6.6 Digital Dice

This project builds upon the 2.5 Number Display 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:

Name	ITEMS IN THIS KIT	LINK
ESP32 Starter Kit	320+	ESP32 Starter Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION	PURCHASE LINK
ESP32 WROOM 32E	BUY
ESP32 Camera Extension	-
Breadboard	BUY
Jumper Wires	BUY
74HC595	BUY
7-segment Display	BUY
Button	BUY

Schematic

This project builds upon the 2.5 Number Display 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

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.

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.