Reading serial data from Arduino

Question

I have am working on a project where I'm trying to get a Raspberry Pi to play some sounds when triggered by button presses on an Arduino. The command is sent to Raspberry Pi through serial. I used this tutorial to get started: http://blog.makezine.com/2012/10/22/a-halloween-sound-trigger-with-raspberry-pi-and-arduino/

I was able to get it to work as in the tutorial but my final product will be playing a lot more sounds and it will be playing different sounds on button ups and downs. I would like to be able to send commands through the serial similar to the following:

ButtonAPressed
ButtonAReleased
ButtonBPressed
Etc

I modified the tutorial to have my arduino script send 'Serial.write("ButtonAPressed")' and I modified the pertinent portion of the python script to look something like this:

while True:
    try:
        val = serialFromArduino.read()
        if (val != ""):
            print(val)
        if (val == "ButtonAPressed"): 
            soundChannelA.play(soundA) 
        if (val == "ButtonBPressed"):
            soundChannelB.play(soundB)
        if (val == "ButtonBReleased"):
            soundChannelC.play(soundC)
        val = ""
        sleep(.01)
    except KeyboardInterrupt: 
        exit()

The issue I'm having is my Print's are spitting out information similar to the following:

But
tonAPressed
ButtonBPr
essed
ButtonB
Released

So clearly the whole line isn't getting in the buffer before it's getting read. Is there a way I can make sure the whole line from arduino is in the buffer before it gets read? I don't want to increase the sleep because the button presses or press/release could be quite close together. For the sake of readability I would really rather not convert all of my commands to single characters.

Answer 1

This is just a wild guess but you could try adding a newline to the end on the arduino send.

Serial.write("ButtonAPressed\n")

On the python side add it to the == tests as well.