In my project with raspberry pi and pyqtgraph. I am trying to plot system
time on x axis which* works great on windows but not on raspbian*. Instead
of showing system time and date it starts updating x axis from 01/01/1970
01:00:00. I am confused how to proceed. heres my code
import pyqtgraph as pg
from pyqtgraph.Qt import QtGui, QtCore
import pyqtgraph.exporters
import time
app = QtGui.QApplication([])
pg.setConfigOption('background', 'w')
win = pg.GraphicsWindow(title="Live Graphs") # creating a window for
graphs
win.resize(1920, 720)
win.setWindowTitle('Condition Monitoring') # Setting up the title
win.ci.setBorder((50, 50, 100))
class CAxisTime(pg.AxisItem):
## Formats axis label to human readable time.
# @param[in] values List of \c time_t.
# @param[in] scale Not used.
# @param[in] spacing Not used.
def tickStrings(self, values, scale, spacing):
strns = []
for x in values:
try:
strns.append(time.strftime("%d-%m-%Y\n %H:%M:%S", time.
localtime(x))) # time_t --> time.struct_time
except ValueError: # Windows can't handle dates before 1970
strns.append('')
return strns
axis1 = CAxisTime(orientation='bottom')
p1 = win.addPlot(axisItems={'bottom': axis1}, title = '<b>Humidity') #
creating the plot for humidity
curve1 = p1.plot(pen = '#00A3E0') # setting up the curve and the color
humC1 = [] # an empty list for humidity values
times1 = [] # an empty time list
indx1 = 0 # variable set to zero
hum = BrickletHumidity(UIDhum, ipcon) # Humidity Bricklet
def updateSensorHum():
global curve1,tempC1, indx1, times1, hum, t0
humidity = hum.get_humidity() # get the value of the relative
humidity from humidity bricklet
dataArray1=str(humidity/10).split(',') # creating a data array and
splitting the values
temp1 = float(dataArray1[0]) # creating a float object of data array
humC1.append(temp1) # appending the humidity values
times1.append(time.time()) # appending the time values
if (indx1 > 250): # if indx1 > 300
humC1.pop(0) # start eliminating the 1st value stored in the
array
times1.pop(0) # start eliminating the time from the x axis
indx1 = indx1 + 1 # increase index by 1
curve1.setData(humC1) # drawing the curve humidity vs time
app.processEvents() #process the events in the created app
def update():
updateSensorHum() # update Humidity Sensor
exporter = pg.exporters.ImageExporter(win.scene()) # export the
image exporter library
exporter.export('ConditionMonitoring.png') # export the file as SVG
timer = pg.QtCore.QTimer() # import timer library
timer.timeout.connect(update) # set the connection with the function to
be update
timer.start(999) # start the timer
I'd be thankful if someone can help me with this as this problem is
bothering me since two days without any solution
Kind regards,
Ajay
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