ブレッドボードにボタンを配線する

You've written the code; now make it real. You'll wire a push button on a breadboard so the Arduino can actually feel your press.

A tactile push button has four legs, but they're really just two pairs. Pressing it connects one pair to the other inside.

Straddle the button across the breadboard's center gap. That keeps the two sides separate until a press bridges them together.

Thanks to INPUT_PULLUP, you skip the external resistor entirely. The board holds the pin HIGH for you, so wiring stays tiny.

Run a jumper from one button leg to a digital pin, say pin 2. This is the line the Arduino will read for presses.

Connect the opposite leg to GND. When you press, the pin gets pulled down to ground and your code sees LOW.

Because the legs are paired, wire to ones that sit diagonally across the button. That guarantees you bridge the two real contacts.

Unplug the USB before moving wires. Building with the board powered off avoids shorts and protects the Arduino from mistakes. 🔋

Your sketch must name the same pin you wired. Set pin 2 to INPUT_PULLUP so the software and the hardware agree.

Upload, open the Serial Monitor, and press. Seeing the value drop to 0 confirms your button and wiring both work.

No change on press? Check the diagonal legs, confirm the GND wire, and make sure the code uses the exact pin you plugged into.

Think about where the button's two legs should connect.

You wired a button across the center gap, one leg to pin 2 and one to GND, then confirmed it on Serial. You can now sense the real world! 🎉