diff --git a/main.ino b/main.ino
new file mode 100644
index 0000000..ccd8c46
--- /dev/null
+++ b/main.ino
@@ -0,0 +1,40 @@
+int MODE = 8;
+
+int left_motor_in = 6;
+int left_motor_out = 9;
+
+int right_motor_in = 3;
+int right_motor_out = 5;
+
+void setup() {
+  Serial.begin(9600);
+  Serial.println("Start");
+  init_motor();
+}
+
+void loop() {
+  left_motor_go(250);
+  right_motor_go(250);
+}
+  
+void init_motor(){
+  pinMode(left_motor_in, OUTPUT);
+  pinMode(left_motor_out, OUTPUT);
+  
+  pinMode(right_motor_in, OUTPUT);
+  pinMode(right_motor_out, OUTPUT);
+
+  pinMode(MODE, OUTPUT);
+  digitalWrite(MODE, HIGH);
+  }
+
+//range:0<value<255
+void left_motor_go(int motor_speed){
+  analogWrite(left_motor_in, motor_speed);
+  digitalWrite(left_motor_out, LOW);
+ }
+//range:0<value<255
+void right_motor_go(int motor_speed){
+  analogWrite(right_motor_in, motor_speed);
+  digitalWrite(right_motor_out, LOW);
+}
diff --git a/pis-example.ino b/pis-example.ino
new file mode 100644
index 0000000..daf97e6
--- /dev/null
+++ b/pis-example.ino
@@ -0,0 +1,126 @@
+//Make sure to install the library
+#include <QTRSensors.h>
+QTRSensors qtr;
+const uint8_t SensorCount = 8;
+uint16_t sensorValues[SensorCount];
+
+float Kp = 0.07; //set up the constants value
+float Ki = 0.001;
+float Kd = 0.6;
+int P;
+int I;
+int D;
+
+int lastError = 0;
+boolean onoff = false;
+
+//Increasing the maxspeed can damage the motors - at a value of 255 the 6V motors will receive 7,4 V
+const uint8_t maxspeeda = 150;
+const uint8_t maxspeedb = 150;
+const uint8_t basespeeda = 100;
+const uint8_t basespeedb = 100;
+
+//Set up the drive motor carrier pins
+int mode = 8;
+int aphase = 6;
+int aenbl = 9;
+int bphase = 5;
+int benbl = 3;
+
+//Set up the buttons pins
+int buttoncalibrate = 17; //pin A3
+int buttonstart = 2;
+
+void setup() {
+  Serial.begin(9600);
+  qtr.setTypeRC();
+  //Set up the sensor array pins
+  qtr.setSensorPins((const uint8_t[]) {
+    10, 11, 12, 14, 15, 16, 18, 19
+  }, SensorCount);
+  qtr.setEmitterPin(7);//LEDON PIN
+
+  pinMode(mode, OUTPUT);
+  pinMode(aphase, OUTPUT);
+  pinMode(aenbl, OUTPUT);
+  pinMode(bphase, OUTPUT);
+  pinMode(benbl, OUTPUT);
+  digitalWrite(mode, HIGH);
+
+  delay(500);
+  pinMode(LED_BUILTIN, OUTPUT);
+
+  boolean Ok = false;
+  while (Ok == false) { //the loop won't start until the robot is calibrated
+    if (digitalRead(buttoncalibrate) == HIGH) {
+      calibration(); //calibrate the robot for 10 seconds
+      Ok = true;
+    }
+  }
+  forward_brake(0, 0);
+}
+
+void calibration() {
+  digitalWrite(LED_BUILTIN, HIGH);
+  for (uint16_t i = 0; i < 400; i++)
+  {
+    qtr.calibrate();
+  }
+  digitalWrite(LED_BUILTIN, LOW);
+}
+
+void loop() {
+  if (digitalRead(buttonstart) == HIGH) {
+    onoff = ! onoff;
+    if (onoff = true) {
+      delay(1000);//a delay when the robot starts
+    }
+    else {
+      delay(50);
+    }
+  }
+  if (onoff == true) {
+    PID_control();
+    Serial.print(">>>>>PID-control");
+  }
+  else {
+    forward_brake(0, 0);
+    Serial.print(">>>>>forward-brake");
+  }
+}
+void forward_brake(int posa, int posb) {
+  //set the appropriate values for aphase and bphase so that the robot goes straight
+  digitalWrite(aphase, HIGH);
+  digitalWrite(bphase, HIGH);
+  analogWrite(aenbl, posa);
+  analogWrite(benbl, posb);
+}
+void PID_control() {
+  uint16_t position = qtr.readLineBlack(sensorValues);
+  int error = 3500 - position;
+
+  P = error;
+  I = I + error;
+  D = error - lastError;
+  lastError = error;
+  int motorspeed = P * Kp + I * Ki + D * Kd;
+
+  int motorspeeda = basespeeda + motorspeed;
+  int motorspeedb = basespeedb - motorspeed;
+
+  if (motorspeeda > maxspeeda) {
+    motorspeeda = maxspeeda;
+  }
+  if (motorspeedb > maxspeedb) {
+    motorspeedb = maxspeedb;
+  }
+  if (motorspeeda < 0) {
+    motorspeeda = 0;
+  }
+  if (motorspeedb < 0) {
+    motorspeedb = 0;
+  }
+  Serial.print(motorspeeda);Serial.print(" ");Serial.println(motorspeedb);
+  Serial.print(position);
+  forward_brake(motorspeeda, motorspeedb);
+}
diff --git a/pis-examplev2.01.ino b/pis-examplev2.01.ino
new file mode 100644
index 0000000..cbb3f26
--- /dev/null
+++ b/pis-examplev2.01.ino
@@ -0,0 +1,161 @@
+  //Make sure to install the library
+#include <QTRSensors.h>
+QTRSensors qtr;
+const uint8_t SensorCount = 8;
+uint16_t sensorValues[SensorCount];
+
+float Kp = 0.07; //set up the constants value
+float Ki = 0.001;
+float Kd = 0.6;
+int P;
+int I;
+int D;
+
+int lastError = 0;
+boolean onoff = false;
+
+//Increasing the maxspeed can damage the motors - at a value of 255 the 6V motors will receive 7,4 V
+const uint8_t maxspeeda = 120;
+const uint8_t maxspeedb = 120;
+const uint8_t basespeeda = 100;
+const uint8_t basespeedb = 100;
+
+//Set up the drive motor carrier pins
+int mode = 8;
+/*int aphase = 9;
+int aenbl = 6;
+int bphase = 5;
+int benbl = 3;*/
+
+int aphase = 6;
+int aenbl = 9;
+
+int bphase = 3;
+int benbl = 5;
+
+
+
+//Set up the buttons pins
+int buttoncalibrate = 17; //pin A3
+int buttonstart = 2;
+
+void setup() {
+  Serial.begin(9600);
+  qtr.setTypeRC();
+  //Set up the sensor array pins
+  qtr.setSensorPins((const uint8_t[]) {
+    10, 11, 12, 14, 15, 16, 18, 19
+  }, SensorCount);
+  qtr.setEmitterPin(7);//LEDON PIN
+
+  pinMode(mode, OUTPUT);
+  pinMode(aphase, OUTPUT);
+  pinMode(aenbl, OUTPUT);
+  pinMode(bphase, OUTPUT);
+  pinMode(benbl, OUTPUT);
+  digitalWrite(mode, HIGH);
+
+  delay(500);
+  pinMode(LED_BUILTIN, OUTPUT);
+
+  //Stephanos code - LED will blink for 3 seconds and then 
+  /*   calibration will begin running for 10 seconds;
+     this happens when our system boots. Giorgo i removed
+     the functionality to calibrate through the button keypress.*/
+  for (int counter=0; counter < 3;counter++){
+    digitalWrite(LED_BUILTIN, HIGH);
+    delay(500);
+    digitalWrite(LED_BUILTIN, LOW);
+    delay(500);
+  }
+  calibration();  
+  //When calibration is compelted we understand that by blinking the LED for
+   //5 times in a period of 2 seconds, faster than getting ready for calibration
+   for (int counter=0; counter < 3;counter++){
+    digitalWrite(LED_BUILTIN, HIGH);
+    delay(200);
+    digitalWrite(LED_BUILTIN, LOW);
+    delay(200);
+  }
+  
+  //modified by Stephanos - commented out
+  /*boolean Ok = false;
+  while (Ok == false) { //the loop won't start until the robot is calibrated
+    if (digitalRead(buttoncalibrate) == HIGH) {
+      calibration(); //calibrate the robot for 10 seconds
+      Ok = true;
+    }
+  }*/
+  
+  forward_brake(0, 0);
+}
+
+void calibration() {
+  digitalWrite(LED_BUILTIN, HIGH);
+  for (uint16_t i = 0; i < 400; i++)
+  {
+    qtr.calibrate();
+  }
+  digitalWrite(LED_BUILTIN, LOW);
+  Serial.print("Calibration COMPLETED!!!");
+}
+
+
+void loop() {
+  /*if (digitalRead(buttonstart) == HIGH) {
+    onoff = ! onoff;
+    if (onoff = true) {
+      delay(1000);//a delay when the robot starts
+    }
+    else {
+      delay(50);
+    }
+  }*/
+  delay(3000);// a small 3 seconds delay before starting our rebot
+  PID_control();
+  
+  /*if (onoff == true) {
+    PID_control();
+  }
+  else {
+    forward_brake(0, 0);
+  }*/
+}
+
+
+void forward_brake(int posa, int posb) {
+  //set the appropriate values for aphase and bphase so that the robot goes straight
+  digitalWrite(aphase, HIGH);
+  digitalWrite(bphase, HIGH);
+  analogWrite(aenbl, posa);
+  analogWrite(benbl, posb);
+}
+
+void PID_control() {
+  uint16_t position = qtr.readLineBlack(sensorValues);
+  int error = 3500 - position;
+
+  P = error;
+  I = I + error;
+  D = error - lastError;
+  lastError = error;
+  int motorspeed = P * Kp + I * Ki + D * Kd;
+
+  int motorspeeda = basespeeda + motorspeed;
+  int motorspeedb = basespeedb - motorspeed;
+
+  if (motorspeeda > maxspeeda) {
+    motorspeeda = maxspeeda;
+  }
+  if (motorspeedb > maxspeedb) {
+    motorspeedb = maxspeedb;
+  }
+  if (motorspeeda < 0) {
+    motorspeeda = 0;
+  }
+  if (motorspeedb < 0) {
+    motorspeedb = 0;
+  }
+  Serial.print(motorspeeda);Serial.print(" ");Serial.println(motorspeedb);
+  forward_brake(motorspeeda, motorspeedb);
+}
diff --git a/qtr-test.ino b/qtr-test.ino
new file mode 100644
index 0000000..6c18af7
--- /dev/null
+++ b/qtr-test.ino
@@ -0,0 +1,93 @@
+//Made by POLULU
+
+#include <QTRSensors.h>
+
+// This example is designed for use with eight RC QTR sensors. These
+// reflectance sensors should be connected to digital pins 3 to 10. The
+// sensors' emitter control pin (CTRL or LEDON) can optionally be connected to
+// digital pin 2, or you can leave it disconnected and remove the call to
+// setEmitterPin().
+//
+// The setup phase of this example calibrates the sensors for ten seconds and
+// turns on the Arduino's LED (usually on pin 13) while calibration is going
+// on. During this phase, you should expose each reflectance sensor to the
+// lightest and darkest readings they will encounter. For example, if you are
+// making a line follower, you should slide the sensors across the line during
+// the calibration phase so that each sensor can get a reading of how dark the
+// line is and how light the ground is.  Improper calibration will result in
+// poor readings.
+//
+// The main loop of the example reads the calibrated sensor values and uses
+// them to estimate the position of a line. You can test this by taping a piece
+// of 3/4" black electrical tape to a piece of white paper and sliding the
+// sensor across it. It prints the sensor values to the serial monitor as
+// numbers from 0 (maximum reflectance) to 1000 (minimum reflectance) followed
+// by the estimated location of the line as a number from 0 to 5000. 1000 means
+// the line is directly under sensor 1, 2000 means directly under sensor 2,
+// etc. 0 means the line is directly under sensor 0 or was last seen by sensor
+// 0 before being lost. 5000 means the line is directly under sensor 5 or was
+// last seen by sensor 5 before being lost.
+
+QTRSensors qtr;
+
+const uint8_t SensorCount = 8;
+uint16_t sensorValues[SensorCount];
+
+void setup()
+{
+  // configure the sensors
+  qtr.setTypeRC();
+  qtr.setSensorPins((const uint8_t[]){10, 11, 12, 14, 15, 16, 18, 19}, SensorCount);
+  qtr.setEmitterPin(7);
+
+  delay(500);
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, HIGH); // turn on Arduino's LED to indicate we are in calibration mode
+
+  // 2.5 ms RC read timeout (default) * 10 reads per calibrate() call
+  // = ~25 ms per calibrate() call.
+  // Call calibrate() 400 times to make calibration take about 10 seconds.
+  for (uint16_t i = 0; i < 400; i++)
+  {
+    qtr.calibrate();
+  }
+  digitalWrite(LED_BUILTIN, LOW); // turn off Arduino's LED to indicate we are through with calibration
+
+  // print the calibration minimum values measured when emitters were on
+  Serial.begin(9600);
+  for (uint8_t i = 0; i < SensorCount; i++)
+  {
+    Serial.print(qtr.calibrationOn.minimum[i]);
+    Serial.print(' ');
+  }
+  Serial.println();
+
+  // print the calibration maximum values measured when emitters were on
+  for (uint8_t i = 0; i < SensorCount; i++)
+  {
+    Serial.print(qtr.calibrationOn.maximum[i]);
+    Serial.print(' ');
+  }
+  Serial.println();
+  Serial.println();
+  delay(1000);
+}
+
+void loop()
+{
+  // read calibrated sensor values and obtain a measure of the line position
+  // from 0 to 5000 (for a white line, use readLineWhite() instead)
+  uint16_t position = qtr.readLineBlack(sensorValues);
+
+  // print the sensor values as numbers from 0 to 1000, where 0 means maximum
+  // reflectance and 1000 means minimum reflectance, followed by the line
+  // position
+  for (uint8_t i = 0; i < SensorCount; i++)
+  {
+    Serial.print(sensorValues[i]);
+    Serial.print('\t');
+  }
+  Serial.println(position);
+
+  delay(250);
+}