Lcd.fillRect(
+     BATTERY_OFFSET_X,
+     BATTERY_OFFSET_Y + (BATTERY_HEIGHT / 2) - (BATTERY_TERMINAL_HEIGHT / 2),
+     BATTERY_TERMINAL_WIDTH,
+     BATTERY_TERMINAL_HEIGHT,
+     bars == 0 ? rgb_to_colour(BATTERY_LOW_COLOUR) : rgb_to_colour(BATTERY_COLOUR)
+     );
+  // Draw battery shell
+  M5.Lcd.drawRect(
+      BATTERY_OFFSET_X + BATTERY_TERMINAL_WIDTH,
+      BATTERY_OFFSET_Y,
+      BATTERY_WIDTH - BATTERY_TERMINAL_WIDTH,
+      BATTERY_HEIGHT,
+      bars == 0 ? rgb_to_colour(BATTERY_LOW_COLOUR) : rgb_to_colour(BATTERY_COLOUR)
+      );
+
+  // -2: for frame
+  int bar_width = (BATTERY_WIDTH - BATTERY_TERMINAL_WIDTH - 2 - (BATTERY_PADDING * (BATTERY_BARS + 1))) / BATTERY_BARS;
+  int bar_height = BATTERY_HEIGHT - (BATTERY_PADDING * 2) - 2;
+  int x = BATTERY_OFFSET_X + BATTERY_WIDTH - 1 - BATTERY_PADDING - bar_width;
+  int y = BATTERY_OFFSET_Y + 1 + BATTERY_PADDING;
+
+  while (bars > 0)
+  {
+    
+    M5.Lcd.fillRect(
+      x,
+      y,
+      bar_width,
+      bar_height,
+      rgb_to_colour(BATTERY_BAR_COLOUR)
+      );
+    x -= (bar_width + BATTERY_PADDING);
+    bars--;
+  }
+     
+  //M5.Lcd.setCursor(80, 20);
+  //M5.Lcd.print(bars);
+}
+
+int voltage_to_percent(float voltage)
+{
+  /*
+    4.2 volts 100%
+    4.1 about 90%
+    4.0 about 80%
+    3.9 about 60%
+    3.8 about 40%
+    3.7 about 20%
+    3.6 empty for practical purposes
+   */
+  return ((voltage - 3.6) / (4.2-3.6)) * 100;
+}

Battery.h

@@ -0,0 +1,2 @@
+
+int Battery(int pid, unsigned int signal);

watchos.ino

@@ -7,6 +7,7 @@
 #include "PowerManagement.h"
 #include "UserInput.h"
 #include "Clock.h"
+#include "Battery.h"
 
 int count = 0;
 bool input_a = false, input_b = false;
@@ -72,6 +73,8 @@ int test_func(int pid, unsigned int signal)
 void setup()
 {
   M5.begin();
+  Serial.begin(115200);
+  delay(30);
   Kernel_setup();
   int pid;
   pid = Kernel_start(&UI, 86400);
@@ -80,10 +83,12 @@ void setup()
   Serial.printf("[POWER] pid %d\n", pid);
   pid = Kernel_start(&UserInput, 0);
   Serial.printf("[INPUT] pid %d\n", pid);
-  pid = Kernel_start(&test_func, 5000);
-  Serial.printf("[TEST ] pid %d\n", pid);
+  //pid = Kernel_start(&test_func, 5000);
+  //Serial.printf("[TEST ] pid %d\n", pid);
   pid = Kernel_start(&Clock, 1000);
   Serial.printf("[CLOCK] pid %d\n", pid);
+  pid = Kernel_start(&Battery, 2000);
+  Serial.printf("[BATT ] pid %d\n", pid);
 
   M5.update();
   if (M5.BtnB.isPressed())