Reading python serial data without new line - python
I am reading serial port data in python. The data does not have newline, so I am receiving data continuously. The data packet has a termination with '|'. I want to read data continuously and print it on newline after '|'
My current data looks like this (highlighted fields are data of my interest in each packet, how shall I extract it and plot )
b'\x01\x063\x011;790.10,3.73,203.45;0.00;28|1;503.36,2.88,129.87;2.00;28|1;1.00,1.60,0.23;4.00;28|1;167.10,1.13,44.98;6.00;28|1;0.07,0.34,2.02;8.00;28|1;100.44,1.04,26.24;10.00;28|1;0.33,0.89,1.65;12.00;28|1;71.72,0.13,19.10;14.00;28|1;0.07,0.41,1.76;16.00;28|1;55.70,0.08,14.89;18.00;28|1;0.19,0.61,2.07;20.00;28|1;45.84,0.46,11.70;22.00;28|1;0.07,0.44,1.76;24.00;28|1;38.87,0.53,9.90;26.00;28|1;0.12,0.11,1.62;28.00;28|1;33.65,0.26,8.57;30.00;28|1;0.07,0.11,1.58;32.00;28|1;29.80,0.36,7.51;34.00;28|1;0.09,0.37,1.48;36.00;28|1;26.65,0.17,6.80;38.00;28|1;0.07,0.28,1.43;40.00;28|1;24.07,0.11,6.32;42.00;28|1;0.06,0.14,1.66;44.00;28|1;22.11,0.09,5.65;46.00;28|1;0.07,0.15,1.66;48.00;28|1;20.41,0.22,5.13;50.00;28|1;0.05,0.08,1.61;52.00;28|1;18.93,0.05,4.80;54.00;28|1;0.06,0.12,1.77;56.00;28|1;17.74,0.14,4.24;58.00;28|1;0.03,0.04,1.57;60.00;28|1;16.61,0.06,4.03;62.00;28|1;0.06,0.07,1.55;64.00;28|1;15.59,0.14,3.86;66.00;28|1;0.02,0.11,1.68;68.00;28|1;14.78,0.12,3.49;70.00;28|1;0.06,0.18,1.57;72.00;28|1;14.03,0.05,3.39;74.00;28|1;0.01,0.09,1.67;76.00;28|1;13.35,0.04,3.15;78.00;28|1;0.05,0.14,1.72;80.00;28|1;12.81,0.18,2.85;82.00;28|1;0.00,0.10,1.60;84.00;28|1;12.26,0.16,2.75;86.00;28|1;0.05,0.07,1.61;88.00;28|1;11.73,0.08,2.58;90.00;28|1;0.01,0.08,1.58;92.00;28|1;11.31,0.10,2.46;94.00;28|1;0.04,0.16,1.54;96.00;28|1;10.87,0.07,2.40;98.00;28|1;0.01,0.08,1.57;100.00;28|1;10.48,0.06,2.32;102.00;28|1;0.04,0.06,1.66;104.00;28|1;10.19,0.06,2.15;106.00;28|1;0.02,0.03,1.64;108.00;28|1;9.87,0.09,2.05;110.00;28|1;0.03,0.07,1.65;112.00;28|1;9.57,0.02,1.94;114.00;28|1;0.02,0.04,1.69;116.00;28|1;9.33,0.09,1.75;118.00;28|1;0.03,0.04,1.57;120.00;28|1;9.05,0.03,1.75;122.00;28|1;0.02,0.02,1.61;124.00;28|1;8.79,0.08,1.68;126.00;28|1;0.02,0.10,1.65;128.00;28|1;8.61,0.05,1.55;130.00;28|1;0.03,0.11,1.58;132.00;28|1;8.40,0.06,1.56;134.00;28|1;0.02,0.04,1.67;136.00;28|1;8.22,0.05,1.42;138.00;28|1;0.03,0.07,1.65;140.00;28|1;8.08,0.13,1.31;142.00;28|1;0.01,0.07,1.59;144.00;28|1;7.90,0.08,1.30;146.00;28|1;0.03,0.06,1.62;148.00;28|1;7.73,0.03,1.20;150.00;28|1;0.01,0.07,1.58;152.00;28|1;7.60,0.04,1.17;154.00;28|1;0.03,0.10,1.57;156.00;28|1;7.45,0.07,1.16;158.00;28|1;0.01,0.02,1.62;160.00;28|1;7.33,0.04,1.10;162.00;28|1;0.03,0.04,1.65;164.00;28|1;7.26,0.05,1.01;166.00;28|1;0.00,0.01,1.64;168.00;28|1;7.14,0.04,0.96;170.00;28|1;0.03,0.05,1.66;172.00;28|1;7.03,0.05,0.88;174.00;28|1;0.00,0.02,1.65;176.00;28|1;6.95,0.07,0.78;178.00;28|1;0.03,0.05,1.57;180.00;28|1;6.84,0.02,0.81;182.00;28|1;0.01,0.03,1.62;184.00;28|1;6.75,0.04,0.74;186.00;28|1;0.03,0.09,1.62;188.00;28|1;6.71,0.06,0.68;190.00;28|1;0.01,0.07,1.59;192.00;28|1;6.64,0.06,0.70;194.00;28|1;0.02,0.02,1.67;196.00;28|1;6.58,0.06,0.57;198.00;28|1;0.01,0.04,1.62;200.00;28|1;6.54,0.10,0.53;202.00;28|1;0.02,0.08,1.59;204.00;28|1;6.46,0.04,0.52;206.00;28|1;0.02,0.06,1.62;208.00;28|1;6.40,0.01,0.45;210.00;28|1;0.02,0.06,1.58;212.00;28|1;6.37,0.03,0.45;214.00;28|1;0.02,0.06,1.60;216.00;28|1;6.32,0.07,0.43;218.00;28|1;0.02,0.01,1.64;220.00;28|1;6.29,0.02,0.36;222.00;28|1;0.02,0.03,1.65;224.00;28|1;6.29,0.05,0.31;226.00;28|1;0.01,0.02,1.64;228.00;28|1;6.24,0.01,0.26;230.00;28|1;0.02,0.04,1.66;232.00;28|1;6.21,0.06,0.18;234.00;28|1;0.01,0.03,1.62;236.00;28|1;6.20,0.05,0.14;238.00;28|1;0.02,0.06,1.57;240.00;28|1;6.16,0.01,0.16;242.00;28|1;0.01,0.04,1.62;244.00;28|1;6.16,0.02,0.09;246.00;28|1;0.02,0.09,1.60;248.00;28|1;6.18,0.07,0.09;250.00;28|1;0.00,0.04,1.60;252.00;28|1;6.17,0.06,0.08;254.00;28|DATAEND|
I am currenlty reading 3480 bytes. but want to read data continuously
import serial
ser = serial.Serial('/dev/ttyUSB0', 115200, serial.EIGHTBITS, serial.PARITY_NONE, serial.STOPBITS_ONE)
buff = list()
values = bytearray([1,6,51,1]) # serial port command to read serial data
#print(type(values))
ser.write(values)
while True:
s = ser.read(3480)
print(s)
I want to separate all fields and print the data that is highlighted
I would recommend the use of read_until which allows you to define the character which works like a newline (LF is the default value). The call signature is read_until(expected=LF, size=None). For details consult https://pyserial.readthedocs.io/en/latest/pyserial_api.html . Alternatively you could read everything which is available and use a regular expression to find the single packages and extract the fields. This can be done by re.find_iter.
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Python - Reading Serial Data that is constantly sending for parsing
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Since you are getting another lot of data every 50mS, you need to be able to sync with the start of the data: buffer = b'' header = b'\0x98' while True: if port.in_waiting: buffer += port.read(port.in_waiting) while len(buffer) >= 2: if buffer[0] == header and buffer[1] == header: break buffer=buffer[1:] if len(buffer) >= 13: print(buffer[:13]) # or otherwise process latest buffer buffer = buffer[13:] This code starts with an empty buffer and then reads whatever data arrives at the serial port. While the buffer does not start with the two header bytes, any excess at the front is discarded. Once the buffer starts with the right header and is long enough, the 13 bytes are printed here (but you might want to call another function to process a whole packet), and then that packet is thrown away, ready to start with whatever arrives next.
Python Socket is receiving inconsistent messages from Server
So I am very new to networking and I was using the Python Socket library to connect to a server that is transmitting a stream of location data. Here is the code used. import socket BUFFER_SIZE = 1024 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((gump.gatech.edu, 756)) try: while (1): data = s.recv(BUFFER_SIZE).decode('utf-8') print(data) except KeyboardInterrupt: s.close() The issue is that the data arrives in inconsistent forms. Most of the times it arrives in the correct form like this: 2016-01-21 22:40:07,441,-84.404153,33.778685,5,3 Yet other times it can arrive split up into two lines like so: 2016-01-21 22:40:07,404,-84.396004,33.778085,0,0 The interesting thing is that when I establish a raw connection to the server using Putty I only get the correct form and never the split. So I imagine that there must be something happening that is splitting the message. Or something Putty is doing to always assemble it correctly. What I need is for the variable data to contain the proper line always. Any idea how to accomplish this?
It is best to think of a socket as a continuous stream of data, that may arrive in dribs and drabs, or a flood. In particular, it is the receivers job to break the data up into the "records" that it should consist of, the socket does not magically know how to do this for you. Here the records are lines, so you must read the data and split into lines yourself. You cannot guarantee that a single recv will be a single full line. It could be: just part of a line; or several lines; or, most probably, several lines and another part line. Try something like: (untested) # we'll use this to collate partial data data = "" while 1: # receive the next batch of data data += s.recv(BUFFER_SIZE).decode('utf-8') # split the data into lines lines = data.splitlines(keepends=True) # the last of these may be a part line full_lines, last_line = lines[:-1], lines[-1] # print (or do something else!) with the full lines for l in full_lines: print(l, end="") # was the last line received a full line, or just half a line? if last_line.endswith("\n"): # print it (or do something else!) print(last_line, end="") # and reset our partial data to nothing data = "" else: # reset our partial data to this part line data = last_line
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Edit: socket.recv() is blocking and like the others said, you wont get an exact line each time you call the method. So as a result, the socket is waiting for data, gets what it can get and then returns. When you print this, because of pythons default end argument, you may get more newlines than you expected. So to get the raw stuff from your server, use this: import socket BUFFER_SIZE = 1024 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(('gump.gatech.edu', 756)) try: while (1): data=s.recv(BUFFER_SIZE).decode('utf-8') if not data: break print(data, end="") except KeyboardInterrupt: s.close()
Converting data from serial/usb using PySerial
I have a UBlox receiver connected to my computer and I am trying to read it using PySerial however I am new to python and was hoping to get some clarification/help on understanding the data. My code looks like: import serial # open the connection port connection = serial.Serial('/dev/ttyACM0', 9600) # open a file to print the data. I am doing this to make # sure it is working file1 = open('output_file', 'wb+') # All messages from ublox receivers end with a carriage return # and a newline msg = connection.readline() # print the message to the file print >> file1, msg What I get in the file, and when I print the 'type' of msg it is a list: ['\xb5b\x01\x064\x00\xe0\x88\x96#\xd3\xb9\xff\xffX\x07\x03\xdd6\xc31\xf6\xfd)\x18\xea\xe6\x8fd\x1d\x00\x01\x00\x00\x00\x00\x00\x00\xfd\xff\xff\xff\x01\x00\x00\x00\x02\x00\x00\x00p\x00\x02\x0f\x16\xa2\x02\x00\x9c\xeb\xb5b\x01\x07\\x00\xe0\x88\x96#\xe0\x07\x01\x17\x15237\x04\x00\x00\x00\xd6\xb9\xff\xff\x03\x01\n'] ["\x1a\x0c\x04\x19'y\x00$\xf7\xff\xff\x1a\x1d\x04\x01\x00\x007\x00\x00\x00\x00\x00\x02\x1f\x0c\x01\x00+:\x00\x00\x00\x00\x00\x01 \r\x07&-\x9f\x00\xff\x01\x00\x00\x17\xc1\x0c\x04\x16\n"] In order to interpret/decode the ublox messages have two format types. Some of the messages are in NMEA format(basically comma delimited) $MSG, 1, 2, 3, 4 Where the other messages are straight hexidecimal, where each byte or set of bytes represent some information [AA BB CC DD EE] So my question is: is there a way I can interpret/convert the data from serial connection to a readable or more usable format so I can actually work with the messages. Like I said, I am new to python and more used to C++ style strings or array of characters `
A typical parsing task. In this case, it'll probably be the simplest to make tokenization two-stage: read the data until you run into a message boundary (you didn't give enough info on how to recognize it) split the read message into its meaningful parts for type 1, it's likely re.split(", *",text) for type 2, none needed display the parts however you want Regarding why serial.Serial.readline returns a list. I consulted the sources - serial.Serial delegates readline to io.IOBase, and its source indeed shows that it should return a bytestring. So, the function might be overridden in your code by something. E.g. what do print connection.readline and print serial.Serial.readline show?
reading from sys.stdin without newline or EOF
I want to recieve data from my gps-tracker. It sends data by tcp, so I use xinetd to listen some tcp port and python script to handle data. This is xinetd config: service gps-gprs { disable = no flags = REUSE socket_type = stream protocol = tcp port = 57003 user = root wait = no server = /path/to/gps.py server_args = 3 } Config in /etc/services gps-gprs 57003/tcp # Tracking system And Python script gps.py #!/usr/bin/python import sys def main(): data = sys.stdin.readline().strip() #do something with data print 'ok' if __name__ =='__main__': main() The tracker sends data strings in raw text like $GPRMC,132017.000,A,8251.5039,N,01040.0065,E,0.00,,010111,0,,A*75+79161234567# The problem is that sys.stdin in python script doesn't recieve end of line or end of file character and sys.stdin.readline() goes forever. I tried to send data from another pc with a python script import socket s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(('', 57003)) s.sendall( u'hello' ) data = s.recv(4024) s.close() print 'Received', data and if the message is 'hello', it fails, but if the message is 'hello\n', it's ok and everything is fine. But I don't know ho to tell tracker or xinetd to add this '\n' at the end of messages. How can I read the data from sys.stdin without EOF or EOL in it?
Simple: data=sys.stdin.read().splitlines() for i in data: print i No newlines
sys.stdin.readline() waits forever until it receives a newline. Then it considers the current line to be complete and returns it in full. If you want to read data that doesn't contain newlines or you don't want to wait until a newline is received before you process (some of) the data, then you're going to have to use something other than readline. Most likely you should call read, which reads arbitrary data up to a given size. However, your GPS appears to be sending data in the well-known NEMA format, and that format certainly terminates each line with a newline. Actually, it probably terminates each line with CRLF (\r\n) but it is possible that the \r could be getting munged somewhere before it gets to your TCP socket. Either way there's a \n at the very end of each line. If your readline call is hanging without returning any lines, most likely it's because the sender is buffering lines until it has a full buffer. If you waited long enough for the sender's buffer to fill up, you'd get a whole bunch of lines at once. If that's what's happening, you'll have to change the sender to that it flushes its send buffer after each NEMA sentence.
It seems you are receiving # instead of <CR><LF>, just read until the # sign. data = "" while len(data) == 0 or data[-1] <> '#': data += sys.stdin.read(1) #do something with data print 'ok'
My solution : var = sys.stdin.readline().replace('\n', '') It : find the newline in the entry, replace it from the entry by '' (none) ~remove, assigne it to variable.
Python - Fetching data from two serial ports in realtime
My project is a directional antenna which is mounted on a self-stabilizing base. The language I wish to use is python, but changing this to a more suited language, is a possibility, if needed. Problem 1: How would you go about taking in serial data in real-time[1], and then parse the data in python? Problem 2: How can I then send the output of the program to servos, which are mounted on the base? (feedback system). [1](Fastest possible time for data transfer, processing and then output)
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