使用 Python 中的一行图像创建 Knight Rider 风格的流式 LED

Creating a Knight Rider style streaming LED with a row of images in Python

我正在使用 raspberry pi 和 pi-face 扩展板学习 python。 我使用 Tkinter 创建了一个带有按钮的 Gui 来操作 pi-face LED。在代码的一部分中,我打开了一个新的 window,它显示了一个按钮和一行处于 'off' 状态的 LED 图像。我正在尝试添加一些代码,使 LED 图像行在 'on' 状态下沿着图像行从左到右流式传输 LED 图像,例如 Knight Rider 汽车的前灯。 我已经在 while 循环中尝试了一些东西,但是如果没有很多代码行,我不太明白如何实现它。我认为必须有一种方法可以做到这一点,就像增加数字写入以在 piface 扩展板上创建流式 LED 一样。这是我的代码...

class App2:

    def __init__(self, master):
            self.signal = False    #added to stop thread
            print('self.signal', self.signal)

            self.master=master    # I added this line to make the exit button work
            frame = Frame(master)
            frame.pack()
            Label(frame, text='Turn LED ON').grid(row=0, column=0)
            Label(frame, text='Turn LED OFF').grid(row=0, column=1)

            self.button0 = Button(frame, text='Knight Rider OFF', command=self.convert0)
            self.button0.grid(row=2, column=0)
            self.LED0 = Label(frame, image=logo2)   #added to create a row of images
            self.LED1 = Label(frame, image=logo2)
            self.LED2 = Label(frame, image=logo2)
            self.LED3 = Label(frame, image=logo2)
            self.LED4 = Label(frame, image=logo2)
            self.LED5 = Label(frame, image=logo2)
            self.LED6 = Label(frame, image=logo2)
            self.LED7 = Label(frame, image=logo2)
            self.LED0.grid(row=2, column=1)
            self.LED1.grid(row=2, column=2)
            self.LED2.grid(row=2, column=3)
            self.LED3.grid(row=2, column=4)
            self.LED4.grid(row=2, column=5)
            self.LED5.grid(row=2, column=6)
            self.LED6.grid(row=2, column=7)
            self.LED7.grid(row=2, column=8)

            self.button9 = Button(frame, text='Exit', command=self.close_window)
            self.button9.grid(row=3, column=0)


    def convert0(self, tog=[0]):

        tog[0] = not tog[0]

        if tog[0]:
            print('Knight Rider ON')
            self.button0.config(text='Knight Rider ON')
            t=threading.Thread(target=self.LED)
            t.start()
            self.signal = True    #added to stop thread
            print('self.signal', self.signal)
            print('tog[0]', tog[0])
            self.LED0.config(image = logo)
        else:
            print('Knight Rider OFF')
            self.button0.config(text='Knight Rider OFF')
            self.signal = False   #added to stop thread
            print('self.signal', self.signal)
            print('tog[0]', tog[0])
            self.LED0.config(image = logo2)


    def LED(self):
            while self.signal:   #added to stop thread

                a=0

                while self.signal:   #added to stop thread
                        pfio.digital_write(a,1) #turn on
                        sleep(0.05)
                        pfio.digital_write(a,0) #turn off
                        sleep(0.05)
                        a=a+1

                        if a==7:
                                break

                while self.signal:   #added to stop thread

                        pfio.digital_write(a,1) #turn on
                        sleep(0.05)
                        pfio.digital_write(a,0) #turn off
                        sleep(0.05)
                        a=a-1

                        if a==0:
                                break

    def close_window(self):
            print('Knight Rider OFF')
            print('self.signal', self.signal)
            self.button0.config(text='Knight Rider OFF')
            self.LED0.config(image = logo2)
            self.signal = False   #added to stop thread
            print('self.signal', self.signal)


            sleep(1)
            print('Close Child window')
            self.master.destroy()   # I added this line to make the exit button work

root = Tk()
logo2 = PhotoImage(file="/home/pi/Off LED.gif")
logo = PhotoImage(file="/home/pi/Red LED.gif")

root.wm_title('LED on & off program')
app = App(root)

root.mainloop()

如此简单的任务不需要线程。在 tkinter 中设置持久重复任务非常容易,如果任务不超过几百毫秒(如果花费更长的时间,您的 UI 将开始滞后)。

基本模式是编写一个执行某些工作的函数,然后使用 after 使该函数再次调用自身。例如:

def animate():
    # do something, such as turn an led on or off
    <some code here to turn one led on or off>

    # run this again in 100 ms
    root.after(100, animate)

以上将创建一个在 tkinter 的主循环中运行的无限循环。只要 <some code here... > 不会花太长时间,动画就会显得流畅,你的 UI 也不会迟钝。

例子

这是该技术的一个简单的工作示例。它使用一个简单的迭代器循环遍历 LED,但您可以使用您想要选择下一个 LED 点亮的任何算法。您还可以同时打开或关闭屏幕上的 LED 和硬件 LED,或者打开或关闭多个 LED 等。

为了制作此代码 copy/paste-able,它使用彩色框而不是图像,但如果需要,您可以使用图像。

import tkinter as tk  # Tkinter for python 2
from itertools import cycle

class LEDStrip(tk.Frame):
    segments = 16
    speed = 100 # ms

    def __init__(self, parent):
        tk.Frame.__init__(self, parent)

        leds = []
        for i in range(self.segments):
            led = tk.Frame(self, width=12, height=8, borderwidth=1, 
                           relief="raised", background="black")
            led.pack(side="left", fill="both", expand=True)
            leds.append(led)

        self.current_segment = None
        self.iterator = cycle(leds)

    def animate(self):
        # turn off the current segment
        if self.current_segment:
            self.current_segment.configure(background="black")

        # turn on the next segment
        self.current_segment = next(self.iterator)  # self.iterator.next() for python 2
        self.current_segment.configure(background="red")

        # run again in the future
        self.after(self.speed, self.animate)


root = tk.Tk()
strip = LEDStrip(root)
strip.pack(side="top", fill="x")

# start the loop
strip.animate()

root.mainloop()

可能不是您要找的东西,但您可以从中得到一些启发,先在终端上设置此 "cylon" 算法。 LED 没有中间颜色值,但我想光的剩余感知应该可以解决问题。

import sys,time
shift = lambda l, n=1: l[n:]+l[:n]
c = u' ▁▂▃▄▅▆▇' # possible color values
L = 8           # number of items
B = L*[0]       # indices of items
A = [0] + list(range(7)) + list(range(7,0,-1)) + 6*[0]  # light sequence
C = L*[' ']     # start blank

while 1:
   B[A[0]]=L            # set the most brilliant light 
   for x in range(L):
      B[x]-= 1           # decrease all lights values
      B[x] = max(0,B[x]) # not under 0
      C[x] = c[B[x]]     # get the corresponding 'color'
   A = shift(A,-1)       # shift the array to the right
   sys.stdout.write(('%s%s%s')%(' ',''.join(C[1:]),'\r'))
   time.sleep(0.1)

或者试试那个 https://www.trinket.io/python/79b8a588aa