como programar un sensor ultasonico en el material arduino

En el mismo soft de arduino tenes el ejemlo como Ping, esta en Sensor-ping aca va el sketch /* Ping))) Sensor This sketch reads a PING))) ultrasonic rangefinder and returns the distance to the closest object in range. To do this, it sends a pulse to the sensor to initiate a reading, then listens for a pulse to return. The length of the returning pulse is proportional to the distance of the object from the sensor. The circuit: * +V connection of the PING))) attached to +5V * GND connection of the PING))) attached to ground * SIG connection of the PING))) attached to digital pin 7 http://www.arduino.cc/en/Tutorial/Ping created 3 Nov 2008 by David A. Mellis modified 30 Aug 2011 by Tom Igoe This example code is in the public domain. */ // this constant won't change. It's the pin number // of the sensor's output: const int pingPin = 7; void setup() { // initialize serial communication: Serial.begin(9600); } void loop() { // establish variables for duration of the ping, // and the distance result in inches and centimeters: long duration, inches, cm; // The PING))) is triggered by a HIGH pulse of 2 or more microseconds. // Give a short LOW pulse beforehand to ensure a clean HIGH pulse: pinMode(pingPin, OUTPUT); digitalWrite(pingPin, LOW); delayMicroseconds(2); digitalWrite(pingPin, HIGH); delayMicroseconds(5); digitalWrite(pingPin, LOW); // The same pin is used to read the signal from the PING))): a HIGH // pulse whose duration is the time (in microseconds) from the sending // of the ping to the reception of its echo off of an object. pinMode(pingPin, INPUT); duration = pulseIn(pingPin, HIGH); // convert the time into a distance inches = microsecondsToInches(duration); cm = microsecondsToCentimeters(duration); Serial.print(inches); Serial.print("in, "); Serial.print(cm); Serial.print("cm"); Serial.println(); delay(100); } long microsecondsToInches(long microseconds) { // According to Parallax's datasheet for the PING))), there are // 73.746 microseconds per inch (i.e. sound travels at 1130 feet per // second). This gives the distance travelled by the ping, outbound // and return, so we divide by 2 to get the distance of the obstacle. // See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf return microseconds / 74 / 2; } long microsecondsToCentimeters(long microseconds) { // The speed of sound is 340 m/s or 29 microseconds per centimeter. // The ping travels out and back, so to find the distance of the // object we take half of the distance travelled. return microseconds / 29 / 2; }