diff --git a/arduino/sketchDistanceSerial-Ultrasonic.ino b/arduino/sketchDistanceSerial-Ultrasonic.ino
index df14921..9256f1c 100644
--- a/arduino/sketchDistanceSerial-Ultrasonic.ino
+++ b/arduino/sketchDistanceSerial-Ultrasonic.ino
@@ -1,13 +1,20 @@
+
 #include "Ultrasonic.h"
-Ultrasonic sensor(8,9); // Trig et Echo
+
+#define echoPin 9 // attach pin D2 Arduino to pin Echo of HC-SR04
+#define trigPin 8 //attach pin D3 Arduino to pin Trig of HC-SR04
+
+Ultrasonic sensor(trigPin,echoPin); // Trig et Echo
  
 // defines variables
 int distance; // variable for the distance measurement
 
 void setup() {
-  Serial.begin(9600);
-  pinMode (11, OUTPUT);
-  pinMode (12, OUTPUT);
+  Serial.begin(9600);trigPin as an OUTPUT
+  pinMode(echoPin, INPUT); // Sets the echoPin as an INPUT
+  Serial.begin(9600); // // Serial Communication is starting with 9600 of baudrate speed
+  Serial.println("Ultrasonic Sensor HC-SR04 Test"); // print some text in Serial Monitor
+  Serial.println("with Arduino UNO R3 and Ultrasonic.h");
 }
 
 void loop () {