Updating text file with sensor datas from three different threads

Question

I am getting values from three different sensors connected to Raspberry Pi. I am using a ADC grove to get those data's. I am updating these sensor data with date and time in a text file. The problem is i created three different threads for processing each sensor data and each thread has to update its respective sensor data in the same text file without overwriting it. Currently i can able to update the file with sensor data from a single thread only.

import sys
import time
from PyQt5.QtWidgets import*
from PyQt5.QtGui import*
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import QThread, QObject
from PyQt5.QtCore import pyqtSignal
from grove.i2c import Bus

ADC_DEFAULT_IIC_ADDR = 0X04

ADC_CHAN_NUM = 8

REG_RAW_DATA_START = 0X10
REG_VOL_START = 0X20
REG_RTO_START = 0X30

REG_SET_ADDR = 0XC0


class Pi_hat_adc():
    def __init__(self,bus_num=1,addr=ADC_DEFAULT_IIC_ADDR,parent=None):
        self.parent = parent
        self.bus=Bus(bus_num)
        self.addr=addr
             
    def get_nchan_adc_raw_data(self,n):
        data=self.bus.read_i2c_block_data(self.addr,REG_RAW_DATA_START+n,2)
        val =data[1]<<8|data[0]
        return val
   
ADC = Pi_hat_adc()
class Window(QMainWindow):
    def __init__(self):
        super(Window, self).__init__()
       
        self.pi_hat_adc = Pi_hat_adc(parent=self)
       
      
        self.setGeometry(200,200,400,300)
    
        self.line_edit = QLineEdit("",self)
        self.line_edit.setGeometry(5,80,100,40)
        self.line_edit.setStyleSheet("background-color:White")
        self.line_edit1 = QLineEdit("",self)
        self.line_edit1.setGeometry(5,140,100,40)
        self.line_edit1.setStyleSheet("background-color:White")
        self.line_edit2 = QLineEdit("",self)
        self.line_edit2.setGeometry(5,200,100,40)
        self.line_edit2.setStyleSheet("background-color:White")
        self.myLongTask = TaskThread()
        self.myLongTask1 = TaskThread1()
        self.myLongTask2 = TaskThread2()
        self.myLongTask.notifyProgress.connect(self.on_progress)
        self.myLongTask1.notifyProgress.connect(self.on_progress1)
        self.myLongTask2.notifyProgress.connect(self.on_progress2)
        self.on_start()
       
    def on_start(self):
        self.myLongTask.start()
        self.myLongTask1.start()
        self.myLongTask2.start()
       
    def on_progress(self,y):
        self.line_edit.setText(str(y))
        return
   
    def on_progress1(self,y):
        self.line_edit1.setText(str(y))
        getdatetime = datetime.datetime.now() .strftime("%Y-%m-%d %H:%M:%S")
        fb = open('/home/pi/sensor.txt','a+')
        fb.write('\n')
        fb.write(getdatetime)
        fb.write(" ADC = ")
        fb.write(str(y))
        fb.write('\n')
        fb.close
        return
   
    def on_progress2(self,y):
        self.line_edit2.setText(str(y))
        return

class TaskThread(QtCore.QThread):
    notifyProgress = pyqtSignal(int)
   
    def run(self):
        while True:
            rawdata0 = ADC.get_nchan_adc_raw_data(0)
            self.notifyProgress.emit(rawdata0)                   
            time.sleep(0.3)

class TaskThread1(QtCore.QThread):
    notifyProgress = pyqtSignal(int)
   
    def run(self):
        while True:
                      
            rawdata1 = ADC.get_nchan_adc_raw_data(1)
            self.notifyProgress.emit(rawdata1)
            time.sleep(0.3)

class TaskThread2(QtCore.QThread):
    notifyProgress = pyqtSignal(int)
   
    def run(self):
        while True:
            rawdata2 = ADC.get_nchan_adc_raw_data(2)
            self.notifyProgress.emit(rawdata2)
            time.sleep(0.3)

Answer 1

Maybe a Queue could work for you? Link. Queues are FirstInFirstOut so you could have your threads putting stuff in it and then have, I don't know, a fourth thread that will be grabbing stuff from the queue as they come and write them to the file.

Hope this helps.