[英]Creating a Knight Rider style streaming LED with a row of images in Python
我正在用樹莓派和pi-face擴展板學習python。 使用Tkinter,我創建了一個帶有按鈕的Gui,用於操作pi面LED。 在代碼的一部分中,我打開了一個新窗口,其中顯示了一個按鈕以及處於“關閉”狀態的一排LED圖像。 我正在嘗試添加一些代碼,以使該行LED圖像沿着圖像行從左到右以“打開”狀態流式傳輸LED圖像,例如Knight Rider汽車的前燈。 我在while循環中嘗試了一些事情,但是如果沒有很多代碼行就看不到如何實現它。 我認為必須有一種方法可以像增加數字寫入一樣在piface擴展板上創建流式LED。 這是我的代碼...
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()
您不需要線程即可完成如此簡單的任務。 在tkinter中設置持久重復任務非常容易,如果該任務花費的時間不超過幾百毫秒(如果花費的時間更長,則用戶界面將開始滯后)。
基本模式是編寫一個完成某些工作的函數,然后使該函數使用after
再次調用自身。 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)
上面的代碼將創建一個在tkinter的mainloop中運行的無限循環。 只要<some code here... >
花費的時間不長,動畫就會顯得流暢並且您的UI不會太遲鈍。
這是該技術的一個簡單的工作示例。 它使用一個簡單的迭代器來遍歷所有led,但是您可以使用要選擇下一個led點亮的任何算法。 您也可以同時打開或關閉屏幕上的LED和硬件LED,或者打開或關閉多個LED等。
為了使此代碼可復制/粘貼,它使用彩色框架而不是圖像,但是您可以根據需要使用圖像。
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()
可能不完全是您要查找的內容,但是您可以從中得到一些啟發,首先在終端上設置此“ cylon”算法。 LED沒有中間的顏色值,但是我猜想殘余的光線應該可以解決問題。
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)
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