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, Push button. They are already available in the simulator library.

How long does it take?

About 30 minutes, expert level, in 4 guided steps.

What should I know before starting?

The previous tutorial in the series, “Remember after power-off (EEPROM)”, is enough preparation. 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.

All tutorials

5 · Communication & data

State machine

Expert30 min

Goal

Structure a traffic light into explicit states (GREEN, AMBER, RED).

Why it matters

A state machine replaces unreadable delay() chains with clear logic.

What you need

Arduino UNO board
Push button

Nothing to buy: every component below is simulated in the browser.

Steps

01Declare enum State { GREEN, AMBER, RED };
02Handle transitions with millis() and a switch.
03Each state drives its own outputs.
04Add a pedestrian button that forces the transition.

This tutorial runs inside the Circuitly simulator: your wiring and your code are checked automatically at every step.

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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, Push button. They are already available in the simulator library.
How long does it take?: About 30 minutes, expert level, in 4 guided steps.
What should I know before starting?: The previous tutorial in the series, “Remember after power-off (EEPROM)”, is enough preparation. 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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