Beating Heart - Alec Rippberger
This piece of artwork blinks as if it were alive and beating! The closer you approach the faster the heart "beats". I used several LEDs attached to 1k resistors embedded in the semi transparent sculpture of a "heart". These LEDs ran into the digital pins of the arduino and were controlled by the following code:
/* 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 Jun 2009
by Tom Igoe
*/
// this constant won't change. It's the pin number
// of the sensor's output:
const int pingPin = 7;
//variables for digital pins one through five used as LEDs
int pinSix = 6;
int pinTwo = 2;
int pinThree = 3;
int pinFour = 4;
int pinFive = 5;
void setup() {
// initialize serial communication
Serial.begin(9600);
// set pinmode for LEDs
pinMode(pinSix, OUTPUT);
pinMode(pinTwo, OUTPUT);
pinMode(pinThree, OUTPUT);
pinMode(pinFour, OUTPUT);
pinMode(pinFive, OUTPUT);
}
void loop()
{
int beat = 1000;
int unbeat = 2000;
int rest = 3000;
// 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();
beat = inches * 6;
unbeat = inches * 5.5;
rest = inches * 18;
digitalWrite(pinSix, HIGH);
digitalWrite(pinTwo, HIGH);
digitalWrite(pinThree, HIGH);
digitalWrite(pinFour, HIGH);
digitalWrite(pinFive, HIGH);
delay(beat);
digitalWrite(pinSix, LOW);
digitalWrite(pinTwo, LOW);
digitalWrite(pinThree, LOW);
digitalWrite(pinFour, LOW);
digitalWrite(pinFive, LOW);
delay(beat);
digitalWrite(pinSix, HIGH);
digitalWrite(pinTwo, HIGH);
digitalWrite(pinThree, HIGH);
digitalWrite(pinFour, HIGH);
digitalWrite(pinFive, HIGH);
delay(unbeat);
digitalWrite(pinSix, LOW);
digitalWrite(pinTwo, LOW);
digitalWrite(pinThree, LOW);
digitalWrite(pinFour, LOW);
digitalWrite(pinFive, LOW);
delay(rest);
}
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;
}