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
pyqtgraph wrote:
> 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 Izarra
Scientific Software Coordinator
Computing Division
ALBA Synchrotron [http://www.albasynchrotron.es]
Carrer de la Llum 2-26
E-08290 Cerdanyola del Valles (Barcelona), Spain
E-mail: [email protected]
Phone: +34 93 592 4428
+----------------------------------------------------+
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