I’m having trouble to read more than one character using my program, I can’t seem to figure out what went wrong with my program.
import serial ser = serial.Serial( port='COM5', baudrate=9600, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE, bytesize=serial.EIGHTBITS, timeout=0) print("connected to: " + ser.portstr) count=1 while True: for line in ser.read(): print(str(count) + str(': ') + chr(line) ) count = count+1 ser.close()
here are the results I get
connected to: COM5 1: 1 2: 2 3: 4 4: 3 5: 1
actually I was expecting this
connected to: COM5 1:12431 2:12431
something like the above mentioned which is able read multiple characters at the same time not one by one.
I see a couple of issues.
ser.read() is only going to return 1 byte at a time.
If you specify a count
it will read 5 bytes (less if timeout occurrs before 5 bytes arrive.)
If you know that your input is always properly terminated with EOL characters,
better way is to use
That will continue to read characters until an EOL is received.
Even if you get ser.read() or ser.readline() to return multiple bytes,
since you are iterating over the return value, you will
still be handling it one byte at a time.
Get rid of the
for line in ser.read():
and just say:
line = ser.readline()
I use this small method to read Arduino serial monitor with Python
import serial ser = serial.Serial("COM11", 9600) while True: cc=str(ser.readline()) print(cc[2:][:-5])
Serial sends data 8 bits at a time, that translates to 1 byte and 1 byte means 1 character.
You need to implement your own method that can read characters into a buffer until some sentinel is reached. The convention is to send a message like
12431n indicating one line.
So what you need to do is to implement a buffer that will store X number of characters and as soon as you reach that
n, perform your operation on the line and proceed to read the next line into the buffer.
Note you will have to take care of buffer overflow cases i.e. when a line is received that is longer than your buffer etc…
import serial ser = serial.Serial( port='COM5', baudrate=9600, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE, bytesize=serial.EIGHTBITS, timeout=0) print("connected to: " + ser.portstr) #this will store the line line =  while True: for c in ser.read(): line.append(c) if c == 'n': print("Line: " + ''.join(line)) line =  break ser.close()
I was reciving some date from my arduino uno (0-1023 numbers).
Using code from 1337holiday, jwygralak67 and some tips from other sources:
import serial import time ser = serial.Serial( port='COM4', baudrate=9600, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE, bytesize=serial.EIGHTBITS, timeout=0) print("connected to: " + ser.portstr) #this will store the line seq =  count = 1 while True: for c in ser.read(): seq.append(chr(c)) #convert from ANSII joined_seq = ''.join(str(v) for v in seq) #Make a string from array if chr(c) == 'n': print("Line " + str(count) + ': ' + joined_seq) seq =  count += 1 break ser.close()