Python serial read

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March 11th, 2013, 03:09 AM

ajit.nayak87

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Python serial read

Dear all,

I am using python 2.5 and pyserial 2.5
i wanna help in writing simple code in python where i wanna separate string

i am getting string in this format
---------
time and date:11/3/2013 11:10:5
dir:fwd
actual position : 30
desire position :28
---------

i wanna write this in to excel sheet for every 10 min such away that in column c1:time and date c2: dir, c3: actual position c4: desire position

in row i could able to write time,dir,AP,DP one after the other

i have written below code to write in to text file

Code:

import serial
import csv
import os
import time


def main():
    pass

if __name__ == '__main__':
    main()
    COUNT=0
    while(COUNT<=60):
      ser=serial.Serial()
      ser.port=12
      ser.baudrate=9600
      ser.open()
      x=ser.read(150)
      foo=open("time.txt","a+");
      print x
      foo.write(x)
      foo.write("\n")
      foo.close();
      ser.close()
      time.sleep(60)
      COUNT=COUNT+1

      if(COUNT==60):
        COUNT=0

March 11th, 2013, 03:19 AM

partoj

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Please use code tags when pasting your code, otherwise it's impossble to read it.

Use split() to extract the values you want to get:

Code:

>>> str = "time and date: 2013/03/11 09:22"
>>> val = str.split(":")
>>> val
['time and date', ' 2013/03/11 09', '22']
>>> time_and_date = ":".join(val[1:])

March 11th, 2013, 03:37 AM

ajit.nayak87

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How to get the serial data ??
when i say ser.read(100) i am getting those data.
how to write in to excel sheet.???

Quote:

Originally Posted by partoj

Please use code tags when pasting your code, otherwise it's impossble to read it.

Use split() to extract the values you want to get:

Code:

>>> str = "time and date: 2013/03/11 09:22"
>>> val = str.split(":")
>>> val
['time and date', ' 2013/03/11 09', '22']
>>> time_and_date = ":".join(val[1:])

March 11th, 2013, 03:59 AM

ajit.nayak87

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output window:

value is ['calc dir', ' in FWD\r\nActuator On/OFF', '0\r\nMode', '1\r\nLocal Date & Time', '11/3/2013 14', '23', '21\r\nDesired Angle', '-15.32\r\n Actual Pos', '-10.40\r\n----------']
date is in FWD
Actuator On/OFF:0
Mode:1
Local Date & Time:11/3/2013 14:23:21
Desired Angle:-15.32
Actual Pos:-10.40

what are changes need to made in below code

code modified :

Code:


import serial
import csv
import os
import time


def main():
    pass

if __name__ == '__main__':
    main()
    COUNT=0
    while(COUNT<5):
      ser=serial.Serial()
      ser.port=12
      ser.baudrate=9600
      ser.open()
      str=ser.read(150)
      val=str.split(":")
      print "value is",val
      time_date=":".join(val[1:])
      print "date is ",time_date
      foo=open("time.txt","a+");
      print str
      foo.write(str)
      foo.write("\n")
      foo.close();
      ser.close()
      COUNT=COUNT+1

Quote:

Originally Posted by ajit.nayak87

How to get the serial data ??
when i say ser.read(100) i am getting those data.
how to write in to excel sheet.???

March 11th, 2013, 04:23 AM

partoj

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I've modified your example a little, hope that is ok. I've also had to comment out the serial stuff, but if you uncomment those lines and remove my "str =" line it should work.

Code:

from __future__ import with_statement
import serial

if __name__ == '__main__':
    for _ in range(0, 5):
#        ser=serial.Serial()
#        ser.port=12
#        ser.baudrate=9600
#        ser.open()
#        str=ser.read(150)
#        ser.close()
        str = 'calc dir: in FWD\r\nActuator On/OFF:0\r\nMode:1\r\nLocal Date & Time:11/3/2013 14:23:21\r\nDesired Angle:-15.32\r\n Actual Pos:-10.40\r\n----------'
        lines = str.split("\r\n")   # First get each line
        with open("time.txt", "a+") as f:   # the 'with' statement also closes the file
            for line in lines[:-1]:    # Ignore the last line with only hyphens
                parts = line.split(":")
                f.write("%s," % ":".join(parts[1:]))
            f.write("\n")

March 11th, 2013, 04:39 AM

ajit.nayak87

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What does F indicate in line of code

Quote:

Originally Posted by partoj

I've modified your example a little, hope that is ok. I've also had to comment out the serial stuff, but if you uncomment those lines and remove my "str =" line it should work.

Code:

from __future__ import with_statement
import serial

if __name__ == '__main__':
    for _ in range(0, 5):
#        ser=serial.Serial()
#        ser.port=12
#        ser.baudrate=9600
#        ser.open()
#        str=ser.read(150)
#        ser.close()
        str = 'calc dir: in FWD\r\nActuator On/OFF:0\r\nMode:1\r\nLocal Date & Time:11/3/2013 14:23:21\r\nDesired Angle:-15.32\r\n Actual Pos:-10.40\r\n----------'
        lines = str.split("\r\n")   # First get each line
        with open("time.txt", "a+") as f:   # the 'with' statement also closes the file
            for line in lines[:-1]:    # Ignore the last line with only hyphens
                parts = line.split(":")
                f.write("%s," % ":".join(parts[1:]))
            f.write("\n")

March 11th, 2013, 04:45 AM

partoj

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Quote:

Originally Posted by ajit.nayak87

What does F indicate in line of code

f is the file object used to write to "time.txt".

March 11th, 2013, 04:47 AM

ajit.nayak87

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i have tried above code. But it is not writing whole data into parts
it will write up to time and date , missing desired and actual angle from part. how to get entire line of data then seprating out.
Any specific instrction to check EOF

Quote:

Originally Posted by ajit.nayak87

What does F indicate in line of code

March 11th, 2013, 04:54 AM

ajit.nayak87

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output after modification of code

[' in FWD']
['0']
['1']
['11/3/2013 15', '16', '50']

Quote:

Originally Posted by ajit.nayak87

What does F indicate in line of code

#10

March 11th, 2013, 04:56 AM

partoj

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Do you nean after my modification of the code, or yours? If the latter, please post your updated code.

#11

March 11th, 2013, 04:57 AM

ajit.nayak87

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Code:

import serial
import csv
import os
import time


def main():
    pass

if __name__ == '__main__':
    main()
    COUNT=0
    while(COUNT<=2):
      ser=serial.Serial()
      ser.port=12
      ser.baudrate=9600
      ser.open()
      str=ser.read(100)
     # val=str.split(":")
     # print "value is",val

      lines=str.split("\r\n")
      for lines in lines[:-1]:
            parts=lines.split(":")
            foo=open("new.txt","a+");
            foo.write("%s," % ":".join(parts[1:]))

            print parts[1:]
            foo.write("\n")
            foo.close()

      """calc_dir=":".join(val[1:])
      print "calc_dir:",calc_dir

      act_on_off=":".join(val[1:])
      print "act_on:",act_on_off

      mode=":".join(val[1:])
      print "mode:",mode

      date_time=":".join(val[1:])
      print "date_time:",date_time

      desire_angle=":".join(val[1:])
      print "desired_angle:",desire_angle

      actual_angle=":".join(val[1:])
      print "actual_angle:",actual_angle
"""


      foo=open("time.txt","a+");
     # print str
      #foo.write(str)
      foo.write("\n")
      foo.close();
      ser.close()
      COUNT=COUNT+1

QUOTE=partoj]Do you nean after my modification of the code, or yours? If the latter, please post your updated code.[/QUOTE]

#12

March 11th, 2013, 05:11 AM

partoj

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You changed the code to only read 100 bytes, earlier you read 150 bytes.

Code:

str=ser.read(100)

#13

March 11th, 2013, 05:16 AM

ajit.nayak87

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Code:

import serial
import csv
import os
import time


def main():
    pass

if __name__ == '__main__':
    main()
    COUNT=0
    while(COUNT<=2):
      ser=serial.Serial()
      ser.port=12
      ser.baudrate=9600
      ser.open()
      str=ser.read(150)
      val=str.split(":")
      print "value is",val
      lines=str.split("\r\n")
      ser.close()
      COUNT=COUNT+1
    for lines in lines[:-1]:
            parts=lines.split(":")
            foo=open("new.txt","a+");
            foo.write("%s," % ":".join(parts[1:]))
            print parts[1:]
            foo.write("\n")
            foo.close()

Modified the code and it started working fine. Now i just wanted to know i put those data in excel sheet under specified column
like DIR,timeand date, desire angle, actual angle.

it some how look like
1)
dir-timeand date-desireangle- actual angle
fwd-23-3-13 3:4:50-30 -28

2) how to give delay in program . suppose i wanna write it for every 10 min how can give delay

#14

March 11th, 2013, 07:47 AM

partoj

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Quote:

Originally Posted by ajit.nayak87

Excel can read csv files, so I suggest you simply output your data as comma-separated values. Make the first line a header with the column names you want to have.

Quote:

2) how to give delay in program . suppose i wanna write it for every 10 min how can give delay

Either use time.sleep(), or (imho better) run a cron script every 10 minutes that will run your script.