import time
time.sleep(0.1) # Wait for USB to become ready

print("Hello, Pi Pico!")

from TrafficLight import *

# Create the trafficlight object
tl = PixelTrafficLight(3, 4, 5)

# Operate the TrafficLight forever
while True:
    tl.operate(gtime=4, ytime=1, rtime=3)

main.py

diagram.json

"""
# Lights.py
# implementation of different types of lights
# both digitally controlled (on/off)
# or PWM-controlled (dimming) to set brightness
# Author: Arijit Sengupta
"""

import utime
from machine import Pin, PWM
from Log import *
import _thread
MAX = 65535

baton = _thread.allocate_lock()

class Light:
    """
    The Light base class - just an LED controlled by a digital IO
    Pin. Save the pin in an instance variable
    """
    
    def __init__(self, pin, name="Unnamed"):
        """
        Light constructor - save the pin and set it to OUTPUT mode
        pin is the NUMBER of the pin that the LED is connected to. So
        if connecting to GP21, pass the value 21 to pin        
        name is an optional name of the light
        """
            
        Log.i(f"Light: constructor")
        self._name = name
        self._pin = pin
        self._blinking = False
        self._led = Pin(self._pin, Pin.OUT)  # We need this to use the IO functions

    def on(self):
        """ on: Turn the light on """
        
        Log.i(f"Light: turning on {self._name} light at pin {self._pin}")
        self._led.value(1)

    def off(self):
        """ off: turn the light off """
        
        Log.i(f"Light: turning off {self._name} light at pin {self._pin}")
        self._led.value(0)

    def flip(self):
        """ flip: turn off if it was on, on if it was off """
        
        Log.i(f"Light: Toggling {self._name} light at pin {self._pin}")
        self._led.toggle()

    def blink(self, delay=0.5, times=1):
        """ blink: turn on for delay sec, off for delay sec [times] times"""

        Log.i(f"Light: Blink {self._name} {times} times for {delay} sec")
        for x in range(0,times):
            self.on()
            utime.sleep(delay)
            self.off()
            utime.sleep(delay)


class DimLight(Light):
    """
    The Dimmable Light subclass - will have the standard on off methods
    and in addition will have the ability to set brightness
    """

    def __init__(self, pin, name="Unnamed"):
        """ Dimmable light constructor """

        Log.i("Dimmable light constructor")
        super().__init__(pin, name)
        self._pwm = PWM(self._led)  # Create an instance of PWM object (pulse-width modulation)
        self._pwm.freq(100000)   # set frequency to 100 khz
        self._onState = False
        self._running = False

    def on(self):
        """ Turn on - full brightness max is 255 """
        
        self._running = False
        self._onState = True
        Log.i(f"Dimlight: turn Light {self._name} on (full brightness)")
        self.setBrightness(MAX)

    def off(self):
        """  Turn off - set brightness to 0 """
        
        self._running = False
        self._onState = False
        Log.i(f"Dimlight - turn Light {self._name} off (brightness 0)")
        self.setBrightness(0)

    def flip(self):
        """ flip: turn off if it was on, on if it was off """
        
        Log.i(f"Light: Toggling {self._name} light at pin {self._pin}")
        if self._onState:
            self.off()
        else:
            self.on()       
        
    def setBrightness(self, brightness):
        """ Set brightness to a specific level 0-255 """

        Log.i(f"Dimlight: setting Light {self._name} brightness to {brightness}")
        if (brightness == MAX):
            self._pwm.duty_u16(MAX)
        else:
            self._pwm.duty_u16(brightness * brightness)
        
        if brightness < 50:
            self._onState = False
        else:
            self._onState = True

    def upDown(self):
        """
        # Do a quick demo of going up and down full brightness levels
        # Here it is better to use ChangeDutyCycle
        """
        
        Log.i(f"Dimlight: do an up-down demo on Light {self._name}")
        self._running = True
        dc = 0
        for i in range (0, 25):
            if not self._running:
                break
            dc += 10
            self.setBrightness(dc)
            utime.sleep_ms(100)

        for i in range (0, 25):
            if not self._running:
                break
            dc -= 10
            self.setBrightness(dc)
            utime.sleep_ms(100)
        self._running = False

Lights.py

"""
Log.py - a simplistic Logging process. Built to kind of mimic the
Android Logging process, but at the same time having a global level
set to see the types of logs being displayed.

Basic usage:

Log.level = DEBUG  # set global log level

# Options are: ALL/INFO (everything) DEBUG (debug and higher), ERRO (only errors)
Log.i(f'help')     # Info message: f-strings recommended for showing variables
Log.d(f'value: {v}') # Debug message
Log.e(f'Exception: {x}') # Error message
Log.name('Myproject') # Set a global project name
"""

""" Debug levels """
ALL = 4  # All messages are displayed
INFO = 3  # Basically the same as ALL - for future-proofing
DEBUG = 2  # Info is hidden - debug and higher shown
ERROR = 1  # Only error messages shown
NONE = 0  # No messages are shown from log classes


class Log:

    name = ''
    level = ALL

    @classmethod
    def i(cls, message):
        if (cls.level >= INFO):
            Log.pr(message)

    @classmethod
    def d(cls, message):
        if (cls.level >= DEBUG):
            Log.pr(message)

    @classmethod
    def e(cls, message):
        if (cls.level >= ERROR):
            Log.pr(message)

    @classmethod
    def pr(cls, message):
        if cls.name:
            m = cls.name + ": " + message
        else:
            m = message
        print(m)


if __name__ == '__main__':
    print("Hello")
    Log.level = ALL
    Log.name = 'Test'
    Log.i(f'This should print (level: {Log.level})')
    
    Log.level = ERROR
    Log.i(f'This should NOT print (level: {Log.level})')
    Log.e(f'This should print (level: {Log.level})')
    



Log.py

"""
TrafficLight.py - a simple Traffic Light implementation
Author - Jit Sengupta
"""

# Import the modules and files we need
import time
from Lights import *
from CompositeLights import *

class TrafficLight:
    def __init__(self, rpin, ypin, gpin):
        """
        Constructor - initialize the 3 lights and initialize the current light
        """
        self._red = Light(pin=rpin, name="Red")
        self._yellow = Light(pin=ypin, name="Yellow")
        self._green = Light(pin=gpin, name="Green")
        self.stop() # Initialize the current light to red

    def stop(self):
        """
        Set the current light to red
        """
        self._green.off()
        self._yellow.off()
        self._red.on()

    def caution(self):
        """
        Set the current light to yellow
        """
        self._red.off()
        self._green.off()
        self._yellow.on()

    def go(self):
        """
        Set the current light to green
        """
        self._red.off()
        self._yellow.off()
        self._green.on()

    def operate(self, gtime=5, ytime=2, rtime=5):
        """
        Cycle through the lights - start at Green
        then go to Yellow, then Red
        """
        self.go()
        time.sleep(gtime)
        self.caution()
        time.sleep(ytime)
        self.stop()
        time.sleep(rtime)

RED = (255, 0, 0)
GREEN = (0, 255, 0)
YELLOW = (255, 255, 0)

class PixelTrafficLight(TrafficLight):
    def __init__(self, rpin, gpin, bpin):
        self._pixel = Pixel(rpin, gpin, bpin)
        self.stop()

    def stop(self):
        self._pixel.setColor(RED)

    def caution(self):
        self._pixel.setColor(YELLOW)
    
    def go(self):
        self._pixel.setColor(GREEN)

TrafficLight.py

"""
# CompositeLights.py
# A simple inheritance structure showing a fairly abstract CompositeLight
# class that has a set of lights, and two different implementations of it
# Author: Arijit Sengupta
"""

from time import sleep, sleep_ms
from machine import Pin
from Log import *
from Lights import *

class CompositeLight:
    """
    The base CompositeLight class - contains just an array
    and the on, off, run methods that subclasses should potentially override
    The base class simply calls on and off on all internal lights
    that may not be the proper way to turn on the composite
    """
    
    def __init__(self):
        """    # Constructor - just initialize the array of lights """

        Log.i("CompositeLight constructor")
        self._lights = []
        self._running = False
        
    def run(self):
        """
        # Technically this is an abstract method but Python does not
        # correctly support it, so just an empty shell
        """
        
        self._running = True

    def on(self):
        """
        # Turn on all the componets. Note that in does not necessarily
        # get all items in order - but usually does
        """
        
        Log.i("CompositeLight: turning on all lights")
        for l in self._lights:
            l.on()

    def off(self):
        """     # Turn off all the components """

        Log.i("CompositeLight: turning off all lights")
        for l in self._lights:
            l.off()
            
    def singleOn(self, lightno):
        """     # Turn a single light on (and the others off) """

        Log.i(f"CompositieLight - turning only light #{lightno} on")
        for i in range(0,len(self._lights)):
            if i == lightno:
                self._lights[i].on()
            else:
                self._lights[i].off()

    def __str__(self)->str:
        """
        # The __str__ method - add this to any class to generate a 
        # Human readable version of the class
        """
        
        return f"{type(self).__name__} with {len(self._lights)} lights"

        
class TrafficLight(CompositeLight):
    """
    The first subclass of the CompositeLight class
    Has a gree, yellow and red light that need to be
    passed in
    """
    
    def __init__(self, gpin, ypin, rpin):
        """
        # Traffic light constructor
        # Add the green, yellow and red lights to the array
        # in that order.
        """
        
        Log.i("TrafficLight constructor: add the lights in order")
        super().__init__()
        self._lights.append(Light(gpin,'green'))
        self._lights.append(Light(ypin, 'yellow'))
        self._lights.append(Light(rpin, 'red'))
    
    def go(self):
        Log.i("Trafficlight - go/green")
        self.singleOn(0)
    
    def caution(self):
        Log.i("Trafficlight - caution/yellow")
        self.singleOn(1)

    def stop(self):
        Log.i("Trafficlight - stop/red")
        self.singleOn(2)

    def run(self):
        """
        # The run method - just runs the cycle once, showing
        # Green, yellow then red, and going back to Green
        """
        
        super().run()
        Log.i("TrafficLight: Run a simple Green-yellow-red sequence")
        if (self._running):
            self.go()
        if (self._running):
            sleep(3)
        if (self._running):
            self.caution()  
        if (self._running):
            sleep(0.5)
        if (self._running):
            self.stop()
        if (self._running):
            sleep(1.5)
        if (self._running):
            self.go()

class Pixel(CompositeLight):
    """
    The Pixel class - just uses an RGB LED to provide a simple implementation
    of a pixel that can be technically set to any color.
    """        

    def __init__(self, Rpin, Gpin, Bpin, commoncathode = True):
        """     # Pixel constructor """

        Log.i("Pixel: Constructor - add R G B in that order")
        super().__init__()
        self._lights.append(DimLight(Rpin, 'PixelR'))
        self._lights.append(DimLight(Gpin, 'PixelG'))
        self._lights.append(DimLight(Bpin, 'PixelB'))
        self._commoncathode = commoncathode
        self._running = False
        
    def on(self):
        Log.i("Pixel: turning all components on")
        self._running = False
        if self._commoncathode:
            super().on()
        else:
            super().off()
            
    def off(self):
        Log.i("Pixel: turning all components off")
        self._running = False
        if self._commoncathode:
            super().off()
        else:
            super().on()
       
    def setColor(self, color):
        """
        # setColor method - sets to a specific color
        # color is an RGB tuple
        # Brightness is set as percentage in this app
        """
        
        Log.i(f"Pixel: setColor: {color}")
        self._lights[0].setBrightness(color[0])
        self._lights[1].setBrightness(color[1])
        self._lights[2].setBrightness(color[2])
                
    def run(self, delay=250):
        """     # Demo run - just run up and down the R, G, B components """
        self._running = True

        colors = [(255,0,0), (255,165,0), (255,255,0), (0,128,0),(0,0,255),(75,0,130),(238,130,238)]
        Log.i("Pixel - run - rainbow demo")
        for c in colors:
            if not self._running:
                break
            self.setColor(c)
            sleep_ms(delay)        
        self._running = False
