ArtOnTheRise2016-SAS

#include <Servo.h>

Servo myservo;  // create servo object to control a servo

// int potpin = 0;  // analog pin used to connect the potentiometer
int val;    // variable to read the value from the analog pin
char ser;

void setup() {
  Serial.begin(9600);
  
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
}

void loop() {
  
  if (Serial.available() > 0) {
    ser = Serial.read();
  }
  if (ser == '4'){
    myservo.write(10);
  }
  if (ser == '3'){
    myservo.write(30);
  }
  if (ser == '2'){
    myservo.write(60);
  }
  if (ser == '1'){
    myservo.write(75);
  }
  if (ser == 's'){
    myservo.write(150);
  }
  // val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023)
       // scale it to use it with the servo (value between 0 and 180)
  //myservo.write(val);                  // sets the servo position according to the scaled value
  delay(15);                           // waits for the servo to get there
}

###########################

Raspberry Pi:

import serial
print("press 'f' to go Fast")
print("press 'm' to go Medium speed")
print("press 's' to Stop")
print("press 'q' to quit")
print("")
print("")
ser = serial.Serial('/dev/ttyACM0', 9600)
while 1:
        var = raw_input()

        if var  == 'f':
                print("Fast")
                ser.write('a')
                print("")
        elif var == 'm':
                print("Medium")
                ser.write('b')
                print("")

        elif var == 's':
                print("Stop")
                ser.write('c')
                print("")
        elif var == 'q':
                print("quitting ......")
                quit()