使用 pyserial 和 matplotlib 实时绘图 [英] live plotting using pyserial and matplotlib
问题描述
我可以通过pyserial从串口设备抓取数据，此时我只能将数据导出到文本文件，文本文件格式如下，它有3列
I can capture data from serial device via pyserial, at this time I can only export data to text file, the text file has format like below, it's have 3 columns
>21 21 0
>
>41 41 0.5
>
>73 73 1
>
....
>2053 2053 5
>
>2084 2084 5.5
>
>2125 2125 6
现在我想用matplotlib来生成live图有2个图(x,y) x,y是第二列和第三列，第一列，'>'，行没有数据可以删除
Now I want to use matplotlib to generate live graph has 2 figure (x,y) x,y are second and third column, first comlumn,'>', and lines don't have data can be remove
谢谢大家！
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更新:今天，在遵循
http://www.blendedtechnologies.com/realtime-plot-of-arduino-serial-data-using-python/231http://eli.thegreenplace.net/2008/08/01/matplotlib-with-wxpython-guispyserial - 如何读取从串行发送的最后一行设备
现在我可以使用线程进行绘图，但是 eliben 说这个 Guis 每次只绘制单个值，这给我带来了很大的限制，因为我的目的是绘制 2 或 3 列，这里的代码是从 blendedtechnologies 修改的
now I can live plot with threading but eliben said that this Guis only plot single value each time, that lead to me the very big limitation, beacause my purpose is plotting 2 or 3 column, here is the code was modified from blendedtechnologies
这是串行处理程序:从线程导入线程
Here is serial handler : from threading import Thread
import time
import serial
last_received = ''
def receiving(ser):
global last_received
buffer = ''
while True:
buffer = buffer + ser.read(ser.inWaiting())
if '\n' in buffer:
lines = buffer.split('\n') # Guaranteed to have at least 2 entries
last_received = lines[-2]
#If the Arduino sends lots of empty lines, you'll lose the
#last filled line, so you could make the above statement conditional
#like so: if lines[-2]: last_received = lines[-2]
buffer = lines[-1]
class SerialData(object):
def __init__(self, init=50):
try:
self.ser = ser = serial.Serial(
port='/dev/ttyS0',
baudrate=9600,
bytesize=serial.EIGHTBITS,
parity=serial.PARITY_NONE,
stopbits=serial.STOPBITS_ONE,
timeout=0.1,
xonxoff=0,
rtscts=0,
interCharTimeout=None
)
except serial.serialutil.SerialException:
#no serial connection
self.ser = None
else:
Thread(target=receiving, args=(self.ser,)).start()
def next(self):
if not self.ser:
return 100 #return anything so we can test when Arduino isn't connected
#return a float value or try a few times until we get one
for i in range(40):
raw_line = last_received[1:].split(' ').pop(0)
try:
return float(raw_line.strip())
except ValueError:
print 'bogus data',raw_line
time.sleep(.005)
return 0.
def __del__(self):
if self.ser:
self.ser.close()
if __name__=='__main__':
s = SerialData()
for i in range(500):
time.sleep(.015)
print s.next()
对我来说，我修改了这个段，以便它可以获取我的第一列数据
For me I modified this segment so it can grab my 1st column data
for i in range(40):
raw_line = last_received[1:].split(' ').pop(0)
try:
return float(raw_line.strip())
except ValueError:
print 'bogus data',raw_line
time.sleep(.005)
return 0.
并根据这些函数在GUI文件上生成图形
and generate graph base on these function on the GUI file
from Arduino_Monitor import SerialData as DataGen
def __init__(self):
wx.Frame.__init__(self, None, -1, self.title)
self.datagen = DataGen()
self.data = [self.datagen.next()]
......................................
................................................
def init_plot(self):
self.dpi = 100
self.fig = Figure((3.0, 3.0), dpi=self.dpi)
self.axes = self.fig.add_subplot(111)
self.axes.set_axis_bgcolor('black')
self.axes.set_title('Arduino Serial Data', size=12)
pylab.setp(self.axes.get_xticklabels(), fontsize=8)
pylab.setp(self.axes.get_yticklabels(), fontsize=8)
# plot the data as a line series, and save the reference
# to the plotted line series
#
self.plot_data = self.axes.plot(
self.data,
linewidth=1,
color=(1, 1, 0),
)[0]
所以我的下一个问题是如何实时抓取至少 2 列并将 2 列的数据传递给可以生成 2 轴图形的 GUI.
So my next question is how to realtime grab at least 2 column and passing 2 columns'data to the GUIs that it can generate graph with 2 axis.
self.plot_data.set_xdata(np.arange(len(self.data))) #my 3rd column data
self.plot_data.set_ydata(np.array(self.data)) #my 2nd column data
推荐答案
好吧，这会读取您的字符串并将数字转换为浮点数.我想您可以根据需要进行调整.
Well, this reads your string and converts the numbers to floats. I assume you'll be able to adapt this as needed.
import numpy as np
import pylab as plt
str = '''>21 21 0
>
>41 41 0.5
>
>73 73 1
>
>2053 2053 5
>
>2084 2084 5.5
>
>2125 2125 6'''
nums = np.array([[float(n) for n in sub[1:].split(' ') if len(n)>0] for sub in str.splitlines() if len(sub)>1])
fig = plt.figure(0)
ax = plt.subplot(2,1,1)
ax.plot(nums[:,0], nums[:,1], 'k.')
ax = plt.subplot(2,1,2)
ax.plot(nums[:,0], nums[:,2], 'r+')
plt.show()
这篇关于使用 pyserial 和 matplotlib 实时绘图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
