Python, Raspberry, and Arduino Communication

Question

I have been working with my Raspberry, Arduino and applying some Python to make them communicate. I also installed pyserial. If I use IDLE and try the following I get my expected results.

  >>> import serial
  >>> ser = serial.Serial('/dev/ttyUSB0',115200)
  >>> ser.write('!x:1\n')
  8
  >>> ser.readline()
  'X:1\r\n'

If I write a python scrip and run it I don't get anything back. Here is my python script.

  import serial
  ser = serial.Serial('/dev/ttyUSB0', 115200)
  ser.write('!x:1\n')
  ser.readline()

I am new to Python so looking for some help to understand they this works in IDLE but not as a python script run from terminal.

Thanks.

Answer 1

Did you intend to have the string in the third line of your script start with an exclamation point? If not, that's your problem.

Answer 2

The solution for this really came down to a timing issue. The ser = serial.Serial('/dev/ttyUSB0', 115200) Needs to make the connection before sending any commands and the code I posted was just taking place too quick.