1 · First steps
Blink an LED
Beginner10 min
Goal
Turn an LED on pin 13 on and off every second.
Why it matters
This is the “Hello World” of electronics: it proves the board, the code and the wiring all work.
What you need
- Arduino UNO board
- 5 mm LED
- 220 Ω resistor
Nothing to buy: every component below is simulated in the browser.
Steps
- 01Drop an Arduino UNO, a 220 Ω resistor and an LED on the canvas.
- 02Set the LED pin to 13 and wire it through the resistor.
- 03Call pinMode(13, OUTPUT) inside setup().
- 04Alternate digitalWrite(13, HIGH/LOW) with delay(1000) inside loop().
This tutorial runs inside the Circuitly simulator: your wiring and your code are checked automatically at every step.
Frequently asked questions
- Do I need to buy hardware for this tutorial?
- No. Everything runs in the browser: Circuitly simulates the board, the components and the code. Real hardware is optional if you want to rebuild the circuit afterwards.
- Which components are used?
- Arduino UNO board, 5 mm LED, 220 Ω resistor. They are already available in the simulator library.
- How long does it take?
- About 10 minutes, beginner level, in 4 guided steps.
- What should I know before starting?
- Nothing: this is a starting point of the series. No software install is required.
- Is the code provided and checked?
- The simulator checks your wiring and your code automatically at every step, and shows the commented solution if you get stuck.
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In the same series
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