Python + Arduino on/off the LED.

pythonArduino.ino

#define LED 13

// Using http://slides.justen.eng.br/python-e-arduino as refference

void setup() {
    pinMode(LED, OUTPUT);
    Serial.begin(9600);
}

void loop() {
    if (Serial.available()) {
        char serialListener = Serial.read();
        if (serialListener == 'H') {
            digitalWrite(LED, HIGH);
        }
        else if (serialListener == 'L') {
            digitalWrite(LED, LOW);
        }
    }
}

PythonArduino.py

import serial # you need to install the pySerial :pyserial.sourceforge.net
import time
# your Serial port should be different!
arduino = serial.Serial('/dev/tty.usbmodem1411', 9600)

def onOffFunction():
  command = raw_input("Type something..: (on/ off / bye )");
	if command =="on":
		print "The LED is on..."
		time.sleep(1) 
		arduino.write('H') 
		onOffFunction()
	elif command =="off":
		print "The LED is off..."
		time.sleep(1) 
		arduino.write('L')
		onOffFunction()
	elif command =="bye":
		print "See You!..."
		time.sleep(1) 
		arduino.close()
	else:
		print "Sorry..type another thing..!"
		onOffFunction()

time.sleep(2) #waiting the initialization...

onOffFunction()