I made a horrifying ghoul for halloween, using a box, leds, servos, ping pong balls, vampire teeth and an arduino.

There is a photoresistor in its nose, which detects the amount of light in the environment. When the lights are off, the servos twitch at random angles to move the eyes and mouth. I used the autotune function from the circuit 6 in the SIK book so I didn’t have to calibrate it in different lighting environments.

Video of it in action:

[flickr video=8148307250 secret=351dfe9dff w=400 h=225]

Here’s a diagram of my circuit:

and my code:

#include 
Servo servo1, servo2, servo3;  // servo control object
int pos1 = 0;
int pos2 = 0;
int led1 = 11;
int led2 = 6;
int input = 3; 

int period = 500;
int sensorVal = 0;
unsigned long lastDidItTime = 0;
int high = 0, low = 1023;

void setup()
{
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(input, INPUT);
  servo1.attach(9);
  servo2.attach(10);
  servo3.attach(3);
  Serial.begin(9600);
} 

void loop() {
  sensorVal = analogRead(A0);
  autoTune();
  unsigned long presentTime = millis();
  Serial.println(sensorVal);
  if(sensorVal > 0){  
    unsigned long elapsedAmount = presentTime - lastDidItTime;
    if (elapsedAmount > period){
      pos1 = random (50, 140); 
      pos2 = random (30, 70);
      servo1.attach(9);
      servo2.attach(10);
      servo1.write(pos1);
      servo2.write(pos1);
      digitalWrite(led1, HIGH);
      digitalWrite(led2, HIGH);
      lastDidItTime = presentTime;
      servo3.write(pos2);
    }
  }
  else {
    servo1.write(90);
    servo2.write(90);
    servo3.write(90);
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
  }

}

void autoTune()
{
  if (sensorVal < low)   {     low = sensorVal;   }     if (sensorVal > high)
  {
    high = sensorVal;
  }

  sensorVal = map(sensorVal, low+30, high-30, 0, 255);
  sensorVal = constrain(sensorVal, 0, 255);

}

I decided to make a mutant Baby Pumpkin Monster in celebration of Hallowuino. If you leave ze monster alone, it is a peaceful jack-o-latern. But, if you push his button, he will seek revenge. His eyes will switch from a yellow glow to flashing red, and his arms will swing with the intent to attack you.

If I were to put this piece in gallery, there would be a spooky night background behind it, and a metal link chain would be wrapped around it making it look as if it is being restrained. There would also be a sign next to it that reads: “Beware of Monster: DO NOT PUSH HIS BUTTON”. For some reason it is a natural instinct for people to rebel and press the button in this case, thus making the piece interactive.

Here is the video of my monster:

[flickr video=8148308678 secret=4d30222477 w=400 h=225]

Here is the Arduino Fritzing diagram of my monster:

Here is the code for my monster:

#include   // servo library
Servo servo1;  // servo control object
Servo servo2;  // servo control object

int redLED = 12;
int yelLED = 13;
const int buttonPin = 2;

//-----SCARY SETTINGS-----
int redEyeFlashTime = 75;
int motorCalls = 4;

void setup()
{
  pinMode(redLED,OUTPUT);
  pinMode(yelLED,OUTPUT);

  pinMode(buttonPin, INPUT);

  servo1.attach(9);
  servo2.attach(6);

  normalMode ();
}

void loop()
{
  //-----Check Button State-----
  int  buttonState = digitalRead(buttonPin);

  if (buttonState == LOW)
  {
    scaryMode();
  }
  else
  {
    normalMode();
  }
}

void normalMode ()
{
  digitalWrite(redLED, LOW);
  digitalWrite(yelLED, HIGH);
}

void scaryMode ()
{
  //-------SERVO CODE-------
  for(int i = 0; i < motorCalls; i++)
  {
    //int position1 = constrain(random(0, 180), 0, 180);
    int position1 = constrain(random(0, 180), 110, 180);
    servo1.write(position1);  // Move to next position

    int position2 = constrain(random(0, 180), 110, 180);
    servo2.write(position2);  // Move to next position

     //-------LED CODE----------
    digitalWrite(yelLED, LOW);
    digitalWrite(redLED, HIGH);

    delay(redEyeFlashTime);

    digitalWrite(redLED, LOW);

    //-------SERVO CODE-------
    position1 = constrain(random(0, 180), 0, 70);
    servo1.write(position1);  // Move to next position

    position2 = constrain(random(0, 180), 0, 70);
    servo2.write(position2);  // Move to next position

    delay(redEyeFlashTime);
  }
}

 
#include  

// Create a servo "object", called servo1. Each servo object
// controls one servo (you can have a maximum of 12):

Servo servo1;
const int flexpin = 0; 
const int motorPin = 5;

void setup() 
{   
  Serial.begin(9600);
  servo1.attach(9);
  pinMode(motorPin, OUTPUT);
} 

void loop() 
{ 
  int motospeed;
  int flexposition;    // Input value from the analog pin.
  int servoposition;   // Output value to the servo.

  // Read the position of the flex sensor (0 to 1023):

  flexposition = analogRead(flexpin);

  servoposition = map(flexposition, 760, 938, 0, 180);
  servoposition = constrain(servoposition, 0, 180);
  motospeed = map(flexposition,760,930,0,255);
  servo1.write(servoposition);
  analogWrite(motorPin, motospeed);

  //serial sensor info
  Serial.print("sensor: ");
  Serial.print(flexposition);
  Serial.print("  servo: ");
  Serial.println(servoposition);
  delay(20);  // wait 20ms between servo updates
}

This was an exciting project.  I used one flex sensor, one motor and a servo.  The action is activated by "hurting the mummy" - this means bending him in places he does not want to bend.  This upsets the Mummy and as you hurt him, he begins to writhe in pain - flailing his arms as his head spins.

I decided to make a creepy doll arm “graveyard” where the ground is made of (fake) fur. Three plastic doll arms are connected to Servo motors, and they rotate at a speed controlled by a sliding potentiometer. If the potentiometer is at its lowest value, the arms twitch instead of rotating.

Photo:

Video:

[flickr video=8148299589 secret=8463568572 w=400 h=225]

Fritzing diagram:

Code:

 
#include Servo.h 
// WordPress will not allow the less than / greater than 
// symbols that normally go around Servo.h 

Servo servo1, servo2, servo3;
const int sensorPin = 0;
int sensorValue, delayTime, position;

void setup() {
  // servos are connected to pins 7, 8 and 9
  servo1.attach(9);
  servo2.attach(8);
  servo3.attach(7);
  Serial.begin(9600);
}

void loop() {
  sensorValue = analogRead(sensorPin);
  Serial.println (sensorValue); 
  moveServos();
}

void moveServos() {
  // rotate to 180 degrees
  for(position = 0; position = 0; position -= sensorValue) {       
    changePositions();         
  }
}

void changePositions() {
  // test for the sensor value as servo rotates to see if it should 
  // change speed
  sensorValue = analogRead(sensorPin);
  // map potentiometer values to speeds 1-7
  sensorValue = map(sensorValue, 0,900, 1,7);
  servo1.write(position);
  servo2.write(position);
  servo3.write(position);
  // test for delay time as servo rotates to see if it should 
  // switch to twitching
  delayTime = testDelayTime();
  delay(delayTime);  
}

int testDelayTime() {
  // if the potentiometer value is less than 2, switch to the 
  // twitching motion by setting delay time to zero
  if (sensorValue < 2) {
    delayTime = 0;
  }
  else {
    delayTime = 20;
  }
  return delayTime;
}