Published March 3, 2015 © GPL

Halloween project: Blue Girl

IR proximity sensor that lights up LEDs embedded in a Blue Girl painting for a Halloween party.

IntermediateFull instructions provided1,064

Things used in this project

Hardware components

RADIOSHACK® INFRARED LED EMITTER AND DETECTOR @$3.59

Emitter Specs (tinted package): Reverse voltage: 5VCont.; forward current: 150mA; Forward voltage: 1.3V typical, 1.7V max; Wavelength (peak emission): 950nm Detector Specs (max): IC (collector current)50mA; Peak sensitivity wavelength: 850nm

Resistors: 70 Ohms, and 38 KOhms

SparkFun RedBoard

Story

A Halloween project! Someone in my art group found a bunch of these framed Blue Girl paintings. Each person took their own, and altered it in some way. I added an IR proximity sensor that would turn on the red LEDs behind the eyes when you get too close... creeeeepy!

1 / 3 • Full painting

1 / 6 • ASCII diagram. Note the direction of the diode |<|. This creates an open circuit until light activates the diode, which is exactly the behavior that we want.

Discussion:

I originally wanted to have the project blink in response to the proximity sensor, but as I prototyped that, it was looking exceedingly difficult to get the blinking mechanism to work. Instead, I opted for the red LEDs lighting up behind the eyes. One of the trickiest parts was cutting the eyes out, and creating a gap for the light to shine through. I don't love how it turned out, but I had a great time making the proximity sensor.

The key to getting everything to work was to remember the way the detector diode works. Basically, the light activates the receiver diode, which then begins conducting electricity, causing the voltage on A0 to go up to ~5V. When no IR light is activating it, the diode is off, and there is very little voltage on A0.

If I did this again, I'd find a better way to make the light shine through the eyes. Maybe I'd print the eyeballs on some vellum, or other see-through paper, and then have the light diffuse through that. Or else cut around just the irises.

References:

Makezine: Use a DIY proximity sensor to automate your haunted house.

Arduino: Simple IR Distance Sensor Tutorial.

Basic LED tutorial.

LED-laden bike helmet tutorial.

Code

file_14083.txt

int inputPin = A0; // analog pin 0 is the input pin  
int val = 0; // variable to store the value read 
int redEyes = 8; // turns on the red LED for glowing eyes effect.
int highThreshold = 13;

void setup() { 
  Serial.begin(9600);         // initializing Serial monitor
  pinMode(redEyes, OUTPUT);
} 

void loop() { 

  digitalWrite(redEyes, LOW);
  val = analogRead(InputPin); // read the input pin 0 to 1023 

  Serial.println( val);
  if (val >= high_threshold)
  { 
    digitalWrite(redEyes, HIGH);
    delay(1000);
  } 
   
}

Credits

Molly Nicholas

9 projects • 8 followers

I ran away from the Circus to join Science.

Halloween project: Blue Girl

Things used in this project

Hardware components

Story

BlueGirl.fzz

Schematics

BlueGirl.fzz

Code

file_14083.txt

Credits

Molly Nicholas

Comments

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Halloween project: Blue Girl

Halloween project: Blue Girl

Things used in this project

Hardware components

Story

BlueGirl.fzz

Schematics

BlueGirl.fzz

Code

file_14083.txt

Credits

Molly Nicholas

Comments

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