HT16K33 7-Segment Backpack

// HT16K33 7-Segment Backpack on Arduino Uno: wiring and a free simulation at https://www.tinkered.ai/components/ht16k33-7segment
// Adafruit 0.56" HT16K33 7-segment backpack on an Arduino Uno: D -> A4, C -> A5, address 0x70
// Counts seconds as MM:SS with a blinking colon.
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_LEDBackpack.h>

Adafruit_7segment display;

void setup() {
  Serial.begin(115200);
  if (!display.begin(0x70)) {
    Serial.println(F("HT16K33 not found at 0x70"));
    while (true) {}
  }
  display.setBrightness(8); // 0 to 15
  Serial.println(F("Display ready"));
}

void loop() {
  unsigned long seconds = millis() / 1000;
  int minutes = (seconds / 60) % 100;
  int secs = seconds % 60;
  display.writeDigitNum(0, minutes / 10); // positions 0, 1, 3, 4 are digits; 2 is the colon
  display.writeDigitNum(1, minutes % 10);
  display.writeDigitNum(3, secs / 10);
  display.writeDigitNum(4, secs % 10);
  display.drawColon(seconds % 2 == 0);
  display.writeDisplay();
  static unsigned long last = 0;
  if (seconds != last) {
    last = seconds;
    Serial.print(F("Elapsed: "));
    Serial.print(minutes);
    Serial.print(':');
    if (secs < 10) Serial.print('0');
    Serial.println(secs);
  }
  delay(100);
}

// HT16K33 7-Segment Backpack on ESP32 DevKit V1: wiring and a free simulation at https://www.tinkered.ai/components/ht16k33-7segment
// Adafruit 0.56" HT16K33 7-segment backpack on an ESP32 DevKit V1: D -> GPIO21, C -> GPIO22, address 0x70
// Counts seconds as MM:SS with a blinking colon.
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_LEDBackpack.h>

Adafruit_7segment display;

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22); // SDA, SCL
  if (!display.begin(0x70, &Wire)) {
    Serial.println("HT16K33 not found at 0x70");
    while (true) { delay(100); }
  }
  display.setBrightness(15); // full brightness helps at 3.3 V
  Serial.println("Display ready");
}

void loop() {
  unsigned long seconds = millis() / 1000;
  int minutes = (seconds / 60) % 100;
  int secs = seconds % 60;
  display.writeDigitNum(0, minutes / 10);
  display.writeDigitNum(1, minutes % 10);
  display.writeDigitNum(3, secs / 10);
  display.writeDigitNum(4, secs % 10);
  display.drawColon(seconds % 2 == 0);
  display.writeDisplay();
  static unsigned long last = 0;
  if (seconds != last) {
    last = seconds;
    Serial.printf("Elapsed: %d:%02d\n", minutes, secs);
  }
  delay(100);
}

// HT16K33 7-Segment Backpack on Raspberry Pi Pico: wiring and a free simulation at https://www.tinkered.ai/components/ht16k33-7segment
// Adafruit 0.56" HT16K33 7-segment backpack on a Raspberry Pi Pico (arduino-pico): D -> GP4, C -> GP5, address 0x70
// Counts seconds as MM:SS with a blinking colon.
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_LEDBackpack.h>

Adafruit_7segment display;

void setup() {
  Serial.begin(115200);
  Wire.setSDA(4);
  Wire.setSCL(5);
  if (!display.begin(0x70, &Wire)) {
    Serial.println("HT16K33 not found at 0x70");
    while (true) { delay(100); }
  }
  display.setBrightness(15);
  Serial.println("Display ready");
}

void loop() {
  unsigned long seconds = millis() / 1000;
  int minutes = (seconds / 60) % 100;
  int secs = seconds % 60;
  display.writeDigitNum(0, minutes / 10);
  display.writeDigitNum(1, minutes % 10);
  display.writeDigitNum(3, secs / 10);
  display.writeDigitNum(4, secs % 10);
  display.drawColon(seconds % 2 == 0);
  display.writeDisplay();
  static unsigned long last = 0;
  if (seconds != last) {
    last = seconds;
    Serial.print("Elapsed: ");
    Serial.print(minutes);
    Serial.print(':');
    if (secs < 10) Serial.print('0');
    Serial.println(secs);
  }
  delay(100);
}