My final projects incorporates multiple neropixles, an ultrasonic sensor and some tissue paper. The piece would be hanging on a wall with the sensor facing out. This sensor used an echolocation method to judge distance. When left alone the paper is dark, but as someone walks up to it lights will appear. As the viewer comes closer to the piece the lights will respond to the change in distance by becoming creating new color patterns. For this project I used 15 neopixles wires up in a snaking line and then glued these lights to a single sheet of paper. On top of these I put tissue paper in order to diffuse the lights and create more abstract lighting.
Materials used:
- ultasonic sensor
- wire cutters and wire strippers
- white tissue paper
- solder and soldering iron
- hot glue
- various jumper wires
- Arduino uno
The first two photos are of the the inner workings of the piece as well as the wiring setup for the ultrasonic sensor.
The photo to the right is of the enclosed lights connected to the sensor.
When an object is close, less than 10 inches blue,white, and purple lights glow.
When an object is less than 30 inches but greater than 10 red, orange and yellow lights will start to glow.
Below is a video of this piece working.
Arduino Code:
// Turning NeoPixels on and off using a HC-SRO4 Ping Sensor
/*
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 Arduino then takes this information and illuminates a strip
NeoPixel’s based on the distance of the object from the sensor.
This code was developed partially from Ping))) code found in
the public domainwritten by David A. Mellis, and adapted to the
HC-SRO4 by Tautvidas Sipavicius, while other portions were
written by Charles Gantt and Curtis Gauger from
http://www.themakersworkbench.com.
*/
//Tell the Arduino IDE to include the FastLED library
#include <FastLED.h>
//Setup the variables for the HC-SR04
const int trigPin = 8;
const int echoPin = 7;
//Setup the variables for the NeoPixel Strip
// How many leds in your strip?
#define NUM_LEDS 15
// What pin is the NeoPixel’s data line connected to?
#define DATA_PIN 6
// Define the array of leds
CRGB leds[NUM_LEDS];
// from other sketch
#define BRIGHTNESS 64
#define LED_TYPE WS2811
#define COLOR_ORDER GRB
//CRGB leds[NUM_LEDS];
#define UPDATES_PER_SECOND 100
CRGBPalette16 currentPalette;
TBlendType currentBlending;
#define LED_PIN 6
extern CRGBPalette16 myRedWhiteBluePalette;
extern const TProgmemPalette16 myRedWhiteBluePalette_p PROGMEM;
void setup()
{
// initialize serial communication:
Serial.begin(9600);
FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
delay( 3000 ); // power-up safety delay
FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
FastLED.setBrightness( BRIGHTNESS );
currentPalette = RainbowColors_p;
currentBlending = LINEARBLEND;
}
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();
//CLoser than 20 inches
if (inches <= 30)
//fill_solid( &(leds[0]), NUM_LEDS, CRGB::Green);
//FastLED.show();
{
//From 0 to 10 inches
if ((inches < 30) && (inches >= 15))
{
for(int dot = 0; dot < NUM_LEDS; dot++)
{
leds[dot ] = CRGB::Yellow;
leds[dot+1] = CRGB:: Yellow;
leds[dot+3] = CRGB::Red;
leds[dot-3] = CRGB::Yellow;
leds[dot-4] = CRGB::Red;
leds[dot-5] = CRGB::Red;
FastLED.show();
// clear this led for the next time around the loop
leds[dot] = CRGB::Orange;
delay(100);
}
}
//From 0 to 10 inches
else
{
for(int dot = 0; dot < NUM_LEDS; dot++)
{
leds[dot] = CRGB::Blue;
leds[dot+1] = CRGB:: White;
leds[dot+3] = CRGB::Blue;
leds[dot-3] = CRGB::Blue;
leds[dot-4] = CRGB:: White;
leds[dot-5] = CRGB::Blue;
FastLED.show();
// clear this led for the next time around the loop
leds[dot] = CRGB::Purple;
delay(100);
}
}
}
// From 20 to 40 inches
if (inches >= 41)
{
fill_solid( &(leds[0]), NUM_LEDS, CRGB::Black);
FastLED.show();
}
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;
}