import serial
from time import sleep

with serial.Serial('/dev/ttyUSB0', 9600, timeout=1) as ser:
    ser.write(b'a')
    while True:
        x = ser.read()          # read one byte
        if x != b'':
            pass
        print(x.decode('utf'))
        #ser.write(b'a')
        #print(ser.read())
        sleep(1)