[OpenTRV-dev] python opentrv to emoncms script...

[Bo Herrmannsen]

could it be that the data is not json but just looks like it?

2015-10-06 22:00 GMT+02:00 Bo Herrmannsen <bo.herrmannsen at gmail.com>:

> now the script is:
>
> import sys
> import serial
> import json
>
> port = "/dev/ttyUSB0"
> baud = 4800
>
> ser = serial.Serial()
> ser.port = port
> ser.baudrate = baud
>
> try:
>    ser.open()
> except:
>    sys.stderr.write("Error opening serial port %s\n" % (ser.portstr) )
>    sys.exit(1)
>
> ser.setRtsCts(0)
>
> while 1:
>    # Read from serial port, blocking
>    data = ser.read(1)
>
>    # If there is more than 1 byte, read the rest
>    n = ser.inWaiting()
>    if n:
>        data = data + ser.read(n)
>
>
>
>    sys.stdout.write(data)
>
>    if data.startswith('{'):
>
>     j = json.loads(data)
>     print j['@']
>
>
>
> my logic is to print what comes in from serial and that part works fine
>
> i then want to build on it and if we have a json string then write just
> the units id...
>
> the last part is failing me.. i get:
>
>
> {"@":"151f","+":4,"T|C16":336,"O":1,"vac|h":94,"v|%":0}
> {Traceback (most recent call last):
>   File "opentrvimport.py", line 35, in <module>
>     j = json.loads(data)
>   File "/usr/lib/python2.7/json/__init__.py", line 326, in loads
>     return _default_decoder.decode(s)
>   File "/usr/lib/python2.7/json/decoder.py", line 365, in decode
>     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
>   File "/usr/lib/python2.7/json/decoder.py", line 381, in raw_decode
>     obj, end = self.scan_once(s, idx)
> ValueError: Expecting object: line 1 column 0 (char 0)
>
>
> 2015-10-06 17:05 GMT+02:00 Bo Herrmannsen <bo.herrmannsen at gmail.com>:
>
>> Hi
>>
>> I started on a script that can read serial data from a rev2 unit and send
>> the data on to emoncms.
>>
>> i get this on the serial line
>>
>> {"@":"2800","+":4,"T|C16":544,"vC|%":2340,"O":1}
>>
>>
>> and so far i have this python script
>>
>>
>> import serial
>> import io
>> import time
>> ser = serial.Serial('/dev/ttyUSB0',4800)
>>
>>
>> sio = io.TextIOWrapper(io.BufferedRWPair(ser, ser, 1),
>> encoding='ascii',newline='\r\n')
>>
>> while ser.isOpen():
>>
>>           datastring = sio.readline()
>>
>> print datastring
>>
>>
>>
>>
>> the serial data end with CRLF
>>
>> but it does not print anything.... where am i wrong?
>>
>> before i used this script:
>>
>> import serial
>> import time
>> s = serial.Serial('/dev/ttyUSB0',4800)
>>
>> while 1:
>>    if s.inWaiting():
>>       val = s.read(s.inWaiting())
>>       print val
>>
>> but then i got:
>>
>> {"@":"0950","
>> +":
>> 5,"
>> t
>> T|C
>> ":
>> 1
>> 9,"
>> vC|%
>> ":
>> 20
>> 0,"
>> T|
>> C
>> 1
>> 6":
>> 33
>> 1}
>>
>>
>>
>>
>
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