Stehe vor einem kleinen Problem (und vermute das die Lösung für einen erfahreneren Programmierer ganz einfach ist.
).Ich möchte mit einem Raspberry Pi und Python bzw PyQt eine kleine Temperaturregelung realisieren. Abgesehen von der weiteren Baustelle, dem Regler und dem dafür notwendigen Threading, möchte ich nun zunächst lediglich die gemessene Temperatur im lcdNumber Display des GUI anzeigen.
Das ganze wird auf dem Raspberry über das start.py Skript direkt im XServer gestartet und ergibt auf dem Adafruit Display ein wunderschönes Fenster mit LCD Anzeige
Kann mir bitte jemand helfen wie ich die Programme verknüpfen kann um die vom Thermoelement ermittelte Temperatur "tc" am Ende des temp.py Codes an das lcdNumber Display der GUI zu übergeben?
Separat in der Konsole gestartet funktioniert das per SPI bit banging an den GPIO Pins 22, 23 und 27 angeschlossene Thermoelement mit dem letzten Codeblock temp.py einwandfrei.
Vielen Dank schon mal im voraus!!
Mit PyQt habe ich folgende GUI erstellt:
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# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'main.ui'
#
# Created: Mon May 26 14:27:45 2014
# by: PyQt4 UI code generator 4.10.4
#
# WARNING! All changes made in this file will be lost!
from PyQt4 import QtCore, QtGui
try:
_fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
def _fromUtf8(s):
return s
try:
_encoding = QtGui.QApplication.UnicodeUTF8
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
def _translate(context, text, disambig):
return QtGui.QApplication.translate(context, text, disambig)
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(320, 240)
MainWindow.setCursor(QtGui.QCursor(QtCore.Qt.BlankCursor))
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.lcdNumber = QtGui.QLCDNumber(self.centralwidget)
self.lcdNumber.setGeometry(QtCore.QRect(200, 30, 101, 41))
font = QtGui.QFont()
font.setPointSize(16)
font.setBold(True)
font.setWeight(75)
self.lcdNumber.setFont(font)
self.lcdNumber.setCursor(QtGui.QCursor(QtCore.Qt.BlankCursor))
self.lcdNumber.setLayoutDirection(QtCore.Qt.LeftToRight)
self.lcdNumber.setAutoFillBackground(False)
self.lcdNumber.setFrameShape(QtGui.QFrame.NoFrame)
self.lcdNumber.setLineWidth(1)
self.lcdNumber.setMidLineWidth(0)
self.lcdNumber.setSmallDecimalPoint(False)
self.lcdNumber.setMode(QtGui.QLCDNumber.Dec)
self.lcdNumber.setObjectName(_fromUtf8("lcdNumber"))
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 320, 21))
self.menubar.setObjectName(_fromUtf8("menubar"))
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName(_fromUtf8("statusbar"))
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))Code: Alles auswählen
'''
Created on 26.05.2014
@author: julian
'''
#!/usr/bin/python
import sys
from PyQt4 import QtGui
from main import Ui_MainWindow
class Main(QtGui.QMainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
window = Main()
window.show()
sys.exit(app.exec_())
Code: Alles auswählen
'''
Created on 03.06.2014
@author: julian
'''
#!/usr/bin/python
import RPi.GPIO as GPIO
class MAX31855(object):
def __init__(self, cs_pin, clock_pin, data_pin, units = "c", board = GPIO.BCM):
self.cs_pin = cs_pin
self.clock_pin = clock_pin
self.data_pin = data_pin
self.units = units
self.data = None
self.board = board
# Initialize needed GPIO
GPIO.setmode(self.board)
GPIO.setup(self.cs_pin, GPIO.OUT)
GPIO.setup(self.clock_pin, GPIO.OUT)
GPIO.setup(self.data_pin, GPIO.IN)
# Pull chip select high to make chip inactive
GPIO.output(self.cs_pin, GPIO.HIGH)
def get(self):
'''Reads SPI bus and returns current value of thermocouple.'''
self.read()
self.checkErrors()
return getattr(self, "to_" + self.units)(self.data_to_tc_temperature())
def get_rj(self):
'''Reads SPI bus and returns current value of reference junction.'''
self.read()
return getattr(self, "to_" + self.units)(self.data_to_rj_temperature())
def read(self):
'''Reads 32 bits of the SPI bus & stores as an integer in self.data.'''
bytesin = 0
# Select the chip
GPIO.output(self.cs_pin, GPIO.LOW)
# Read in 32 bits
for i in range(32):
GPIO.output(self.clock_pin, GPIO.LOW)
bytesin = bytesin << 1
if (GPIO.input(self.data_pin)):
bytesin = bytesin | 1
GPIO.output(self.clock_pin, GPIO.HIGH)
# Unselect the chip
GPIO.output(self.cs_pin, GPIO.HIGH)
# Save data
self.data = bytesin
def checkErrors(self, data_32 = None):
'''Checks error bits to see if there are any SCV, SCG, or OC faults'''
if data_32 is None:
data_32 = self.data
anyErrors = (data_32 & 0x10000) != 0 # Fault bit, D16
noConnection = (data_32 & 1) != 0 # OC bit, D0
shortToGround = (data_32 & 2) != 0 # SCG bit, D1
shortToVCC = (data_32 & 4) != 0 # SCV bit, D2
if anyErrors:
if noConnection:
raise MAX31855Error("No Connection")
elif shortToGround:
raise MAX31855Error("Thermocouple short to ground")
elif shortToVCC:
raise MAX31855Error("Thermocouple short to VCC")
else:
# Perhaps another SPI device is trying to send data?
# Did you remember to initialize all other SPI devices?
raise MAX31855Error("Unknown Error")
def data_to_tc_temperature(self, data_32 = None):
'''Takes an integer and returns a thermocouple temperature in celsius.'''
if data_32 is None:
data_32 = self.data
tc_data = ((data_32 >> 18) & 0x3FFF)
return self.convert_tc_data(tc_data)
def data_to_rj_temperature(self, data_32 = None):
'''Takes an integer and returns a reference junction temperature in celsius.'''
if data_32 is None:
data_32 = self.data
rj_data = ((data_32 >> 4) & 0xFFF)
return self.convert_rj_data(rj_data)
def convert_tc_data(self, tc_data):
'''Convert thermocouple data to a useful number (celsius).'''
if tc_data & 0x2000:
# two's compliment
without_resolution = ~tc_data & 0x1FFF
without_resolution += 1
without_resolution *= -1
else:
without_resolution = tc_data & 0x1FFF
return without_resolution * 0.25
def convert_rj_data(self, rj_data):
'''Convert reference junction data to a useful number (celsius).'''
if rj_data & 0x800:
without_resolution = ~rj_data & 0x7FF
without_resolution += 1
without_resolution *= -1
else:
without_resolution = rj_data & 0x7FF
return without_resolution * 0.0625
def to_c(self, celsius):
'''Celsius passthrough for generic to_* method.'''
return celsius
def to_k(self, celsius):
'''Convert celsius to kelvin.'''
return celsius + 273.15
def to_f(self, celsius):
'''Convert celsius to fahrenheit.'''
return celsius * 9.0/5.0 + 32
def cleanup(self):
'''Selective GPIO cleanup'''
GPIO.setup(self.cs_pin, GPIO.IN)
GPIO.setup(self.clock_pin, GPIO.IN)
class MAX31855Error(Exception):
def __init__(self, value):
self.value = value
def __str__(self):
return repr(self.value)
if __name__ == "__main__":
# Multi-chip example
import time
import os
cs_pins = [27]
clock_pin = 23
data_pin = 22
units = "c"
thermocouples = []
for cs_pin in cs_pins:
thermocouples.append(MAX31855(cs_pin, clock_pin, data_pin, units))
running = True
while(running):
try:
for thermocouple in thermocouples:
rj = thermocouple.get_rj()
try:
tc = thermocouple.get()
except MAX31855Error as e:
tc = "Error: "+ e.value
running = True
os.system('clear')
print("tc: {} and rj: {}".format(tc, rj))
time.sleep(1)
except KeyboardInterrupt:
running = False
for thermocouple in thermocouples:
thermocouple.cleanup()
