ESP32 OLED 0.96 18650 holder battery- SKU: M101

// For a connection via I2C using the Arduino Wire include:
#include <Wire.h>               // Only needed for Arduino 1.6.5 and earlier
#include "SSD1306Wire.h"        // legacy: #include "SSD1306.h"

// I2C OLED Display works with SSD1306 driver
#define OLED_SDA 5
#define OLED_SCL 4
#define LED      16
//#define OLED_RST 16

// Initialize the OLED display using Arduino Wire:
SSD1306Wire display(0x3C, OLED_SDA, OLED_SCL);   // ADDRESS, SDA, SCL  -  SDA and SCL usually populate automatically based on your board's pins_arduino.h e.g. https://github.com/esp8266/Arduino/blob/master/variants/nodemcu/pins_arduino.h


#define DEMO_DURATION 3000
typedef void (*Demo)(void);

int demoMode = 0;
int counter = 1;

void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.println();
  pinMode(LED, OUTPUT);
  blinky();


  // Initialising the UI will init the display too.
  display.init();

  display.flipScreenVertically();
  display.setFont(ArialMT_Plain_10);

}

void blinky() {
  for (int i = 0; i < 5; i++) {
    digitalWrite(16, HIGH);   // turn the LED on (HIGH is the voltage level)
    delay(300);                       // wait for a second
    digitalWrite(16, LOW);    // turn the LED off by making the voltage LOW
    delay(500);
  }
}

void drawFontFaceDemo() {
  // Font Demo1
  // create more fonts at http://oleddisplay.squix.ch/
  display.setTextAlignment(TEXT_ALIGN_LEFT);
  display.setFont(ArialMT_Plain_24);
  display.drawString(0, 0, "HwThinker");
  display.setFont(ArialMT_Plain_16);
  display.drawString(0, 26, "in Action");
  display.setFont(ArialMT_Plain_10);
  display.drawString(0, 45, "Nature");
}

void drawTextFlowDemo() {
  display.setFont(ArialMT_Plain_10);
  display.setTextAlignment(TEXT_ALIGN_LEFT);
  display.drawStringMaxWidth(0, 0, 128,
                             "Lorem ipsum\n dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore." );
}

void drawTextAlignmentDemo() {
  // Text alignment demo
  display.setFont(ArialMT_Plain_10);

  // The coordinates define the left starting point of the text
  display.setTextAlignment(TEXT_ALIGN_LEFT);
  display.drawString(0, 10, "Left aligned (0,10)");

  // The coordinates define the center of the text
  display.setTextAlignment(TEXT_ALIGN_CENTER);
  display.drawString(64, 22, "Center aligned (64,22)");

  // The coordinates define the right end of the text
  display.setTextAlignment(TEXT_ALIGN_RIGHT);
  display.drawString(128, 33, "Right aligned (128,33)");
}

void drawRectDemo() {
  // Draw a pixel at given position
  for (int i = 0; i < 10; i++) {
    display.setPixel(i, i);
    display.setPixel(10 - i, i);
  }
  display.drawRect(12, 12, 20, 20);

  // Fill the rectangle
  display.fillRect(14, 14, 17, 17);

  // Draw a line horizontally
  display.drawHorizontalLine(0, 40, 20);

  // Draw a line horizontally
  display.drawVerticalLine(40, 0, 20);
}

void drawCircleDemo() {
  for (int i = 1; i < 8; i++) {
    display.setColor(WHITE);
    display.drawCircle(32, 32, i * 3);
    if (i % 2 == 0) {
      display.setColor(BLACK);
    }
    display.fillCircle(96, 32, 32 - i * 3);
  }
}

void drawProgressBarDemo() {
  int progress = (counter / 5) % 100;
  // draw the progress bar
  display.drawProgressBar(0, 32, 120, 10, progress);

  // draw the percentage as String
  display.setTextAlignment(TEXT_ALIGN_CENTER);
  display.drawString(64, 15, String(progress) + "%");
}


Demo demos[] = {drawFontFaceDemo, drawTextFlowDemo, drawTextAlignmentDemo, drawRectDemo, drawCircleDemo, drawProgressBarDemo};
int demoLength = (sizeof(demos) / sizeof(Demo));
long timeSinceLastModeSwitch = 0;

void loop() {
  // clear the display
  display.clear();
  // draw the current demo method
  demos[demoMode]();

  display.setFont(ArialMT_Plain_10);
  display.setTextAlignment(TEXT_ALIGN_RIGHT);
  display.drawString(128, 54, String(millis()));
  // write the buffer to the display
  display.display();

  if (millis() - timeSinceLastModeSwitch > DEMO_DURATION) {
    demoMode = (demoMode + 1)  % demoLength;
    timeSinceLastModeSwitch = millis();
  }
  counter++;
  delay(10);
}