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Your first ESP32: install Arduino IDE and blink an LED

By EEDIY Team. Difficulty ★ · About 30-45 minutes Making an LED blink is the “hello world” of electronics. Once it works, you know your computer, cable, board and code are all working together.

What you need

  • 1 ESP32 development board (any common one)
  • 1 USB cable that carries data (some cables only charge)
  • 1 solderless breadboard
  • 1 LED and 1 resistor (from a starter kit’s LED section)
  • 2 jumper wires
  • A computer (Windows, macOS or Linux)
Words to know
  • GPIO: a general-purpose pin your code can switch on and off.
  • Sketch: an Arduino program.
  • Upload: sending the sketch from your computer to the board.

Step 1: Install the Arduino IDE

Download it from arduino.cc/en/software and install it like any other program.

Step 2: Add ESP32 support

  1. Open Preferences and paste Espressif’s board-manager URL into “Additional boards manager URLs”: https://espressif.github.io/arduino-esp32/package_esp32_index.json
  2. Open Boards Manager, search for esp32 and install the package by Espressif Systems.

Step 3: Wire the LED

An LED needs a series resistor to keep the current below the maximum forward current in the LED’s datasheet. For example, one common red LED datasheet lists 30 mA. Which resistor? 220–330 Ω is a typical choice. To work it out: R = (3.3 V − Vf) ÷ current, where Vf is the LED’s forward voltage from its datasheet. Example: the Kingbright WP7113ID has a typical Vf of 1.9 V at 10 mA, so (3.3 − 1.9) ÷ 0.010 = 140 Ω minimum. A 220 Ω resistor gives about 6 mA, which is still visible and safely below the limit.
  1. Connect a GPIO pin to one end of the resistor.
  2. Connect the other end of the resistor to the LED’s positive leg (anode).
  3. Connect the LED’s other leg (cathode) to a GND pin.
Not sure which leg is the anode? On the Kingbright WP7113ID drawing, the cathode (−) is the lead on the flat edge of the rim, and the anode (+) is the longer lead. Many 5 mm LEDs follow this, but check your LED’s datasheet. Check your board’s pinout to pick a normal GPIO pin, and write down its number. Avoid strapping pins (pins the chip reads at startup to decide how to boot): GPIO 0, 2, 5, 12 and 15 on the classic ESP32, and GPIO 4, 5, 8, 9 and 15 on the ESP32-C6. The example uses GPIO 18, which is not a strapping pin on either chip.

Step 4: Select your board and port

Plug in the board. In Tools, choose the board that matches the chip on yours: ESP32 Dev Module for a classic ESP32, ESP32C6 Dev Module for an ESP32-C6, or your exact model if it’s listed. Then choose the port that appeared.

Step 5: Upload the sketch

const int LED_PIN = 18;  // change to the GPIO you used
void setup() {
  pinMode(LED_PIN, OUTPUT);        // make the pin an output
}
void loop() {
  digitalWrite(LED_PIN, HIGH);     // LED on
  delay(500);                      // wait half a second
  digitalWrite(LED_PIN, LOW);      // LED off
  delay(500);
}
Click Upload.

Expected result

The upload reaches 100%, the board restarts, and the LED turns on for half a second, then off for half a second (one blink per second).

Common mistakes

Problem Fix
No port appears Tip: try a different USB cable (some cables only charge) or a different USB socket
Upload fails to connect Hold BOOT, press reset (or replug), release BOOT, then upload again
Uploads but LED stays dark The LED is in backwards (flip it; at 3.3 V that’s within the 5 V reverse-voltage rating in the example datasheet, so it’s usually not damaged), or the pin number in the code doesn’t match the wire
Wrong board selected Pick your exact board model in Tools

Next step

Change both delay(500) values to delay(100) and upload again. You just wrote your first change! Questions? The forum (ESP32 & MCUs) is coming soon.

Sources

Keep going

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