Parts

• 1x Raspberry PI
• 1x LED
• 1x 220Ω resistor
• 2x jumper cables

Schematics

Connect the long leg (positive, anode) to pin GPIO23 on Raspberry and the short leg (negative, diode), via a 220Ω resistor to GND.

Python Code

from gpiozero import LED
from time import sleep

led_pin = 23 # BCM
timeout = 0.25  # seconds

led = LED(led_pin)

try:
    while True:
        led.on()
        sleep(timeout)
        led.off()
        sleep(timeout)
except KeyboardInterrupt:
    led.off()