import time
from Displays import *
from Lights import *
from Buzzer import *


"""
In this Tutorial exercise, we are going to build a little Dice Gadget
At the minimum, it should roll and show a number of lights on 
representing the number it rolled.

Leraning objectives:

1. Using lists
2. Creating a subclass of a class
3. Using loops 
4. Expressing logic.


Step 1. Review the classes and do a quick assessment of what classes we have
Light and Dimlight, Buzzer, PassiveBuzzer and ActiveBuzzer, Display and LCDDisplay
- the above classes we have already seen.
We see two new classes today - CompositeLights and TrafficLight.
"""


"""
Step 2. Test some basic creating classes and calling methods.
We are going to create a class called DiceGadget in this application, and it will need
to use the 6 LEDs you see here, 2 buttons - we can call them roll and run. This will 
use the Dice model class that we created earlier.

Step 2A. Create the DiceGadget class, and the constructor to set up all the hardware, and a test
method to check one or 2 things, say turn on a couple LEDs, beep the buzzer, 
and show something on the display.

Step 2B. Add the Button handlers to the Dice class for the roll and run buttons. 
Put something on the display when these buttons are pushed to start with to 
test the handlers.
"""

"""
Step 3. Subclassing the compositeclass.
Turn the DiceGadget class into a subclass of the CompositeLight class.
Le'ts use the compositelights class as a basis for building our dice. examine 
that class and see what it has. We use the array to store our 6 lights.
"""

"""
Step 4. Create the a method that shows the result of a Dice roll. 
You should make use of the model here, so the model takes care of finding
the numeric result of the roll, and the gadget displays it. Let's try to make it 
look nice so if a 5 is rolled, it lights up 5 LEDs, and show something like 
You rolled 5 on the display.
"""

"""
Step 5. Animate the roll.
Let's do a fancy roll - if time permits. When the Green run button is
pushed, we are going to animate the LEDs, and when the green button
is pressed again, it should stop on whichever light it was last on.
"""




if __name__ == '__main__':
  print('Program started')

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
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
        """
            
        print(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 """
        
        print(f"Light: turning on {self._name} light at pin {self._pin}")
        self._led.value(1)

    def off(self):
        """ off: turn the light off """
        
        print(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 """
        
        print(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"""

        print(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 """

        print("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
        print(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
        print(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 """
        
        print(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 """

        print(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
        """
        
        print(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

"""
# Displays.py
# A collection of various text-based displays
# Currently supports 4-digit seven-segment displays - both with a tm1637 backpack
# and without (using PIO)
# And also LCD 1602 displays - both using an i2c backpack as well as GPIO
# Only supports number and basic text displays - PIO 7 seg only supports number
# Author: Arijit Sengupta
"""

from machine import Pin, I2C
import time
from pico_i2c_lcd import I2cLcd

class Display:
    """
    The Display Base class - might not actually be needed
    But here to ensure we do not have a duckTyping problem
    """

    def reset(self):
        print(f"reset NOT IMPLEMENTED in {type(self).__name__}")

    def showNumber(self, number):
        print(f"showNumber NOT IMPLEMENTED! in {type(self).__name__}")

    def showText(self, text):
        print(f"showText NOT IMPLEMENTED! in {type(self).__name__}")

    def scroll(self, text, speed=250):
        print(f"Scroll NOT IMPLEMENTED! in {type(self).__name__}")


class LCDDisplay(Display):
    """
    LCD Display class - currently supports displays with an I2C backpack
    as well as displays directly driven via the d4-d7 pins
    
    Parameters
    --------
    This is important since Python does not have method overloading, we have one init
    to do both parallel as well as i2c displays
    pass rs, e, d4, d5, d6, d7 pin numbers for parallel displays
    
    pass sda, scl, i2cid for i2c displays - default is to use parallel so must pass sda/scl/i2cid
    if using i2c
    
    To connect the display to I2C 0 on GPIO pins 0,1
    usage: LCDDisplay(sda=0, scl=1, i2cid=0)
    
    To connect the display to I2C ID 1 on GPIO pins 2,3
    usage: LCDDisplay(sda=2, scl=3, i2cid=1)
    
    To connect via parallel with rs on pin 5, e on pin 4
    and d4,d5,d6,d7 to pins 3,2,1 and 0:
    usage:  LCDDisplay()  # yeah those are the default so you don't need to send
    usage: LCDDisplay(rs=5, e=4, d4=3, d5=2, d6=1, d7=0) # preferred - you can see how its hooked up
    
    """
    
    def __init__(self, sda=-1, scl=-1, i2cid=0):
        """
        Combined constructor for the direct-driven displays
        explicitly pass in the sda and scl if you need to use I2C
        """
        
        print("LCDDisplay (I2C) Constructor")
        i2c = I2C(i2cid, sda=Pin(sda), scl=Pin(scl), freq=400000)
        try:
            I2C_ADDR = i2c.scan()[0]
            self._lcd = I2cLcd(i2c, I2C_ADDR, 2, 16)
        except:
            raise ValueError('Could not connect to display - check wiring.')

    def reset(self):
        """ 
        clear the display screen
        """
        
        print("LCDDisplay: reset")
        self._lcd.clear()

    def showNumber(self, number, row=0, col=0):
        """
        show a single number
        """
        
        print(f"LCDDisplay - showing number {number} at {row},{col}")
        self._lcd.move_to(col, row)
        self._lcd.putstr(f"{number}")

    def showNumbers(self, num1, num2, colon=True, row=0, col=0):
        """
        Show two numbers optionally separated by a colon
        by default, the colon is shown
        """
        
        print(f"LCDDisplay - showing numbers {num1}, {num2} at {row},{col}")
        self._lcd.move_to(col, row)
        colsym = ":" if colon else " "
        self._lcd.putstr(f"{num1}{colsym}{num2}")

    def showText(self, text, row=0, col=0):
        """
        Show a string - only first 4 characters will be shown
        for anything bigger than 4 characters.
        """
        
        print(f"LCDDisplay - showing text {text} at {row},{col}")
        self._lcd.move_to(col, row)
        self._lcd.putstr(text)

    def scroll(self, text, row=0, speed=100, skip=2):
        """
        A very simple scroll implementation
        Scrolls some text right to left in a row

        speed is essentially the delay between refresh - lower the better
        skip is the number of chars to skip for the next refresh
        higher number will be faster but may be jerky. lower will be smooth
        but slower.

        I2C devices may not have best scrolling performance. Works
        better with GPIO-driven displays
        """

        print(f"LCDDisplay - scrolling text {text} in row {row}")
        for p in range(0,len(text)+skip, skip):
            curst = (text+' '*(16+skip))[p:p+16]
            for c in range(16,0,-1):
                self._lcd.move_to(c-1, row)
                self._lcd.putchar(curst[c-1])
            time.sleep(speed/1000)



Displays.py

"""
# Buzzer.py - Object-oriented implementation of active and passive buzzers
# Author: Arijit Sengupta
"""

import time
from machine import Pin, PWM

class Buzzer:
    """
    A simple buzzer class - use it to play and pause different sounds
    ranging from fequencies 10 through 10000
    default volume is half volume - set it between 0 and 10
    """ 
    
    def beep(self, tone=500, duration=150):
        print(f"Beeping the buzzer at {tone}hz for {duration} ms")
        self.play(tone)
        time.sleep(duration / 1000)
        self.stop()
    
class ActiveBuzzer(Buzzer):
    """
    An active buzzer has an internal oscillator that plays a fixed tone when power is applied
    Cannot control the tone. Only turn on and off.
    """
    
    def __init__(self, pin):
        self._buz = Pin(pin, Pin.OUT)
   
    def play(self, tone=500):
        """ Play sound. Tone is ignored. """
        
        self._buz.value(1)
        
    def stop(self):
        """ Stop the sound. """
        
        self._buz.value(0)
    
class PassiveBuzzer(Buzzer):
    """
    A passive buzzer does not have an internal oscillator. MC needs to send a PWM signal
    to play tones. The tone is controlled by the frequency of the PWM, and the volume level
    is controlled by the duty cycle. Setting duty cycle to 0 stops sound.
    """
    
    def __init__(self, pin):
        print("PassiveBuzzer: constructor")
        self._buz = PWM(Pin(pin))
        self._volume = 5
        self._playing = False
        self.stop()

    def play(self, tone=500):
        """ play the supplied tone. """
        
        print(f"PassiveBuzzer: playing tone {tone}")
        self._buz.freq(tone)
        self._buz.duty_u16(self._volume * 100)
        self._playing = True

    def stop(self):
        """ Stop playing sound """
        
        print("PassiveBuzzer: stopping tone")
        self._buz.duty_u16(0)
        self._playing = False

    def setVolume(self, volume=5):
        """ Change the volume of the sound currently playing and future plays """
        
        print(f"PassiveBuzzer: changing volume to {volume}")
        self._volume = volume
        if (self._playing):
            self._buz.duty_u16(self._volume * 100)


Buzzer.py

"""
# Button.py - Object-Oriented implementation of a Button
# Author: Arijit Sengupta
"""

from machine import Pin
import time

class Button:
    """
    A simple Button class
    Create the button using Button(pinnumber, name, handler)
    handler is typically self, and create two methods buttonPressed and buttonReleased
    to handle the push and release of the button.
    The name of the button will be passed back to the handler to identify
    which button was pressed/released
    """
    
    def __init__(self, pin, name, *, buttonhandler=None, lowActive=True):
        self._pinNo = pin
        self._name = name
        if lowActive:
            self._pin = Pin(pin, Pin.IN, Pin.PULL_UP)
        else:
            self._pin = Pin(pin, Pin.IN, Pin.PULL_DOWN)
        self._debounce_time = 0
        self._lowActive = lowActive
        self._buttonhandler = buttonhandler
        self._pin.irq(trigger = Pin.IRQ_FALLING | Pin.IRQ_RISING, handler = self._callback)

    def isPressed(self):
        """ Check if the button is pressed or not - useful if polling """
        
        return (self._lowActive and self._pin.value() ==0) or (not self._lowActive and self._pin.value() == 1)
    
    def setHandler(self, buttonhandler):
        """ A class that has buttonPressed(name) and buttonReleased(name) methods """
        
        self._buttonhandler = buttonhandler
        
    def _callback(self, pin):
        """ The private interrupt handler - will call appropriate handlers """
        
        t = time.ticks_ms()
        if (t-self._debounce_time) > 100:
            self._debounce_time=t
            if self._buttonhandler is not None:
                if self.isPressed():
                    self._buttonhandler.buttonPressed(self._name)
                else:
                    self._buttonhandler.buttonReleased(self._name)
        self._debounce_time=t


Button.py

"""Source: Instructables, Tom's Hardware and GitHub """
"""Not Authored by Dr. Sengupta """
"""Provides an API for talking to HD44780 compatible character LCDs."""

import time

class LcdApi:
    """Implements the API for talking with HD44780 compatible character LCDs.
    This class only knows what commands to send to the LCD, and not how to get
    them to the LCD.
    It is expected that a derived class will implement the hal_xxx functions.
    """

    # The following constant names were lifted from the avrlib lcd.h
    # header file, however, I changed the definitions from bit numbers
    # to bit masks.
    #
    # HD44780 LCD controller command set

    LCD_CLR = 0x01              # DB0: clear display
    LCD_HOME = 0x02             # DB1: return to home position

    LCD_ENTRY_MODE = 0x04       # DB2: set entry mode
    LCD_ENTRY_INC = 0x02        # --DB1: increment
    LCD_ENTRY_SHIFT = 0x01      # --DB0: shift

    LCD_ON_CTRL = 0x08          # DB3: turn lcd/cursor on
    LCD_ON_DISPLAY = 0x04       # --DB2: turn display on
    LCD_ON_CURSOR = 0x02        # --DB1: turn cursor on
    LCD_ON_BLINK = 0x01         # --DB0: blinking cursor

    LCD_MOVE = 0x10             # DB4: move cursor/display
    LCD_MOVE_DISP = 0x08        # --DB3: move display (0-> move cursor)
    LCD_MOVE_RIGHT = 0x04       # --DB2: move right (0-> left)

    LCD_FUNCTION = 0x20         # DB5: function set
    LCD_FUNCTION_8BIT = 0x10    # --DB4: set 8BIT mode (0->4BIT mode)
    LCD_FUNCTION_2LINES = 0x08  # --DB3: two lines (0->one line)
    LCD_FUNCTION_10DOTS = 0x04  # --DB2: 5x10 font (0->5x7 font)
    LCD_FUNCTION_RESET = 0x30   # See "Initializing by Instruction" section

    LCD_CGRAM = 0x40            # DB6: set CG RAM address
    LCD_DDRAM = 0x80            # DB7: set DD RAM address

    LCD_RS_CMD = 0
    LCD_RS_DATA = 1

    LCD_RW_WRITE = 0
    LCD_RW_READ = 1

    def __init__(self, num_lines, num_columns):
        self.num_lines = num_lines
        if self.num_lines > 4:
            self.num_lines = 4
        self.num_columns = num_columns
        if self.num_columns > 40:
            self.num_columns = 40
        self.cursor_x = 0
        self.cursor_y = 0
        self.implied_newline = False
        self.backlight = True
        self.display_off()
        self.backlight_on()
        self.clear()
        self.hal_write_command(self.LCD_ENTRY_MODE | self.LCD_ENTRY_INC)
        self.hide_cursor()
        self.display_on()

    def clear(self):
        """Clears the LCD display and moves the cursor to the top left
        corner.
        """
        self.hal_write_command(self.LCD_CLR)
        self.hal_write_command(self.LCD_HOME)
        self.cursor_x = 0
        self.cursor_y = 0

    def show_cursor(self):
        """Causes the cursor to be made visible."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR)

    def hide_cursor(self):
        """Causes the cursor to be hidden."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)

    def blink_cursor_on(self):
        """Turns on the cursor, and makes it blink."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR | self.LCD_ON_BLINK)

    def blink_cursor_off(self):
        """Turns on the cursor, and makes it no blink (i.e. be solid)."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
                               self.LCD_ON_CURSOR)

    def display_on(self):
        """Turns on (i.e. unblanks) the LCD."""
        self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)

    def display_off(self):
        """Turns off (i.e. blanks) the LCD."""
        self.hal_write_command(self.LCD_ON_CTRL)

    def backlight_on(self):
        """Turns the backlight on.
        This isn't really an LCD command, but some modules have backlight
        controls, so this allows the hal to pass through the command.
        """
        self.backlight = True
        self.hal_backlight_on()

    def backlight_off(self):
        """Turns the backlight off.
        This isn't really an LCD command, but some modules have backlight
        controls, so this allows the hal to pass through the command.
        """
        self.backlight = False
        self.hal_backlight_off()

    def move_to(self, cursor_x, cursor_y):
        """Moves the cursor position to the indicated position. The cursor
        position is zero based (i.e. cursor_x == 0 indicates first column).
        """
        self.cursor_x = cursor_x
        self.cursor_y = cursor_y
        addr = cursor_x & 0x3f
        if cursor_y & 1:
            addr += 0x40    # Lines 1 & 3 add 0x40
        if cursor_y & 2:    # Lines 2 & 3 add number of columns
            addr += self.num_columns
        self.hal_write_command(self.LCD_DDRAM | addr)

    def putchar(self, char):
        """Writes the indicated character to the LCD at the current cursor
        position, and advances the cursor by one position.
        """
        if char == '\n':
            if self.implied_newline:
                # self.implied_newline means we advanced due to a wraparound,
                # so if we get a newline right after that we ignore it.
                pass
            else:
                self.cursor_x = self.num_columns
        else:
            self.hal_write_data(ord(char))
            self.cursor_x += 1
        if self.cursor_x >= self.num_columns:
            self.cursor_x = 0
            self.cursor_y += 1
            self.implied_newline = (char != '\n')
        if self.cursor_y >= self.num_lines:
            self.cursor_y = 0
        self.move_to(self.cursor_x, self.cursor_y)

    def putstr(self, string):
        """Write the indicated string to the LCD at the current cursor
        position and advances the cursor position appropriately.
        """
        for char in string:
            self.putchar(char)

    def custom_char(self, location, charmap):
        """Write a character to one of the 8 CGRAM locations, available
        as chr(0) through chr(7).
        """
        location &= 0x7
        self.hal_write_command(self.LCD_CGRAM | (location << 3))
        self.hal_sleep_us(40)
        for i in range(8):
            self.hal_write_data(charmap[i])
            self.hal_sleep_us(40)
        self.move_to(self.cursor_x, self.cursor_y)

    def hal_backlight_on(self):
        """Allows the hal layer to turn the backlight on.
        If desired, a derived HAL class will implement this function.
        """
        pass

    def hal_backlight_off(self):
        """Allows the hal layer to turn the backlight off.
        If desired, a derived HAL class will implement this function.
        """
        pass

    def hal_write_command(self, cmd):
        """Write a command to the LCD.
        It is expected that a derived HAL class will implement this
        function.
        """
        raise NotImplementedError

    def hal_write_data(self, data):
        """Write data to the LCD.
        It is expected that a derived HAL class will implement this
        function.
        """
        raise NotImplementedError

    def hal_sleep_us(self, usecs):
        """Sleep for some time (given in microseconds)."""
        time.sleep_us(usecs)

lcd_api.py

"""Source: Instructables, Tom's Hardware and GitHub """
"""Not Authored by Dr. Sengupta """

import utime
import gc

from lcd_api import LcdApi
from machine import I2C

# PCF8574 pin definitions
MASK_RS = 0x01       # P0
MASK_RW = 0x02       # P1
MASK_E  = 0x04       # P2

SHIFT_BACKLIGHT = 3  # P3
SHIFT_DATA      = 4  # P4-P7

class I2cLcd(LcdApi):
    
    #Implements a HD44780 character LCD connected via PCF8574 on I2C

    def __init__(self, i2c, i2c_addr, num_lines, num_columns):
        self.i2c = i2c
        self.i2c_addr = i2c_addr
        self.i2c.writeto(self.i2c_addr, bytes([0]))
        utime.sleep_ms(20)   # Allow LCD time to powerup
        # Send reset 3 times
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
        utime.sleep_ms(5)    # Need to delay at least 4.1 msec
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
        utime.sleep_ms(1)
        self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
        utime.sleep_ms(1)
        # Put LCD into 4-bit mode
        self.hal_write_init_nibble(self.LCD_FUNCTION)
        utime.sleep_ms(1)
        LcdApi.__init__(self, num_lines, num_columns)
        cmd = self.LCD_FUNCTION
        if num_lines > 1:
            cmd |= self.LCD_FUNCTION_2LINES
        self.hal_write_command(cmd)
        gc.collect()

    def hal_write_init_nibble(self, nibble):
        # Writes an initialization nibble to the LCD.
        # This particular function is only used during initialization.
        byte = ((nibble >> 4) & 0x0f) << SHIFT_DATA
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        gc.collect()
        
    def hal_backlight_on(self):
        # Allows the hal layer to turn the backlight on
        self.i2c.writeto(self.i2c_addr, bytes([1 << SHIFT_BACKLIGHT]))
        gc.collect()
        
    def hal_backlight_off(self):
        #Allows the hal layer to turn the backlight off
        self.i2c.writeto(self.i2c_addr, bytes([0]))
        gc.collect()
        
    def hal_write_command(self, cmd):
        # Write a command to the LCD. Data is latched on the falling edge of E.
        byte = ((self.backlight << SHIFT_BACKLIGHT) |
                (((cmd >> 4) & 0x0f) << SHIFT_DATA))
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        byte = ((self.backlight << SHIFT_BACKLIGHT) |
                ((cmd & 0x0f) << SHIFT_DATA))
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        if cmd <= 3:
            # The home and clear commands require a worst case delay of 4.1 msec
            utime.sleep_ms(5)
        gc.collect()

    def hal_write_data(self, data):
        # Write data to the LCD. Data is latched on the falling edge of E.
        byte = (MASK_RS |
                (self.backlight << SHIFT_BACKLIGHT) |
                (((data >> 4) & 0x0f) << SHIFT_DATA))
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        byte = (MASK_RS |
                (self.backlight << SHIFT_BACKLIGHT) |
                ((data & 0x0f) << SHIFT_DATA))      
        self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
        self.i2c.writeto(self.i2c_addr, bytes([byte]))
        gc.collect()

pico_i2c_lcd.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
import array, time
from machine import Pin
import rp2

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 """

        print("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
        """
        
        print("CompositeLight: turning on all lights")
        for l in self._lights:
            l.on()

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

        print("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) """

        print(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, green, yellow, red):
        """
        # Traffic light constructor
        # Add the green, yellow and red lights to the array
        # in that order.
        """
        
        print("TrafficLight constructor: add the lights in order")
        super().__init__()
        self._lights.append(green)
        self._lights.append(yellow)
        self._lights.append(red)
    
    def go(self):
        print("Trafficlight - go/green")
        self.singleOn(0)
    
    def caution(self):
        print("Trafficlight - caution/yellow")
        self.singleOn(1)

    def stop(self):
        print("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()
        print("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()

