Parallax Continuous Servo example (http://www.parallax.com/product/900-00025)

parallax-servo-continuos-test.ino

#include <Servo.h> 
// Parallax Continuous Servo example (http://www.parallax.com/product/900-00025)
// Read values from serial and set the speed of the servo
// Range 0 to 180; 90 is no movement
// Remember to set the proper baud rate and carriage return settings

Servo theServo; 
int gSpeed = 90;
 
void setup() 
{ 
  Serial.begin(9600);
  theServo.attach(9);  // attaches the servo on pin 9 to the servo object 
} 
 
void loop() 
{ 
  while (Serial.available() > 0) {
    gSpeed = Serial.parseInt();
    if (Serial.read() == '\n') {
      gSpeed = constrain(gSpeed, 0, 180);
      Serial.print(gSpeed, HEX);
      theServo.write(gSpeed);
    }
  }
  delay(20);
}