4.1.18 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.

Components¶

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 /home/pi/raphael-kit/python/

Step 3: Run the executable file.

sudo python3 4.1.18_GAME_10Second.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. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3
import RPi.GPIO as GPIO
import time
import threading

sensorPin = 26

SDI = 24
RCLK = 23
SRCLK = 18

placePin = (10, 22, 27, 17)
number = (0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 0x80, 0x90)

counter = 0
timer =0
gameState =0

def clearDisplay():
    for i in range(8):
        GPIO.output(SDI, 1)
        GPIO.output(SRCLK, GPIO.HIGH)
        GPIO.output(SRCLK, GPIO.LOW)
    GPIO.output(RCLK, GPIO.HIGH)
    GPIO.output(RCLK, GPIO.LOW)

def hc595_shift(data):
    for i in range(8):
        GPIO.output(SDI, 0x80 & (data << i))
        GPIO.output(SRCLK, GPIO.HIGH)
        GPIO.output(SRCLK, GPIO.LOW)
    GPIO.output(RCLK, GPIO.HIGH)
    GPIO.output(RCLK, GPIO.LOW)

def pickDigit(digit):
    for i in placePin:
        GPIO.output(i,GPIO.LOW)
    GPIO.output(placePin[digit], GPIO.HIGH)

def 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():
    global gameState
    global counter
    global timer1
    if gameState == 0:
        counter = 0
        time.sleep(1)
        timer()
    elif gameState ==1:
        timer1.cancel()
        time.sleep(1)
    gameState = (gameState+1)%2

def loop():
    global counter
    currentState = 0
    lastState = 0
    while True:
        display()
        currentState=GPIO.input(sensorPin)
        if (currentState == 0) and (lastState == 1):
            stateChange()
        lastState=currentState

def timer():
    global counter
    global timer1
    timer1 = threading.Timer(0.01, timer)
    timer1.start()
    counter += 1

def setup():
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(SDI, GPIO.OUT)
    GPIO.setup(RCLK, GPIO.OUT)
    GPIO.setup(SRCLK, GPIO.OUT)
    for i in placePin:
        GPIO.setup(i, GPIO.OUT)
    GPIO.setup(sensorPin, GPIO.IN)

def destroy():   # When "Ctrl+C" is pressed, the function is executed.
    GPIO.cleanup()
    global timer1
    timer1.cancel()

if __name__ == '__main__':  # Program starting from here
    setup()
    try:
        loop()
    except KeyboardInterrupt:
        destroy()

Code Explanation

def stateChange():
    global gameState
    global counter
    global timer1
    if gameState == 0:
        counter = 0
        time.sleep(1)
        timer()
    elif gameState ==1:
        timer1.cancel()
        time.sleep(1)
    gameState = (gameState+1)%2

The game is divided into two modes:

gameState==0 is the “start” mode, in which the time is timed and displayed on the segment display, and the tilting switch is shaken to enter the “show” mode.

gameState==1 is the “show” mode, which stops the timing and displays the time on the segment display. Shaking the tilt switch again will reset the timer and restart the game.

def loop():
    global counter
    currentState = 0
    lastState = 0
    while True:
        display()
        currentState=GPIO.input(sensorPin)
        if (currentState == 0) and (lastState == 1):
            stateChange()
        lastState=currentState

loop() is the main function. First, the time is displayed on the 4-bit segment display and the value of the tilt switch is read. If the state of the tilt switch has changed, stateChange() is called.

def timer():
    global counter
    global timer1
    timer1 = threading.Timer(0.01, timer)
    timer1.start()
    counter += 1

After the interval reaches 0.01s, the timer function is called; add 1 to counter, and the timer is used again to execute itself repeatedly every 0.01s.