GPIO Pins — What They Are

Relax. We'll talk through this in plain words — no textbook voice.

What you'll walk away with

Understand GPIO pins, no intimidation required
Get comfortable running your own hardware wiring and code
Apply this concept right away in a real project

Let's think about it this way for a moment

Along one edge of the Pi board sit 40 pins arranged in 2 rows — each pin has two numbering systems (physical pin number vs BCM/GPIO number, and when writing code, BCM numbering is what's used almost universally). Each pin can be configured as Output mode (sending voltage from code to switch an LED on/off) or Input mode (reading a button press or a sensor value). There are also power pins (5V, 3.3V) and ground pins (GND) — for the circuit's power source and return path.

Let's connect this to a real-world scenario

Keep a GPIO pin layout diagram handy (a site like pinout.xyz works well) and plan out which pin you'll use for what before you start a project — connecting a power pin directly to a ground pin (a short circuit) can destroy the board, so pay close attention to your wiring diagram.

GPIO = the ability to control the physical world (LEDs, sensors, motors) with code
BCM numbering is the standard used when writing code
Be careful not to short-circuit power/ground pins

Let's look at an example together

text

GPIO pin categories
---------------------
Power pins    → 5V, 3.3V (circuit ကို power ပေး)
Ground pins   → GND (return path)
GPIO pins     → Output (LED on/off) or Input (button/sensor read)

Before wiring: check pinout.xyz for your Pi model's exact layout

You should see

You can tell apart the three GPIO pin categories: Power, Ground, and GPIO.

5-Minute Try-It

Visit the pinout.xyz website (or the documentation) and copy out your Pi model's GPIO layout diagram (physical pin number vs BCM number).

A quick word of caution

It's best to power off the Pi before wiring up any GPIO pins — changing the wiring while power is on risks a short circuit that can damage the board.

Easy traps

Accidentally connecting a power pin (5V) directly to a ground pin, causing a short circuit (which can damage the board)
Mixing up the physical pin number with the BCM/GPIO number and writing the wrong pin into code

Try It Yourself

Visit the pinout.xyz website (or the documentation) and copy out your Pi model's GPIO layout diagram (physical pin number vs BCM number).

You'll know it worked when: You can tell apart the three GPIO pin categories: Power, Ground, and GPIO.