richard kappler <richkappler <at> gmail.com> writes:
>
> I have a script that reads sensor values gathered by an Arduino board from
serial as a dictionary, said values to later be used in the AI for Nav &
Control. Here's the script:
> #!/usr/bin/python
>
>
> def sensorRead():
> import serial
> from time import sleep
>
> sensors = {}
> sensors = dict.fromkeys('Sonar1 Sonar2 Sonar3 Sonar4 Dewpoint
Temperature Humidity Light'.split())
>
> arduino = serial.Serial('/dev/ttyACM0', 9600)
> sleep(1)
> line = arduino.readline().strip()
> line = line.lstrip('{').rstrip('}').strip()
>
> d = {}
> for item in line.split(','):
> item = item.strip()
> key, value = item.split(':')
> key = key.strip()
>
> value = value.strip()
> d[key]=int(value)
> return d
>
> The script works great with one exception. I understand the problem, I'm
just not sure how to address it. The problem is:
>
> The Arduino runs on a constant loop, it reads each sensor, sends the key
and the value to the serial bus in format for python to read it as a
dictionary, lather, rinse, repeat.
>
> Python querries the bus when told. Usually the python script gets the full
dictionary (all 8 values with keys, brackets etc) but sometimes it doesn't.
Sometimes it only gets the last few values, sometimes it gets nothing or
misses a bracket and throws an error. This makes sense. They are not in sync.
>
> What I need to figure out how to do is have the python script wait until
the next round of values as signified by the opening bracket "{" or check
that it has all 8 values and if not retry or.... something.
>
There should be no sync issue here. The readline method should read from the
serial port until it reaches an EOL character, then return the whole line
(i.e., your sleep(1) should be removed since readline() already waits for
input).
From what you're describing, the real issue seems to be on the side of the
sender. Are you sure, it terminates each line with \n as it should? Where is
that code coming from?
Best,
Wolfgang
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