'''
 01.10 - LED blink with loop

 This sketch shows how to blink an LED connected to GPIO 21 using a loop.

 Components
 ----------
  - ESP32
  - 330Ohm resistor for the LED
  - 5mm LED
  -     Connect anode to GPIO 21
  -     Connect cathode to GND via the resistor
  - Wires
  - Breadboard

 Documentation:
 Pins and GPIO: https://micropython-docs-esp32.readthedocs.io/en/esp32_doc/esp32/quickref.html#pins-and-gpio
 sleep_ms: http://docs.micropython.org/en/latest/library/utime.html?highlight=utime%20sleep#utime.sleep_ms

 Course:
 MicroPython with the ESP32

'''

import time
from machine import Pin

# Define the GPIO pins for the LEDs
led_pins = [21, 19, 18]  # Assuming you have three LEDs connected to GPIO pins 2, 4, and 5

# Initialize the LED pins
leds = [Pin(pin, Pin.OUT) for pin in led_pins]

# Function to alternate the state of LEDs
def alternate_leds():
    for i in range(len(leds)):
        leds[i].on()  # Turn on the current LED
        time.sleep(0.5)  # Wait for a short duration
        leds[i].off()  # Turn off the current LED
        time.sleep(0.1)  # Wait for a short duration

# Main loop
while True:
    alternate_leds()