LED Traffic Light

Starter code

"""
LEVEL 5 - PYFIRMATA2
Starter: LED Traffic Light (Arduino required)

Hardware needed: Arduino board (with Firmata firmware uploaded) +
3 LEDs (red, yellow, green) with resistors, wired to digital pins 8, 9, 10.
If you don't have hardware, read through the code and talk through the
logic with your instructor - or ask your AI tool to explain each line.

Run with: python starter_pyfirmata_led.py
"""
from pyfirmata2 import Arduino
import time

PORT = Arduino.AUTODETECT   # or type your port manually e.g. "COM3" / "/dev/cu.usbmodem14101"

board = Arduino(PORT)
print("Connected to Arduino on:", board.get_port())

red = board.get_pin('d:8:o')     # digital pin 8, output
yellow = board.get_pin('d:9:o')  # digital pin 9, output
green = board.get_pin('d:10:o')  # digital pin 10, output

def all_off():
    red.write(0)
    yellow.write(0)
    green.write(0)

def traffic_light_cycle():
    all_off()
    green.write(1)
    print("GREEN - go!")
    time.sleep(4)

    green.write(0)
    yellow.write(1)
    print("YELLOW - slow down!")
    time.sleep(2)

    yellow.write(0)
    red.write(1)
    print("RED - stop!")
    time.sleep(4)

    red.write(0)

try:
    while True:
        traffic_light_cycle()
except KeyboardInterrupt:
    all_off()
    board.exit()
    print("Stopped. Board disconnected safely.")


# ---------------------------------------------------------------
# LEVEL UP! Try one (or more) of these upgrades:
# 1. Add a push button (digital input) that lets a "pedestrian" trigger
#    the light to change early.
# 2. Add a buzzer that beeps during the yellow light.
# 3. Read an analog sensor (like a light sensor) and change LED
#    behavior based on real-world brightness.
# 4. Make the timing adjustable with variables at the top of the file.
# 5. Combine this with the guizero app (Level 2) - add buttons in a
#    GUI window that control the LEDs instead of using code only.
# 6. Ask your AI tool: "How do I read a button press with pyfirmata2
#    and use it to change my program's behavior?"
# ---------------------------------------------------------------