ESP32 OLED WiFi Display — ESP32 simulation

ESP32 with SSD1306 OLED showing WiFi connection status and IP address

An interactive ESP32 circuit simulation you can run free in your browser on Velxio, by ericcraft-mail.

Components

• Ssd1306

Sketch code

#include <Wire.h>
#include <WiFi.h>
#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

// Define SPI pins based on the wiring above
#define OLED_MOSI   23
#define OLED_CLK    18
#define OLED_DC      2
#define OLED_CS      5
#define OLED_RESET   4

// Declaration for SSD1306 display connected using software SPI
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);

const char* ssid = "RUT_F2CE_2G"; //RUT_F2CE_2G Espressif
const char* pwd  = "n9E5WjMf"; // n9E5WjMf

//display.drawBitmap(112, 0, cell_no_signal_16x8, 16, 8, SSD1306_WHITE);
// const unsigned char cell_no_signal_16x8[] = {
//   0x00, 0x00, 0x04, 0x10, 0x02, 0x20, 0x01, 0x40, 0x00, 0x80, 0x01, 0x40, 0x02, 0x20, 0x04, 0x10
// };

// Draw 4-bar signal strength icon at (x, y), each bar 3px wide, 2px gap
// Bars grow upward: bar0 is shortest (left), bar3 is tallest (right)
void drawSignalIcon(int x, int y, int8_t rssi) {
  const int barWidth  = 2;
  const int gap       = 1;
  const int maxHeight = 10;
  const int minBar    = 1; // minimum bar height so even bar0 is visible

  // Map RSSI (-90..-30) to signal level (0..4 bars)
  int level;
  if (rssi >= -40)      level = 5; // excellent
  else if (rssi >= -50) level = 4; // good
  else if (rssi >= -60) level = 3; // good
  else if (rssi >= -70) level = 2; // fair
  else if (rssi >= -80) level = 1; // weak
  else                  level = 0; // no signal

  for (int i = 0; i < 5; i++) {
    // Bar heights: 2, 4, 6, 8 pixels
    int barH = minBar + (maxHeight - minBar) * (i + 1) / 5;
    // x position for this bar (left to right, shortest to tallest)
    int bx = x + i * (barWidth + gap);

    // Draw bar outline (full height)
    //display.drawRect(bx, y + maxHeight - barH, barWidth, barH, SSD1306_WHITE);

    // Fill only if this bar is within the active level
    if (i < level) {
      display.fillRect(bx, y + maxHeight - barH, barWidth, barH, SSD1306_WHITE);
    }
  }
}

// Draw times icon procedural starting at x and y position, size of image drawn (size = 8x8)
void drawTimesIcon(int8_t x, int8_t y, int8_t size){
  // Get the last y coords to draw backward
  int yH = y + size - 1; // 16 + 8 - 1 = 23

  for (int i = 0; i < size; i++) {
    display.drawPixel(x + i, y + i, SSD1306_WHITE);
    display.drawPixel(x + i, yH - i, SSD1306_WHITE);
  }
}

void setup() {
  Serial.begin(115200);
  //Wire.begin(21, 22);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("SSD1306 not found!");
    while (true) delay(10);
  }

  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 20);
  display.printf("Connecting to SSID:\n%s", ssid);

  WiFi.begin(ssid, pwd);  // channel 6, no password

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
    display.print(".");
    display.display();
  }

  Serial.println("Connected!");
}

void loop() {
  display.cl

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