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.. _py_dice:

6.6 Digital Dice
================================

This project builds upon the :ref:`py_7_segment` project by adding a button to control the digit displayed on the seven-segment display.

When the button is pressed, the 7-segment display scrolls through the numbers 1-6, and when the button is released, it displays a random number.

This cycle continues each time the button is pressed.

**Required Components**

In this project, we need the following components. 

It's definitely convenient to buy a whole kit, here's the link: 

.. list-table::
    :widths: 20 20 20
    :header-rows: 1

    *   - Name	
        - ITEMS IN THIS KIT
        - LINK
    *   - ESP32 Starter Kit
        - 320+
        - |link_esp32_starter_kit|

You can also buy them separately from the links below.

.. list-table::
    :widths: 30 20
    :header-rows: 1

    *   - COMPONENT INTRODUCTION
        - PURCHASE LINK

    *   - :ref:`cpn_esp32_wroom_32e`
        - |link_esp32_wroom_32e_buy|
    *   - :ref:`cpn_esp32_camera_extension`
        - |link_esp32_extension_board|
    *   - :ref:`cpn_breadboard`
        - |link_breadboard_buy|
    *   - :ref:`cpn_wires`
        - |link_wires_buy|
    *   - :ref:`cpn_74hc595`
        - |link_74hc595_buy|
    *   - :ref:`cpn_7_segment`
        - |link_7segment_buy|
    *   - :ref:`cpn_button`
        - |link_button_buy|

**Schematic**

.. image:: ../../img/circuit/circuit_6.6_electronic_dice.png

This project builds upon the :ref:`py_7_segment` project by adding a button to control the digit displayed on the seven-segment display.

The button is directly connected to IO13 without an external pull-up or pull-down resistor because IO13 has an internal pull-up resistor of 47K, eliminating the need for an additional external resistor.


**Wiring**

.. image:: ../../img/wiring/6.6_DICE_bb.png

**Code**

.. note::

    * Open the ``6.6_digital_dice.py`` file located in the ``esp32-starter-kit-main\micropython\codes`` path, or copy and paste the code into Thonny. Then, click "Run Current Script" or press F5 to execute it.
    * Make sure to select the "MicroPython (ESP32).COMxx" interpreter in the bottom right corner. 




.. code-block:: python

    import machine
    import time
    import random

    # Define the segment code for a common anode 7-segment display
    SEGCODE = [0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f]

    # Initialize the pins for the 74HC595 shift register
    sdi = machine.Pin(25, machine.Pin.OUT)  # DS
    rclk = machine.Pin(27, machine.Pin.OUT)  # STcp
    srclk = machine.Pin(26, machine.Pin.OUT)  # SHcp

    button = machine.Pin(13, machine.Pin.IN) # Button pin

    # Define the hc595_shift function to shift data into the 74HC595 shift register
    def hc595_shift(dat):
        # Set the RCLK pin to low
        rclk.off()
        
        # Iterate through each bit (from 7 to 0)
        for bit in range(7, -1, -1):
            # Extract the current bit from the input data
            value = 1 & (dat >> bit)
            
            # Set the SRCLK pin to low
            srclk.off()
            
            # Set the value of the SDI pin
            sdi.value(value)
            
            # Clock the current bit into the shift register by setting the SRCLK pin to high
            srclk.on()
            
        # Latch the data into the storage register by setting the RCLK pin to high
        rclk.on()

    # Initialize the random seed
    random.seed(time.ticks_us())


    num = 1
    button_state = False

    # Define the button callback function to toggle the button state
    def button_callback(pin):
        global button_state
        button_state = not button_state

    # Attach the button callback function to the falling edge of the button pin
    button.irq(trigger=machine.Pin.IRQ_FALLING, handler=button_callback)

    # Continuously display the current digit on the 7-segment display, scrolling if button is not pressed
    while True:
        
        # Display the current digit on the 7-segment display
        hc595_shift(SEGCODE[num])
        
        # If the button is pressed and button state is True
        if button_state:
            pass

        # If the button is pressed again and button state is False, generate a new random digit
        if not button_state:
            num = random.randint(1, 6)
            time.sleep_ms(10) # Adjust this value to control the display refresh rate
        
While the program is running, pressing the button will make the 7-segment display scroll and randomly display a number between 1 and 6. 

Upon pressing the button again, the 7-segment display will stop and reveal a specific number. Press the button once more, and the 7-segment display will resume scrolling through the digits.