Improved and added Ultrasonic Sensor code

Arduino/Ultrasonic_Code/ultrasonic_code.ino

@@ -0,0 +1,37 @@
+
+const int TRIG_PIN = 6;
+const int ECHO_PIN = 7;
+const int LED_PIN = 13;
+const int DISTANCE_THRESHOLD = 50;
+
+float duration_us, distance_cm;
+
+void setup() {
+  Serial.begin (9600);
+  pinMode(TRIG_PIN, OUTPUT);
+  pinMode(ECHO_PIN, INPUT);
+  pinMode(LED_PIN, OUTPUT);
+}
+
+void loop() {
+  digitalWrite(TRIG_PIN, HIGH);
+  delayMicroseconds(10);
+  digitalWrite(TRIG_PIN, LOW);
+
+  duration_us = pulseIn(ECHO_PIN, HIGH);
+
+  distance_cm = 0.017 * duration_us;
+
+  if(distance_cm < DISTANCE_THRESHOLD)
+    digitalWrite(LED_PIN, HIGH);
+
+  else
+    digitalWrite(LED_PIN, LOW);
+
+  Serial.print("distance:");
+  Serial.print(distance_cm);
+  Serial.println(" cm");
+
+  delay(500);
+
+}