实时绘制光电传感器数据

Question

我正在尝试实时绘制来自光电传感器的数据，无论如何，是否可以通过使用matplotlib来做到这一点？ 我正在尝试找到方法，但没有找到一种方法来直接从GPIO容器中绘制数据而不从txt文件中获取数据。

提前谢谢了

这是我的代码：

#!/usr/local/bin/python

## Reading data from a photocell sensor

import RPi.GPIO as GPIO
import time

# Tell the GPIO library to use Broadcom GPIO references
GPIO.setmode(GPIO.BOARD)

#define the pin that goes to the circuit
Pin = 7

def RCtime (Pin):
  measurement = 0
  #Output on the pin for # Discharge capacitor
  GPIO.setup(Pin, GPIO.OUT)
  GPIO.output(Pin, GPIO.LOW)
  time.sleep(0.0001)

  GPIO.setup(Pin, GPIO.IN)
  # Count loops until voltage across capacitor reads high on GPIO

  while (GPIO.input(Pin) == GPIO.LOW):
    measurement += 1
  return measurement

# Main program loop
i = 1
while True:
    file1 = open("Data%i.txt" %i ,"w")
    i += 1 
    c = 1
    while c <= 50:
        print RCtime (Pin)*1.000
        c += 1
        file1.write(str(RCtime (Pin)))
        file1.write("\n")

    else:
      file1.close()

我编辑了如下代码，现在出现此错误：

  File "/home/pi/Qt_Project/plot.py", line 43
    for RCtime (Pin) in range(0, 500):
SyntaxError: can't assign to function call

新代码：

import RPi.GPIO as GPIO
import time

import matplotlib.pyplot as plt

import threading

GPIO.setmode(GPIO.BOARD)

Pin = 7

threading.Timer(2, RCtime (Pin)).start()

def RCtime (Pin):
    measurement = 0
    GPIO.setup(Pin, GPIO.OUT)
    GPIO.output(Pin, GPIO.LOW)
    time.sleep(0.0001)

    GPIO.setup(Pin, GPIO.IN)

    while (GPIO.input(Pin) == GPIO.LOW):
        measurement += 1
    return measurement


i = 1
while True:
    file1 = open("Data%i.txt" %i ,"w")
    i += 1 
    c = 1
    while c <= 50:
        print RCtime (Pin)*1.000
        c += 1
        file1.write(str(RCtime (Pin)))
        file1.write("\n")

    else:
        file1.close()


figure, axis = plt.subplots(figsize=(9, 9))

for RCtime (Pin) in range(0, 500):
    axis.plot(time.time(), RCtime (Pin), '0-')


plt.show()

Answer 1

为什么不这样

import matplotlib.pyplot as plt

figure, axis = plt.subplots(figsize=(7.6, 6.1))

for x in range(0, 500):
    axis.plot(x, x*2, 'o-')

plt.show()

结合

import threading
threading.Timer(2, RCtime (Pin)).start() #calls func "RCtime" every 2 sec

或执行自我递归（以避免递归深度超过..）

向眼镜蛇博士致意