I am trying to send textual commands to a microcontroller through usb serial port (ttyUSB0), the controller should respond with 'Y' or 'N' and execute the command. Commands are given in the following form '#01a' where the # is beginning symbol 0 is position for A channel and 1 position for B channel and 'a' is checksum of A+B.
I'm stuck and a beginner in python so any help is welcome and appreciated.
p.s. when I connect using putty everything works as expected
also the OS is Ubuntu 16.04 LTS
This is my code:
import time
import serial
import binascii
ser = serial.Serial(
port='/dev/ttyUSB0',
baudrate=19200,
)
print 'Enter your commands below.\r\nInsert "exit" to leave the application.'
AT = chr(int('1000000',2))
A = chr(int('100000',2))
B = chr(int('100000',2))
AB = chr(int('1000000',2))
input = AT + A + B + AB
print input
try:
ser.open()
except Exception, e:
print "error open serial port: " + str(e)
exit()
if ser.isOpen():
try:
ser.flushInput() #flush input buffer, discarding all its contents
ser.flushOutput()#flush output buffer, aborting current output
#and discard all that is in buffer
#write data
ser.write(input)
# print("write data: AT+CSQ")
time.sleep(0.5) #give the serial port sometime to receive the data
numOfLines = 0
while True:
response = ser.readline()
print("read data: " + response)
numOfLines = numOfLines + 1
if (numOfLines >= 5):
ser.close()
except Exception, e1:
print "error communicating...: " + str(e1)
else:
print "cannot open serial port "
Related
Hello I have trouble with read/write from or to device. I wanted to make a serial connection via rs 485 (half-duplex) . When I call read and write functions they didnt receive a data. Anyone know what I do wrong?
def Transmission(ser,data):
if ser.isOpen():
try:
print(data)
ser.flushInput()
ser.flushOutput()
ser.rtscts = True
ser.write(data)
time.sleep(0.1)
numOfLines = 0
print("write: " + data)
while True:
response = ser.readline()
print("read data: " + response)
ser.rtscts = False
numOfLines = numOfLines + 1
if(numOfLines >= 5):
ser.close()
except Exception, e1:
print "error communicating...: " + str(e1)
else:
print "cannot open serial port "
return response
Terminal didnt show receiving data:
powah
write: powah
read data:
read data:
read data:
read data:
read data:
I tried to write with read in the loop (with changing ser.rtscts). How to fix that problem? Thank You
I've been editing this port scanner for an information security project.
The code works but throws errors (Pycharm Edu) on lines 63 and 34 in that order.
The error message for line 63 is: 'line 63, in
checkhost(target). I've looked at this and can't see why this would throw an error specifically as it is defined on line 34.
The error message for line 34 is: 'NameError: global name 'conf' is not defined'. It's not clear why this is a problem either.
Any help is much appreciated.
The Python code environment is Python 2.7.10
#! /usr/bin/python
from logging import getLogger, ERROR # Import Logging Things
getLogger("scapy.runtime").setLevel(ERROR) # Get Rid if IPv6 Warning
import scapy
import sys
from datetime import datetime # Other stuff
from time import strftime
try:
target = raw_input("[*] Enter Target IP Address: ")
min_port = raw_input("[*] Enter Minumum Port Number: ")
max_port = raw_input("[*] Enter Maximum Port Number: ")
try:
if int(min_port) >= 0 and int(max_port) >= 0 and
int(max_port) >= int(min_port): # Test for valid range of ports
pass
else: # If range didn't raise error, but didn't meet criteria
print "\n[!] Invalid Range of Ports"
print "[!] Exiting..."
sys.exit(1)
except Exception: # If input range raises an error
print "\n[!] Invalid Range of Ports"
print "[!] Exiting..."
sys.exit(1)
except KeyboardInterrupt: # In case the user wants to quit
print "\n[*] User Requested Shutdown..."
print "[*] Exiting..."
sys.exit(1)
ports = range(int(min_port), int(max_port)+1)
start_clock = datetime.now() # Start clock for scan time
SYNACK = 0x12 # Set flag values for later reference
RSTACK = 0x14
def checkhost(target): # Function to check if target is up
conf.verb = 0 # Hide output
try:
ping = sr1(IP(dst = ip)/ICMP()) # Ping the target
print "\n[*] Target is Up, Beginning Scan..."
except Exception: # If ping fails
print "\n[!] Couldn't Resolve Target"
print "[!] Exiting..."
sys.exit(1)
def scanport(port): # Function to scan a given port
try:
srcport = RandShort() # Generate Port Number
conf.verb = 0 # Hide output
SYNACKpkt = sr1(IP(dst = target)/TCP(sport = srcport,
dport = port,flags = "S"))
pktflags = SYNACKpkt.getlayer(TCP).flags
if pktflags == SYNACK: # Cross reference Flags
return True # If open, return true
else:
return False
RSTpkt = IP(dst = target)/TCP(sport = srcport, dport = port,
flags = "R") # Construct RST packet send(RSTpkt)
except KeyboardInterrupt: # In case the user needs to quit
RSTpkt = IP(dst = target)/TCP(sport = srcport, dport = port,
flags = "R") send(RSTpkt)
print "\n[*] User Requested Shutdown..."
print "[*] Exiting..."
sys.exit(1)
checkhost(ip) # Run checkhost() function from earlier
print "[*] Scanning Started at " + strftime("%H:%M:%S") + "!\n"
for port in ports: # Iterate through range of ports
status = scanport(port) # Feed each port into scanning function
if status == True: # Test result
print "Port " + str(port) + ": Open" # Print status
stop_clock = datetime.now() # Stop clock for scan time
total_time = stop_clock - start_clock # Calculate scan time
print "\n[*] Scanning Finished!" # Confirm scan stop
print "[*] Total Scan Duration: " + str(total_time) # Print scan time
The problem is with your import statement, it should
be:
>>> import scapy
>>> from scapy.all import conf
>>> conf.verb = 0
or even better to get rid of possible similar errors in the future
just import scapy as:
>>> from scapy.all import *
>>> conf.verb = 0
Now it should work fine.
I got a small python program that communicates with an EV3 robot (lego's robot) via BT. The program sends the EV3 a number 1/2 or 3, the robot makes a predefined movement and send back 'A' to indicate that the movement is done and that it is ready for next command.
The system works great but once in a while the python app crushes with this error message:
'An established connection was aborted by the software in your host machine.' this comes from socket.recv that is called inside btListener() thread.
The relevant python parts:
import bluetooth
from gmail import *
import re
from gtts import gTTS
from time import sleep
import pygame
import serial
import thread
import os
import ftplib
from StringIO import StringIO
from blynkapi import Blynk
def a(): #Send 'a' to 'Status' mailbox
print "Send a to robot"
for i in commandA:
client_sock.send(chr(i))
sleep(1)
def b(): # Send 'b' to 'Status' mailbox
def c(): # Send 'c' to 'Status' mailbox
def clear(): # Send clear array to 'Status' mailbox
for i in clearArray:
client_sock.send(chr(i))
def btListener():
# Listen for end of run reply from the EV3
global ev3Flag, listenFlag
while True:
if listenFlag and (not ev3Flag):
try:
data = client_sock.recv(1024) #Check if EV3 is ready for new command
if data[-2] == 'A':
ev3Flag = True
print "Received 'Ready' from EV3 "
sleep(1)
except Exception as e:
print(e)
print "Failed to read data from socket"
def queueHandler():
# Read next command from QueueArray, call sendFunc and clear the queue
global ev3Flag, listenFlag, queueArray
while True:
if len(queueArray) > 0 and ev3Flag:
sendFunc(queueArray[0])
queueArray.pop(0)
def sendFunc(cmd):
#Send the next command on QueueArray to the EV3
global ev3Flag, listenFlag
if cmd == 1:
try:
ev3Flag = False
listenFlag = False
a()
listenFlag = True
sleep(3)
clear() # clear the EV3 btsocket with a default message
except Exception as e:
print "Error on sendFunc cmd = 1"
print(e)
elif cmd == 2:
try:
except Exception as e:
elif cmd == 3:
try:
except Exception as e:
if __name__ == "__main__":
# Blynk setup
blynk = Blynk(auth_token)
switch1 = Blynk(auth_token, pin = "V0")
switch2 = Blynk(auth_token, pin = "V1")
switch3 = Blynk(auth_token, pin = "V2")
print "Blynk connected"
queueArray = [] # Queue array to hold incoming commands
listenFlag = True # Listen to message from EV3
ev3Flag = True # EV3 ready for new command flag
# BT CONNECTION WITH EV3 #
print "Searching for BT connections: "
nearby_devices = bluetooth.discover_devices()
for bdaddr in nearby_devices:
print bdaddr + " - " + bluetooth.lookup_name(bdaddr)
if target_name == bluetooth.lookup_name(bdaddr):
target_address = bdaddr
break
server_sock = bluetooth.BluetoothSocket(bluetooth.RFCOMM)
port = 1
server_sock.bind(("", port))
server_sock.listen(1)
client_sock, address = server_sock.accept()
print "Accepted connection from ", address
if target_address is not None:
print "found target bluetooth device with address ", target_address
else:
print "could not find target bluetooth device nearby"
# END BT CONNECTION WITH EV3 #
try:
thread.start_new_thread(queueHandler, ())
except Exception as e: print(e)
try:
thread.start_new_thread(btListener, ())
except Exception as e: print(e)
while True:
res1 = switch1.get_val()
res2 = switch2.get_val()
res3 = switch3.get_val()
if (int)(res1[0]) == 1:
print "Add 1 to queue"
queueArray.append(1)
if (int)(res2[0]) == 1:
print "Add 2 to queue"
queueArray.append(2)
if (int)(res3[0]) == 1:
print "Add 3 to queue"
queueArray.append(3)
Edit 1:
I tested it a bit more and it seems that the crush happens when the program tries to recv data and send data the same time. (via the clear() or a()/b()/c() functions), could that be the situation?
I'm new to sockets so the first solution that comes in mind is create a flag to limit the action of the socket, is there a better/smarter way to keep that from happening?
Edit 2:
I moved the 'listenFlag = True' line inside sendFunc() to after my call to clear() and it seems to solve the problem which was probably due to the python program trying to receive and sand at the same time.
I moved the 'listenFlag = True' line inside sendFunc() to after my call to clear() and it seems to solve the problem which was probably due to the python program trying to receive and sand at the same time.
Reading data from the serial port:
readline() in the below code return the null vector, the reading data from the serial port is hexadecimal number like AABB00EF the putty gives me the output means the communication is working but nothing works via python
here is the code:
#!/usr/bin/python
import serial, time
ser = serial.Serial()
ser.port = "/dev/ttyUSB0"
ser.baudrate = 115200
#ser.bytesize = serial.EIGHTBITS
#ser.parity = serial.PARITY_NONE
#ser.stopbits = serial.STOPBITS_ONE
#ser.timeout = None
ser.timeout = 1
#ser.xonxoff = False
#ser.rtscts = False
#ser.dsrdtr = False
#ser.writeTimeout = 2
try:
ser.open()
except Exception, e:
print "error open serial port: " + str(e)
exit()
if ser.isOpen():
try:
#ser.flushInput()
#ser.flushOutput()
#time.sleep(0.5)
# numOfLines = 0
# f=open('signature.txt','w+')
while True:
response = ser.readline()
print len(response)
#f=ser.write(response)
print response
# numOfLines = numOfLines + 1
f.close()
ser.close()
except Exception, e1:
print "error communicating...: " + str(e1)
else:
print "cannot open serial port "
readline will try to read until the end of the line is reached, if there is no \r or \n then it will wait forever (if you have a timeout it might work...) instead try something like this
ser.setTimeout(1)
result = ser.read(1000) # read 1000 characters or until our timeout occures, whichever comes first
print repr(result)
just use this code
ser = serial.Serial("/dev/ttyUSB0",115200,timeout=1)
print "OK OPENED SERIAL:",ser
time.sleep(1)# if this is arduino ... wait longer time.sleep(5)
ser.write("\r") # send newline
time.sleep(0.1)
print "READ:",repr(ser.read(8))
you can create a readuntil method
def read_until(ser,terminator="\n"):
resp = ""
while not resp.endswith(terminator):
tmp = ser.read(1)
if not tmp: return resp # timeout occured
resp += tmp
return resp
then just use it like
read_until(ser,"\r")
I have raspberry PI B+ with connected Telegesis ZigBee module(ETRX3 USB sticks) via USB. Using commands:
debian:~# stty -F /dev/ttyUSB0 -raw ispeed 19200 ospeed 19200
debian:~# cat < /dev/ttyUSB0 &
debian:~# echo "ATI" > /dev/ttyUSB0
the ZigBee module executed ATI command and I can see the correct output:
Telegesis ETRX357
R308C
OK
The same thing I want to do with python script. I was written python script with code:
#!/usr/bin/env python
# based on tutorials:
# http://www.roman10.net/serial-port-communication-in-python/
# http://www.brettdangerfield.com/post/raspberrypi_tempature_monitor_project/
import serial, time
SERIALPORT = "/dev/ttyUSB0"
BAUDRATE = 19200
ser = serial.Serial(SERIALPORT, BAUDRATE)
ser.bytesize = serial.EIGHTBITS #number of bits per bytes
ser.parity = serial.PARITY_NONE #set parity check: no parity
ser.stopbits = serial.STOPBITS_ONE #number of stop bits
#ser.timeout = None #block read
#ser.timeout = 0 #non-block read
ser.timeout = 2 #timeout block read
ser.xonxoff = False #disable software flow control
ser.rtscts = False #disable hardware (RTS/CTS) flow control
ser.dsrdtr = False #disable hardware (DSR/DTR) flow control
ser.writeTimeout = 0 #timeout for write
print 'Starting Up Serial Monitor'
try:
ser.open()
except Exception, e:
print "error open serial port: " + str(e)
exit()
if ser.isOpen():
try:
ser.flushInput() #flush input buffer, discarding all its contents
ser.flushOutput()#flush output buffer, aborting current output
ser.write("ATI")
print("write data: ATI")
time.sleep(0.5)
numberOfLine = 0
while True:
response = ser.readline()
print("read data: " + response)
numberOfLine = numberOfLine + 1
if (numberOfLine >= 5):
break
ser.close()
except Exception, e:
print "error communicating...: " + str(e)
else:
print "cannot open serial port "
and get results as on the screen
ATI
but I want to command be execute by ZigBee module, as like in shell commands. What am I doing wrong?
you need to append an end-of-line to your write()
ser.write("ATI\r\n")
you should change the timeout to:
ser.timeout = None
Otherwise readline() will return after 2 seconds, even if nothing has been read.