使用matplotlib實時繪製arduino數據時不顯示圖形圖

Question

我想從Arduino UNO的matplotlib模擬輸入中繪製實時講座。 我的問題：該圖不會顯示。只有當我停止運行代碼（Ctrl + C）時，它纔會顯示最後一個值的圖形。

將「print pData」行添加到代碼以檢查值是否正確到達計算機時，它們在python終端上正確顯示（每秒顯示25個值數組）。

#!/usr/bin/python 

from matplotlib import pyplot 
import pyfirmata 
from time import sleep 

# Associate port and board with pyFirmata 
port = '/dev/ttyACM0' 
board = pyfirmata.Arduino(port) 

# Using iterator thread to avoid buffer overflow 
it = pyfirmata.util.Iterator(board) 
it.start() 

# Assign a role and variable to analog pin 0 
a0 = board.get_pin('a:0:i') 

pyplot.ion() 

pData = [0.0] * 25 
fig = pyplot.figure() 
pyplot.title('Real-time Potentiometer reading') 
ax1 = pyplot.axes() 
l1, = pyplot.plot(pData) 
pyplot.ylim([0, 1]) 

while True: 
    try: 
     sleep(1) 
     pData.append(float(a0.read())) 
     pyplot.ylim([0, 1]) 
     del pData[0] 
     l1.set_xdata([i for i in xrange(25)]) 
     l1.set_ydata(pData) # update the data 
     #print pData 
     pyplot.draw() # update the plot 
    except KeyboardInterrupt: 
     board.exit() 
     break 

Answer 1

這是一個使用matplotlib.animation進行實時繪圖的模型。

from matplotlib import pyplot 
import matplotlib.animation as animation 
import random 

# Generate sample data 
class Pin: 
    def read(self): 
     return random.random() 
a0 = Pin() 

n = 25 
pData = [None] * n 

fig, ax = pyplot.subplots() 
pyplot.title('Real-time Potentiometer reading') 
l1, = ax.plot(pData) 
# Display past sampling times as negative, with 0 meaning "now" 
l1.set_xdata(range(-n + 1, 1)) 
ax.set(ylim=(0, 1), xlim=(-n + 1, 0)) 

def update(data): 
    del pData[0] 
    pData.append(float(a0.read())) 
    l1.set_ydata(pData) # update the data 
    return l1, 

ani = animation.FuncAnimation(fig, update, interval=1000, blit=True) 

try: 
    pyplot.show() 
finally: 
    pass 
    #board.exit()