const int pingPin = 7; Servo myservo; int pos = 0;
void setup() { // initialize serial communication: Serial.begin(9600); myservo.attach(9); }
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(); if (inches <= 6) {sweep(1);} else if (inches >= 6) {myservo.write(pos);} 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;
}
void sweep(int NUM_OF_CYCLES)
{
// Tells the Arduino to start this loop at 0 and incriment it by 1
// each time the loop completes. This is how the Arduino knows to
// stop the loop when a specific number of the // Sweep routein has been ran.
for (int j=0; j<NUM_OF_CYCLES; j++) // goes from 0 degrees to 40 degrees for(pos = 0; pos < 40; pos += 1) { // in steps of 1 degree // tell servo to go to position in variable 'pos' myservo.write(pos); // waits 15ms for the servo to reach the position delay(10); } // goes from 40 degrees to 0 degrees for(pos = 40; pos>=1; pos-=1) { // tell servo to go to position in variable 'pos' myservo.write(pos); // waits 15ms for the servo to reach the position delay(10);}}}