Combining an LED and a pushbutton on a Raspberry Pi using Node.js is a great beginner project that teaches you both GPIO input and GPIO output — in JavaScript! 🚀

✅ Goal

🔘 Press the button → 💡 Turn on the LED

🧰 What You Need

🧠 Circuit Wiring

Optional: Use a pull-down resistor (or enable internal one via Node.js)

📦 Install Dependencies

bash
npm init -ynpm install onoff

💻 Code: button-led.js

js
const led = new Gpio(17, 'out');// Setup GPIO27 as input for Button, trigger on both press and releaseconst button = new Gpio(27, 'in', 'both');// Watch for button state changesbutton.watch((err, value) => {  if (err) {    console.error('Error:', err);    return;  }  led.writeSync(value); // If pressed (1), LED on. If released (0), LED off.  console.log('Button state:', value ? 'Pressed' : 'Released');});// Graceful exitprocess.on('SIGINT', () => {  led.writeSync(0);  led.unexport();  button.unexport();  console.log('\nStopped. GPIO cleaned up.');  process.exit();});

🚀 Run the Program

bash
sudo node button-led.js

🔘 When you press the button, the LED turns on
🔁 When you release it, the LED turns off

🔧 Want to Expand?

You can:

• Toggle the LED (instead of momentary)

• Add debounce to prevent bouncing

• Control via web page (express, socket.io)

• Add more LEDs or use a relay to control real devices