Mouvement detection arduino accelerometres

/*
* Accelerometer input
* Takes the input from a lilypad accelerometer on analog pins 0=x, 1=y, 2=z
* Detect the movment of each accelerometer
*/

int buttonpin = 2;
// pied droit
int xpin = 3; // select the input pin for the sensor
int ypin = 4; // select the input pin for the sensor
int zpin = 5; // select the input pin for the sensor

int yval = 0; // variable to store the value coming from the x axis
int yval_prec = 0;
int xval = 0; // variable to store the value coming from the x axis
int xval_prec = 0; // variable to store the value coming from the x axis
int zval = 0; // variable to store the value coming from the x axis
int zval_prec = 0;

int zdir=90;  //initial z orientation is "up"

//pied gauche
int xpinG = 2;
int ypinG = 1;
int zpinG = 0;

int yvalG = 0; // variable to store the value coming from the x axis
int yvalG_prec = 0;
int xvalG = 0; // variable to store the value coming from the x axis
int xvalG_prec = 0;
int zvalG = 0; // variable to store the value coming from the x axis
int zvalG_prec = 0;

int initialise = 1;
int delta =20;
int isolement_mouvement_init = 3;
int isolement_mouvement = 3;

int marche=0;

int normeG=0;
int norme=0;
int normeG_init=0;
int norme_init=0;

int delai = 0;
int temps_echantillonage = 80;
int temps_init = 0;
int up=390; int down=290; int mid=(up+down)/2;

void setup() {
  Serial.begin(9600);
  pinMode(buttonpin, INPUT);

  //Serial.print("normeG_init  =");Serial.println(normeG_init);

  isolement_mouvement = isolement_mouvement_init;
}

void loop() {

  if(marche>=1){
    //Serial.print("marche");
    xval = analogRead(xpin); // read the value from the x axis, 0-1023
    yval = analogRead(ypin); // read the value from the y axis, 0-1023
    zval = analogRead(zpin); // read the value from the z axis, 0-1023
    xvalG = analogRead(xpinG); // read the value from the x axis, 0-1023
    yvalG = analogRead(ypinG); // read the value from the y axis, 0-1023
    zvalG = analogRead(zpinG); // read the value from the z axis, 0-1023

    displayvalues();
    delay(temps_echantillonage); // rest a little...
    if(digitalRead(buttonpin)==0){ // si on appuye sur le bouton -> arret
      marche++;
      if (marche>3){
        Serial.print("stop");
        marche=-1;
      }
    }

  } else if(marche==0){
    if(digitalRead(buttonpin)==0){// si on appuye sur le bouton -> marche
      marche=1;
      initialisationVariables();
    }
  }

}

void displayvalues(){
int zorientation; int yorientation; int xorientation;
int zorientationG; int yorientationG; int xorientationG;

isolement_mouvement--;
//Serial.print(" : x="); Serial.print(xval);
if (isolement_mouvement <= 0) {

  normeG = sqrt(((xvalG_prec-xvalG)*(xvalG_prec-xvalG))+((yvalG_prec-yvalG)*(yvalG_prec-yvalG))+((zvalG_prec-zvalG)*(zvalG_prec-zvalG)));
  norme = sqrt(((xval_prec-xval)*(xval_prec-xval))+((yval_prec-yval)*(yval_prec-yval))+((zval_prec-zval)*(zval_prec-zval)));
  /*Serial.print("norme :");Serial.println(norme);
  Serial.print("normeG :");Serial.println(normeG);*/

  if(((normeG>(normeG_init+delta)) || (normeG<(normeG_init-delta)))&&(initialise==1)){
    Serial.print(millis()/1000.0);
    /*Serial.print("Deplacement G (");
    Serial.print(normeG);
    Serial.println(")");*/
    Serial.print(",");
    initialise=0;
  } else if(((norme>(norme_init+delta)) || (norme<(norme_init-delta)))&&(initialise==1)){
    Serial.print(millis()/1000.0);
    /*Serial.print("Deplacement (");
    Serial.print(norme);
    Serial.println(")");*/
    Serial.print(",");
    initialise=0;
  } else {//pour eviter de prendre un déplacement pour plusieurs
    initialise = 1;
  }

  isolement_mouvement = isolement_mouvement_init;

}


}


void initialisationVariables(){
  xval_prec = analogRead(xpin);
  yval_prec = analogRead(ypin);
  zval_prec = analogRead(zpin);
  xvalG_prec = analogRead(xpinG);
  yvalG_prec = analogRead(ypinG);
  zvalG_prec = analogRead(zpinG);
  xval = analogRead(xpin); // read the value from the x axis, 0-1023
  yval = analogRead(ypin); // read the value from the y axis, 0-1023
  zval = analogRead(zpin); // read the value from the z axis, 0-1023
  xvalG = analogRead(xpinG); // read the value from the x axis, 0-1023
  yvalG = analogRead(ypinG); // read the value from the y axis, 0-1023
  zvalG = analogRead(zpinG); // read the value from the z axis, 0-1023
  normeG_init = sqrt(((xvalG_prec-xvalG)*(xvalG_prec-xvalG))+((yvalG_prec-yvalG)*(yvalG_prec-yvalG))+((zvalG_prec-zvalG)*(zvalG_prec-zvalG)));
  norme_init = sqrt(((xval_prec-xval)*(xval_prec-xval))+((yval_prec-yval)*(yval_prec-yval))+((zval_prec-zval)*(zval_prec-zval)));

  Serial.print("[");
}