Question

I have a stupid python problem.

I’m trying to read a line from a file everytime i get a ‘READY’ message from a serial connection so i wrote this :

import serial
from time import sleep

port = "/dev/tty.usbserial-A400fYTT"
speed = 57600
polarfile = 'polarfile.pg'

f = open(polarfile, 'r')

ser = serial.Serial(port, speed, timeout=0)

while True:
    data = ser.read(9999)
    if len(data) > 0:
        if(data == 'READY'):
            f.readline()
        else:
            sleep(0.5)

    sleep(1)

ser.close()

But it doesn’t work, however if i replace the if(data == ‘READY’ block by print data. I get the READY message.

Also i can read my file with f.readline()…

Thanks to give advice to a py newbie

—
edit :
Important info, the serial doesn’t receive only “READY” message, but a bunch of other, but i want just to react when the “READY” messsage is received.

Answer 1

I just replace

data = ser.read(9999)

by

data = ser.readline(9999) which gives me the message line by line instead of second by second of input data and then replace

if( data == 'READY' ):by

if (data.startswith('READY')):

and now it works 🙂