First Light: Blinking an LED on the ESP32-S3

Bill of materials

The full build-log for this one lives at dankbuild.com. What follows here is the short summary: the parts, the wiring, and the blink sketch.

Why I started this

I build web things for a living, but lately I’ve been pulled toward hardware — microcontrollers, sensors, and the satisfying moment when code makes something in the physical world move. The build-logs are my notebook: what I built, the bill of materials, the wiring, the code, and the gotchas.

The classic “hello world”: blink

Every embedded journey starts with blinking an LED. Here it is on an ESP32-S3 using the Arduino core:

#define LED_PIN 2

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

void loop() {
  digitalWrite(LED_PIN, HIGH);
  delay(500);
  digitalWrite(LED_PIN, LOW);
  delay(500);
}

Wire the LED to GPIO2 through a 220Ω resistor to ground, flash, and you’ve got first light.

The mistakes are written up on the canonical copy rather than here: see Flashing it, and what goes wrong the first time.

The hardware build-logs have their own home at dankbuild.com — that copy of this post is the canonical one, and new ESP32 write-ups land there, not here. There’s no newsletter and nothing to sign up for: they show up in the RSS 2.0 feed at dankbuild.com/feed.xml, which you can paste into any feed reader.

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