Need single updating plot

[Chamath Vithanawasam]

So I am new to pyqtgraph and I need to collect 20 values from a GPIO pin and then update it into a graph. This needs to keep happening repeatedly as fast as possible. I managed to get it to happen on a loop, only problem is a new plot opens every time. Any way of making sure the same plot is reused?

My code is as shown.

# Simple example of reading the MCP3008 analog input channels and printing
# them all out.
import time
import os


# Import SPI library (for hardware SPI) and MCP3008 library.
import Adafruit_GPIO.SPI as SPI
import Adafruit_MCP3008


# include RPi libraries in to Python code
import RPi.GPIO as GPIO
import time
from time import sleep


##BELOW ARE STUFF ASSOCIATED WITH THE PLOTTING

from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
import pyqtgraph as pg


#-------------------------------------------#


# Software SPI configuration:
#CLK  = 18
#MISO = 23
#MOSI = 24
#CS   = 25
#mcp = Adafruit_MCP3008.MCP3008(clk=CLK, cs=CS, miso=MISO, mosi=MOSI)


# Hardware SPI configuration:
SPI_PORT   = 0
SPI_DEVICE = 0
mcp = Adafruit_MCP3008.MCP3008(spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE))


#QtGui.QApplication.setGraphicsSystem('raster')
app = QtGui.QApplication([])
#mw = QtGui.QMainWindow()
#mw.resize(800,800)


#-------------------------------------------#

pg.setConfigOptions(antialias=True)

def updateSensor1():
   
    global newArray, values, data, reshaped
    newArray = []
   
    for x in range(20):
        values = [0]*8
        #for i in range(8):
        #The read_adc function will get the value of the specified channel (0-7).
        values[0] = mcp.read_adc(0)
        # Print the ADC values.
               
        print('Current value is')
        print(values[0])
               
        newArray.append([values[0]])
        print(newArray)
               
        time.sleep(0.05)


        ##ranArray = np.random
    ranArray = np.asarray(newArray)
    data = np.asarray(newArray)


    print(data)


    reshaped = np.reshape(data, (20,))
    print(reshaped)


    p6 = pg.PlotWindow(title = "S11")
    finitecurve = pg.PlotDataItem(reshaped, pen=(255, 255, 0))
    p6.addItem(finitecurve)
    p6.show()


timer1 = QtCore.QTimer()
timer1.timeout.connect(updateSensor1)
timer1.start(50)

if __name__ == '__main__':
    import sys
    if sys.flags.interactive != 1 or not hasattr(pg.QtCore, 'PYQT_VERSION'):
        pg.QtGui.QApplication.exec_()

Thanks in advance.

[Carlos Pascual]

Have a look at the "ImageItem - Video" (ImageItem.py) example:

python -m pyqtgraph.examples



On Sunday, February 11, 2018 10:42:28 PM CET 'Chamath Vithanawasam' via

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Carlos Pascual Izarra
Scientific Software Coordinator
Computing Division
ALBA Synchrotron [http://www.albasynchrotron.es]
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E-mail: cpas...@cells.es
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