Build an OLED Sensor Dashboard

Understand the target result

Design a readable OLED layout for labels, values, units, and status indicators. The expected result is: The display refreshes values without unreadable overlap or flicker.

Prepare the board and parts

Disconnect the ESP32 from USB. Put the ESP32, breadboard, jumper wires, and the listed lesson parts in front of you. Straighten bent pins gently and never force a module into the breadboard.

Make each connection with power off

1. OLED VCC → ESP32 3.3V.
2. OLED GND → ESP32 GND.
3. OLED SDA → GPIO 21.
4. OLED SCL → GPIO 22.

Install any library and upload the code

Install “Adafruit SSD1306” and “Adafruit GFX” from Arduino Library Manager. Select your ESP32 board and serial port before clicking Upload.

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
Adafruit_SSD1306 display(128, 64, &Wire, -1);
void setup() { Wire.begin(21, 22); display.begin(SSD1306_SWITCHCAPVCC, 0x3C); display.setTextColor(SSD1306_WHITE); }
void loop() {
  int sensorValue = analogRead(34);
  display.clearDisplay(); display.setTextSize(1); display.setCursor(0, 0); display.println("YKR038 SENSOR");
  display.setTextSize(2); display.setCursor(0, 24); display.print(sensorValue);
  display.setTextSize(1); display.setCursor(0, 52); display.println("ADC reading"); display.display();
  delay(250);
}

Power the circuit and observe

Connect USB power only after the wiring check. Open Serial Monitor at 115200 baud when the sketch prints data. Watch the circuit for at least 20 seconds and compare it with this expected behavior: The display refreshes values without unreadable overlap or flicker.

Change one value and test again

Make one small change—such as a delay, threshold, brightness, or displayed message—then upload again. This confirms that you understand which part of the program controls the result.