PING))) Sensor Ultrasonico para medir distancia

PING))) é um sensor ultrasonico, fabricado pela empresa Parallax. Ele detecta a distancia de objetos em frente ao sensor (+/- 3m). Ele trabalha enviando sinais de ultrasom e os recebendo de volta pelo principio do eco quando este encontrar um objeto. O Arduino irá calcular a distancia a partir do sinal enviado pelo PING))), sendo assim a duração do sinal (pulso) é proporcional a sua distancia.


Pode ser facilmente encontrado no ML (Mercado Livre.com).

Circuito:

O pino 5V do PING))) é conectado ao pino 5V do Arduino, o pino GND ao GND e o pino SIG (sinal) é conectado ao pino digital 7 do arduino.

Sketch:

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;
 }