How do I control GPIO with Python?

Using Python, you can easily control GPIO (General Purpose Input/Output) pins to manage components like LEDs, motors, or sensors. Here’s a step-by-step guide for the Raspberry Pi (also applicable to Arduino with MicroPython).

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1. Prerequisites

✅ Raspberry Pi (running Raspberry Pi OS)
✅ Python 3 (pre-installed)
✅ GPIO library (e.g., RPi.GPIO or gpiozero)
✅ Electronic components (e.g., LED, resistor, button)

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2. Installing GPIO Libraries

A. RPi.GPIO (classic, low-level)

bash

sudo apt update && sudo apt install python3-rpi.gpio

B. gpiozero (simpler, modern)

bash

sudo apt install python3-gpiozero

(Recommended for beginners!)

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3. GPIO Pinout

• The Raspberry Pi has 40 GPIO pins (GPIO2, GPIO3, etc.).

• Use pinout in the terminal or refer to Pinout.xyz.

https://pinout.xyz/resources/raspberry-pi-pinout.png

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4. Example 1: Blinking an LED (using gpiozero)

Circuit Setup

• LED+ → GPIO17 (Pin 11)

• LED- → GND (Pin 9) with a 220Ω resistor

Python Code (led_blink.py)

python

from gpiozero import LED
from time import sleep

led = LED(17)  # GPIO17 (Pin 11)

while True:
    led.on()
    sleep(1)
    led.off()
    sleep(1)

Run with:

bash

python3 led_blink.py

(Press CTRL + C to stop.)

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5. Example 2: Reading a Button (using RPi.GPIO)

Circuit Setup

• Button → GPIO2 (Pin 3) and 3.3V (Pin 1)

• Pull-down resistor (or software pull-down)

Python Code (button_read.py)

python

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)  # Use GPIO numbering (not physical pins)
GPIO.setup(2, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)  # Button on GPIO2

try:
    while True:
        if GPIO.input(2) == GPIO.HIGH:
            print("Button pressed!")
        time.sleep(0.1)
except KeyboardInterrupt:
    GPIO.cleanup()  # Reset GPIO pins

Run with:

bash

python3 button_read.py

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6. Example 3: PWM (Motor/Brightness Control)

Circuit Setup

• LED on GPIO18 (Pin 12) with a resistor

Python Code (pwm_led.py)

python

from gpiozero import PWMLED
from time import sleep

led = PWMLED(18)  # GPIO18 (PWM-capable)

while True:
    led.value = 0.5  # 50% brightness
    sleep(1)
    led.value = 0.1  # 10% brightness
    sleep(1)

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7. Key Commands Overview

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8. Tips & Troubleshooting

🔹 Permission issues? Use sudo or add the user to the gpio group:

bash

sudo usermod -aG gpio $USER

🔹 Wrong pins? Use GPIO.setmode(GPIO.BCM) for GPIO numbering.
🔹 Button debouncing? Use hardware debouncing (capacitor) or software delay.

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Conclusion

With Python and gpiozero/RPi.GPIO, GPIO control is easy to implement—whether for LEDs, motors, or sensors.