countdown running (not resettable)

src/Color.cpp

@@ -0,0 +1,17 @@
+#include "Color.h"
+
+#define ___     0
+#define TTT     85
+#define HHH     127
+#define XXX     255
+
+// @formatter:off
+Color RED       (XXX, ___, ___);
+Color YELLOW    (HHH, HHH, ___);
+Color GREEN     (___, XXX, ___);
+Color TURQUOISE (___, HHH, HHH);
+Color BLUE      (___, ___, XXX);
+Color MAGENTA   (HHH, ___, HHH);
+Color WHITE     (TTT, TTT, TTT);
+Color BLACK     (___, ___, ___);
+// @formatter:on

src/Color.h

@@ -0,0 +1,31 @@
+#ifndef WS2812B_COLOR_H
+#define WS2812B_COLOR_H
+
+#include <Arduino.h>
+
+struct Color {
+  uint8_t r, g, b;
+
+  Color(uint8_t r, uint8_t g, uint8_t b) : r(r), g(g), b(b) {
+    //
+  }
+
+};
+
+extern Color RED;
+
+extern Color YELLOW;
+
+extern Color GREEN;
+
+extern Color TURQUOISE;
+
+extern Color BLUE;
+
+extern Color MAGENTA;
+
+extern Color WHITE;
+
+extern Color BLACK;
+
+#endif

src/display.cpp

@@ -0,0 +1,85 @@
+#include "display.h"
+
+#define SEGMENTS_PER_DIGIT  7
+#define LEDS_PER_SEGMENT    6
+#define LEDS_PER_DOT        2
+#define DOT_COUNT           4
+#define DOTS_AFTER_DIGIT    1
+
+uint8_t CHARS[] = {
+    0b11111100, // 0
+    0b00110000, // 1
+    0b01101110, // 2
+    0b01111010, // 3
+    0b10110010, // 4
+    0b11011010, // 5, S
+    0b11011110, // 6
+    0b01110000, // 7
+    0b11111110, // 8
+    0b11111010, // 9
+    0b11100110, // P
+    0b11110110, // A
+    0b10111100, // U
+};
+
+int toIndex(char c) {
+  if (c >= '0' && c <= '9') {
+    return c - '0';
+  }
+  switch (c) {
+    case 'P':
+      return 10;
+  }
+  return -1;
+}
+
+uint8_t mapChar(char c) {
+  const int index = toIndex(c);
+  if (index >= 0) {
+    return CHARS[index];
+  }
+  return 0;
+}
+
+void drawChar(Adafruit_NeoPixel& pixels, int digit, char c, bool showIfZero, Color& color) {
+  if (c == '0' && !showIfZero) {
+    return;
+  }
+  auto pixel = digit * SEGMENTS_PER_DIGIT * LEDS_PER_SEGMENT + (digit > DOTS_AFTER_DIGIT ? DOT_COUNT * LEDS_PER_DOT : 0);
+  const auto symbol = mapChar(c);
+  Serial.printf("  character '%c'\n", c);
+  uint8_t symbolMask = 128;
+  for (int segment = 0; segment < SEGMENTS_PER_DIGIT; ++segment) {
+    const auto on = (symbol & symbolMask) != 0;
+    Serial.printf("    segment %d = %s\n", segment, on ? "ON" : "__");
+    if (on) {
+      for (int led = 0; led < LEDS_PER_SEGMENT; ++led) {
+        pixels.setPixelColor(pixel, color.r, color.g, color.b);
+        pixel++;
+      }
+    } else {
+      pixel += LEDS_PER_SEGMENT;
+    }
+    symbolMask >>= 1;
+  }
+}
+
+void drawNumber(Adafruit_NeoPixel& pixels, int digit, int number, bool zero, Color& color) {
+  const char ten = '0' + (number / 10 % 10);
+  const char one = '0' + (number % 10);
+  drawChar(pixels, digit + 0, ten, zero, color);
+  drawChar(pixels, digit + 1, one, true, color);
+}
+
+void drawDot(Adafruit_NeoPixel& pixels, int dot, const Color& c) {
+  int index = 2 * SEGMENTS_PER_DIGIT * LEDS_PER_SEGMENT + dot * LEDS_PER_DOT;
+  pixels.setPixelColor(index++, c.r, c.g, c.b);
+  pixels.setPixelColor(index++, c.r, c.g, c.b);
+}
+
+void drawDots(Adafruit_NeoPixel& pixels, Color& bottom, Color& middleBottom, Color& middleTop, Color& top) {
+  drawDot(pixels, 0, bottom);
+  drawDot(pixels, 1, middleBottom);
+  drawDot(pixels, 2, middleTop);
+  drawDot(pixels, 3, top);
+}

src/display.h

@@ -0,0 +1,14 @@
+#ifndef WS2812B_DISPLAY_H
+#define WS2812B_DISPLAY_H
+
+#include <Adafruit_NeoPixel.h>
+
+#include "Color.h"
+
+void drawChar(Adafruit_NeoPixel& pixels, int digit, char c, bool showIfZero, Color& color);
+
+void drawNumber(Adafruit_NeoPixel& pixels, int digit, int number, bool zero, Color& color);
+
+void drawDots(Adafruit_NeoPixel& pixels, Color& bottom, Color& middleBottom, Color& middleTop, Color& top);
+
+#endif

src/main.cpp

@@ -1,11 +1,4 @@
-#include <Adafruit_NeoPixel.h>
-
-#define countof(a)  (sizeof(a) / sizeof((a)[0]))
-
-#define ___         0
-#define TTT         85
-#define HHH         127
-#define XXX         255
+#include "display.h"
 
 #define GPIO        26
 #define PIXELS      (4 * 7 * 6 + 4 * 4)
@@ -13,26 +6,6 @@
 
 Adafruit_NeoPixel pixels(PIXELS, GPIO, NEO_GRB + NEO_KHZ800);
 
-struct color {
-  uint8_t r, g, b;
-};
-
-color colors[] = {
-    {XXX, ___, ___},
-    {HHH, HHH, ___},
-    {___, XXX, ___},
-    {___, HHH, HHH},
-    {___, ___, XXX},
-    {HHH, ___, HHH},
-    {TTT, TTT, TTT},
-};
-
-color *c = colors;
-
-int step = 0;
-
-int dir = 1;
-
 void setup() {
   delay(500);
   Serial.begin(115200);
@@ -40,15 +13,48 @@ void setup() {
   pixels.begin();
   pixels.setBrightness(BRIGHTNESS);
   pixels.clear();
+  pixels.show();
+}
+
+long configCountdownSeconds = 65;
+
+long countdownRestMillis = configCountdownSeconds * 1000;
+
+unsigned long last = 0;
+
+void updateTime() {
+  const auto now = max(1UL, millis());
+  if (last != 0) {
+    const auto diff = now - last;
+    countdownRestMillis -= (long) diff;
+    if (countdownRestMillis < 0) {
+      countdownRestMillis = 0;
+    }
+  }
+  last = now;
+}
+
+void showTime() {
+  const auto secondsTotal = (unsigned long) ceil(countdownRestMillis / 1000.0);
+  const auto minutes = (int) secondsTotal / 60;
+  const auto seconds = (int) secondsTotal % 60;
+
+  static auto lastSeconds = -1;
+  if (lastSeconds == seconds) {
+    return;
+  }
+  lastSeconds = seconds;
+
+  Serial.printf("%2d:%02d\n", minutes, seconds);
+
+  pixels.clear();
+  drawNumber(pixels, 0, minutes, false, WHITE);
+  drawDots(pixels, BLACK, WHITE, WHITE, BLACK);
+  drawNumber(pixels, 2, seconds, true, WHITE);
+  pixels.show();
 }
 
 void loop() {
-  pixels.setPixelColor(step, c->r, c->g, c->b);
-  pixels.show();
-
-  step += dir;
-  if (step < 0 || step > PIXELS - 1) {
-    dir = -dir;
-    c = (c + 1 - colors) % countof(colors) + colors;
-  }
+  updateTime();
+  showTime();
 }