The hidden door project

The Arduino circuit and code for "Blossom".

/* HC-SR04 Sensor

   https://www.dealextreme.com/p/hc-sr04-ultrasonic-sensor-distance-measuring-module-133696

      This sketch reads a HC-SR04 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:

* VCC connection of the sensor attached to +5V

* GND connection of the sensor attached to ground

* TRIG connection of the sensor attached to digital pin 2

* ECHO connection of the sensor attached to digital pin 4

   Original code for Ping))) example was created by David A. Mellis

   Adapted for HC-SR04 by Tautvidas Sipavicius

   This example code is in the public domain.

 */

#include <Servo.h> 

Servo myservo;  // create servo object to control a servo 

                // a maximum of eight servo objects can be created 

  int pos = 0;    // variable to store the servo position 

int led = 7;    // led pin

  const int trigPin = 2;

const int echoPin = 4;

  void setup() {

  // initialize serial communication:

  Serial.begin(9600);

  digitalWrite(13, HIGH);

  digitalWrite(12, LOW);

  myservo.attach(9);  // attaches the servo on pin 9 to the servo object

  pinMode(led, OUTPUT);    

}

  void loop()

{

  // establish variables for duration of the ping, 

  // and the distance result in inches and centimeters:

  long duration, inches, cm;

    // The sensor is triggered by a HIGH pulse of 10 or more microseconds.

  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:

  pinMode(trigPin, OUTPUT);

  digitalWrite(trigPin, LOW);

  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

    // Read the signal from the sensor: 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(echoPin, INPUT);

  duration = pulseIn(echoPin, 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);

        if (cm < 30) {

   digitalWrite(13, HIGH);

   digitalWrite(12, LOW);

   digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)

   pos = 180;

   myservo.write(pos);              // tell servo to go to position in variable 'pos'

   delay(15);                       // waits 15ms for the servo to reach the position  

   } else {

   digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW 

   pos = 0;

   myservo.write(pos);              // tell servo to go to position in variable 'pos'

   delay(15);                       // waits 15ms for the servo to reach the position

 }     

}

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;

summer---red      winter---white

initial model for testing.