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4.1.13 GAME - 10 Second

Introduction

Next, follow me to make a game device to challenge your concentration. Tie the tilt switch to a stick to make a magic wand. Shake the wand, the 4-digit segment display will start counting, shake again will let it stop counting. If you succeed in keeping the displayed count at 10.00, then you win. You can play the game with your friends to see who is the time wizard.

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
Raphael Kit	337	Raphael Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION	PURCHASE LINK
GPIO Extension Board	BUY
Breadboard	BUY
Jumper Wires	BUY
Resistor	BUY
4-Digit 7-Segment Display	-
74HC595	BUY
Tilt Switch	-

Schematic Diagram

T-Board Name	physical	wiringPi	BCM
GPIO17	Pin 11	0	17
GPIO27	Pin 13	2	27
GPIO22	Pin 15	3	22
SPIMOSI	Pin 19	12	10
GPIO18	Pin 12	1	18
GPIO23	Pin 16	4	23
GPIO24	Pin 18	5	24
GPIO26	Pin 37	25	26

Experimental Procedures

Step 1: Build the circuit.

Step 2: Go to the folder of the code.

cd ~/raphael-kit/python-pi5

Step 3: Run the executable file.

sudo python3 4.1.18_GAME_10Second_zero.py

Shake the wand, the 4-digit segment display will start counting, shake again will let it stop counting. If you succeed in keeping the displayed count at 10.00, then you win. Shake it one more time to start the next round of the game.

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python-pi5. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3

from gpiozero import OutputDevice, Button
import time
import threading

# Initialize the button connected to GPIO 26
sensorPin = Button(26)

# Define GPIO pins connected to the 74HC595 shift register
SDI = OutputDevice(24)   # Serial Data Input
RCLK = OutputDevice(23)  # Register Clock
SRCLK = OutputDevice(18) # Shift Register Clock

# Define GPIO pins for digit selection on the 7-segment display
placePin = [OutputDevice(pin) for pin in (10, 22, 27, 17)]

# Define segment codes for numbers 0 to 9 on the 7-segment display
number = (0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 0x80, 0x90)

# Counter and timer variables
counter = 0
timer1 = None
gameState = 0

def clearDisplay():
    """ Clear all segments on the 7-segment display. """
    for _ in range(8):
        SDI.on()
        SRCLK.on()
        SRCLK.off()
    RCLK.on()
    RCLK.off()

def hc595_shift(data):
    """ Shift data to the 74HC595 shift register to display a digit. """
    for i in range(8):
        SDI.value = 0x80 & (data << i)
        SRCLK.on()
        SRCLK.off()
    RCLK.on()
    RCLK.off()

def pickDigit(digit):
    """ Select which digit to display on the 7-segment display. """
    for pin in placePin:
        pin.off()
    placePin[digit].on()

def display():
    """ Display the current counter value on the 7-segment display. """
    global counter
    clearDisplay()
    pickDigit(0)
    hc595_shift(number[counter % 10])

    clearDisplay()
    pickDigit(1)
    hc595_shift(number[counter % 100 // 10])

    clearDisplay()
    pickDigit(2)
    hc595_shift(number[counter % 1000 // 100] - 0x80)

    clearDisplay()
    pickDigit(3)
    hc595_shift(number[counter % 10000 // 1000])

def stateChange():
    """ Handle state changes for the counter based on button presses. """
    global gameState, counter, timer1
    if gameState == 0:
        counter = 0
        time.sleep(1)
        timer()
    elif gameState == 1 and timer1 is not None:
        timer1.cancel()
        time.sleep(1)
    gameState = (gameState + 1) % 2

def loop():
    """ Main loop to check for button presses and update the display. """
    global counter
    currentState = 0
    lastState = 0
    while True:
        display()
        currentState = sensorPin.value
        if (currentState == 0) and (lastState == 1):
            stateChange()
        lastState = currentState

def timer():
    """ Timer function that increments the counter every 0.01 second. """
    global counter, timer1
    timer1 = threading.Timer(0.01, timer)
    timer1.start()
    counter += 1

try:
    loop()
except KeyboardInterrupt:
    if timer1:
        timer1.cancel()

Code Explanation

1. The script begins by importing necessary modules. The gpiozero library is used for interfacing with GPIO devices like buttons, and time and threading modules may be used for handling timing-related tasks or concurrent operations.

   #!/usr/bin/env python3
   
   from gpiozero import OutputDevice, Button
   import time
   import threading
   

2. Initializes a Button object from the GPIO Zero library, connecting it to GPIO pin 26. This setup allows for the detection of button presses.

   # Initialize the button connected to GPIO 26
   sensorPin = Button(26)
   

3. Initializes GPIO pins connected to the shift register’s Serial Data Input (SDI), Register Clock Input (RCLK), and Shift Register Clock Input (SRCLK).

   # Define GPIO pins connected to the 74HC595 shift register
   SDI = OutputDevice(24)   # Serial Data Input
   RCLK = OutputDevice(23)  # Register Clock
   SRCLK = OutputDevice(18) # Shift Register Clock
   

4. Initializes the pins for each digit of the 7-segment display and defines the binary codes for displaying numbers 0-9.

   # Define GPIO pins for digit selection on the 7-segment display
   placePin = [OutputDevice(pin) for pin in (10, 22, 27, 17)]
   
   # Define segment codes for numbers 0 to 9 on the 7-segment display
   number = (0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 0x80, 0x90)
   

5. Functions to control the 7-segment display. clearDisplay turns off all segments, hc595_shift shifts data into the shift register, and pickDigit activates a specific digit on the display.

   def clearDisplay():
       """ Clear all segments on the 7-segment display. """
       for _ in range(8):
           SDI.on()
           SRCLK.on()
           SRCLK.off()
       RCLK.on()
       RCLK.off()
   
   def hc595_shift(data):
       """ Shift data to the 74HC595 shift register to display a digit. """
       for i in range(8):
           SDI.value = 0x80 & (data << i)
           SRCLK.on()
           SRCLK.off()
       RCLK.on()
       RCLK.off()
   
   def pickDigit(digit):
       """ Select which digit to display on the 7-segment display. """
       for pin in placePin:
           pin.off()
       placePin[digit].on()
   

6. Function to display the current value of the counter on the 7-segment display.

   def display():
       """ Display the current counter value on the 7-segment display. """
       global counter
       clearDisplay()
       pickDigit(0)
       hc595_shift(number[counter % 10])
   
       clearDisplay()
       pickDigit(1)
       hc595_shift(number[counter % 100 // 10])
   
       clearDisplay()
       pickDigit(2)
       hc595_shift(number[counter % 1000 // 100] - 0x80)
   
       clearDisplay()
       pickDigit(3)
       hc595_shift(number[counter % 10000 // 1000])
   

7. Function to handle state changes (start/stop) of the counter based on button presses.

   def stateChange():
       """ Handle state changes for the counter based on button presses. """
       global gameState, counter, timer1
       if gameState == 0:
           counter = 0
           time.sleep(1)
           timer()
       elif gameState == 1 and timer1 is not None:
           timer1.cancel()
           time.sleep(1)
       gameState = (gameState + 1) % 2
   

8. Main loop that continuously checks the button state and updates the display. It calls stateChange when the button state changes.

   def loop():
       """ Main loop to check for button presses and update the display. """
       global counter
       currentState = 0
       lastState = 0
       while True:
           display()
           currentState = sensorPin.value
           if (currentState == 0) and (lastState == 1):
               stateChange()
           lastState = currentState
   

9. Timer function that increments the counter at a regular interval (every 0.01 second).

   def timer():
       """ Timer function that increments the counter every 0.01 second. """
       global counter, timer1
       timer1 = threading.Timer(0.01, timer)
       timer1.start()
       counter += 1
   

10. Executes the main loop and allows for a clean exit from the program using a keyboard interrupt (Ctrl+C).

    try:
        loop()
    except KeyboardInterrupt:
        if timer1:
            timer1.cancel()