Python->Arduino communication example

serial_example.ino

void setup() {
  Serial.begin(9600);
  pinMode(13, OUTPUT);
}

void loop() {
  String serialString;
  while (Serial.available()) {
    serialString += Serial.read();
  }

  
  if (serialString == "119") {
    digitalWrite(13, 1);
  }
  else if (serialString == "115") {
    digitalWrite(13, 0);
  }
}

serial_example.py

import serial

print('Starting USB')
# Change /dev/ttyACM0 for COMX if on Windows
s = serial.Serial('/dev/ttyACM0', 9600, timeout=1)

while (1):
    # Change raw_input for input if using Python 3
    key=raw_input('Enter key:\n').strip()

    if key=='w':
        s.write("w".encode("ascii"))

    if key=='s':
        s.write("s".encode("ascii"))