Set up your ESP32 and blink an LED

1. Install Arduino IDE and ESP32 support

Open Arduino IDE 2 on the Windows computer. In File → Preferences, add https://espressif.github.io/arduino-esp32/package_esp32_index.json to Additional Boards Manager URLs. Open Boards Manager, search for esp32, and install “esp32 by Espressif Systems”.

2. Select your board and port

Connect the classroom ESP32-WROOM board with a USB data cable. Select ESP32 Dev Module. Choose its COM port under Tools → Port. To identify the port, compare the list with the board unplugged and plugged in; the newly appearing port belongs to your board.

3. Prove the connection with Serial Monitor

Upload this sketch, open Serial Monitor and set it to 115200 baud. You should see “My ESP32 works!” repeat.

void setup() {
  Serial.begin(115200);
}

void loop() {
  Serial.println("My ESP32 works!");
  delay(1000);
}

4. Wire the external LED

Use the ESP32, breadboard, LED, a 220Ω or 330Ω resistor, and jumper wires. Connect GPIO 23 → resistor → the LED’s long positive leg. Connect the short negative leg → GND. The resistor is in series with the LED.

5. Upload the blink program

Upload the sketch below. The LED should stay on for one second, off for one second, and repeat. LED names GPIO 23; pinMode makes it an output; digitalWrite sets its level; delay pauses for a number of milliseconds.

const int LED = 23;

void setup() {
  pinMode(LED, OUTPUT);
}

void loop() {
  digitalWrite(LED, HIGH);
  delay(1000);
  digitalWrite(LED, LOW);
  delay(1000);
}

6. Change the pattern

Try making the blink five times faster. Then try two quick flashes followed by a longer pause, an SOS pattern of short and long flashes, and your own repeating signal. Ask a partner to describe your pattern before seeing the code.

7. Troubleshoot one thing at a time

If no port appears, check the USB connection and data cable. If upload fails, check the selected board and port and ask for help with the BOOT button. If the code uploads but the LED does not light, check its direction, GPIO number, GND connection and breadboard rows. Change one thing at a time.

8. Explain the system

Describe how code makes the microcontroller produce an electrical signal and a physical output. An ESP32 controlling an LED is an embedded system; the connected-service part of the IoT project comes later.