Full Xmas-Tree code

/**
xmas tree worm full working edition 02
completed at 19hrs 23/10/2008
Created by pete-rogers.co.uk

Connectors:
Servo to pin 10
Analog sensor to pin 2

Things you can change:
Threshold (int) changes the level at which the sensor triggers the servo
if it is higher than threshold servo triggered...
timerLength(int) changes the timer that holds in the worm...
inExtreme(int) the in amount of the servo. Needs to be callibrated
outExtreme(int)the out amount of the servo. Needs to be callibrated
alpha controls the amount of smoothing needed for the analog signal, higher the smoother
**/

//constants
int servoPin = 10;
int oldRot = 500;
int sensorPin = 2;
int sec = 0; // this timer is for the delay for the worm to keep hiding
int timer = 0;


//configerable
int timerLength = 100;
int alpha = 15;
int threshold = 50;
int inExtreme = 2500;
int outExtreme = 500;

//vars
boolean extended;
boolean retracted;
int smoothed;
int sensorNum;


void setup(){
  Serial.begin(9600);
  Serial.println("initialised");
  servoIn(2500);
}

void loop (){
    sensorNum = checkSensor();
    sec  = sec + 1;
    if(sec > 1000){
      Serial.println(sensorNum);
         timer = timer + 1;
         sec = 0;
     }
    if (sensorNum < threshold){
         timer = 0;
         if (retracted == false){
             Serial.println("go in");
             servoIn(inExtreme);
           }

     }

    if (timer > timerLength && extended == false){
        Serial.println("go out");
        servoOut(outExtreme);
        timer = 0;
    }   
}//end loop


//checks the sensor
int checkSensor(){
   int rawValue = analogRead(sensorPin);
   if (rawValue > smoothed){
     smoothed = smoothed + (rawValue - smoothed)/alpha;
   }else{
     smoothed = smoothed -(smoothed - rawValue)/alpha;
   }
   int i = smoothed;
   return i;
}

void servoOut(int rot){
  retracted = false;
   Serial.println("out started");
    while (true){
             if (oldRot == rot){
                 Serial.println(oldRot);
                  extended = true;
               break;
              }
 //check to see if sensor has detected anything whilst worm is extending             
             sensorNum = checkSensor();
             
             if( sensorNum < threshold){
              Serial.println(sensorNum);
              servoIn(inExtreme);
              break;
             
          }
        digitalWrite(servoPin, HIGH);   // Turn the motor on
        delayMicroseconds(oldRot);       // Length of the pulse sets the motor position
        digitalWrite(servoPin, LOW);    // Turn the motor off
        oldRot = oldRot - 1;
        delay(20);
  }
  Serial.println("out completed");
}//end servoOut

void servoIn(int rot){
  extended = false;
  Serial.println("in started");
   for (int i = 0; i < 1000; i ++){
        digitalWrite(servoPin, HIGH);   // Turn the motor on
        delayMicroseconds(rot);       // Length of the pulse sets the motor position
        digitalWrite(servoPin, LOW);    // Turn the motor off
   }
        oldRot = rot;
        timer = 0;
   Serial.println("in completed");
   retracted = true;
  
}//end servoIn