Our project is a mechanical jellyfish whose tentacles scrunch as it bobs up and down. The top is a wire armature with fabric wrapped around it, and the tentacles are acetate plastic strips that have been hand cut and laser cut. Clear fishing line connects the tentacles and suspends the jellyfish from a stepper motor that controls its vertical movement. Some fishing line runs from the top of the jellyfish up to two ball bearings, the stepper motor, and a counterweight. The rest connects the tentacles together and is anchored to the bottom of the wooden frame structure. Pulling the string upwards pulls our tentacles upward, causing them to scrunch.
We were inspired by this youtube video and by the movements of real jellyfish. http://www.youtube.com/watch?v=JAULjWIwJBg
We wanted to create a puppet that would elegantly mimic the gestures of a jellyfish with only one motor. First we fabricated a small, non-motorized prototype to experiment with how to best execute the gesture of the tentacles, then worked on how to bring it to life with Arduino. Using a servo motor would have been easy, but we were turned off by the loud squeaky sounds that they make. We experimented with muscle wire as a means to pull our jellyfish up, but it was difficult because muscle wire only shrinks 3-5% of its length. Instead we chose to use a stepper motor, and went through several before we found one that was powerful enough to raise and lower the jellyfish. Adding the on/off switch was also a challenge because we were unfamiliar with the circuitry of the stepper motor. Luckily, we got a lot of great advice from Ali Momeni and Robb.

We went through several sketches before arriving at our final design.

Code:

#include 

// Map our pins to constants to make things easier to keep track of
int pushButton = 7;
const int pwmA = 3;
const int pwmB = 11;
const int brakeA = 9;
const int brakeB = 8;
const int dirA = 12;
const int dirB = 13;
boolean forward = true;

// The amount of steps for a full revolution of your motor.
// 360 / stepAngle
const int STEPS = 500;
int currentStep = 0;

// Initialize the Stepper class
Stepper myStepper(STEPS, dirA, dirB);

void setup() {
  // Set the RPM of the motor
  myStepper.setSpeed(8);

  // Turn on pulse width modulation
  pinMode(pushButton, INPUT); 

  pinMode(pwmA, OUTPUT);
  digitalWrite(pwmA, HIGH);
  pinMode(pwmB, OUTPUT);
  digitalWrite(pwmB, HIGH);
  // Turn off the brakes
  pinMode(brakeA, OUTPUT);
  digitalWrite(brakeA, LOW);
  pinMode(brakeB, OUTPUT);
  digitalWrite(brakeB, LOW);

  Serial.begin(9600);
}

void loop() {

  if (digitalRead(pushButton)==1){
    Serial.println ("steppin'!");

    if(forward){
      myStepper.step(1);
      currentStep +=1;
    } else {
    myStepper.step(-1);
    currentStep +=1;
    }

    if (currentStep == STEPS){
      forward = not forward;
      currentStep = 0;
    }
  }
}

Note: Fritzing does not have support for the Arduino motor shield we used.

Our project started as an idea to see how light could be altered by clear shapes moving around it. We wanted to have a series of gears that would turn and move around strings of clear shapes in interesting ways. One of the earlier problems we encountered was the positioning of the gears, which unfortunately made us reconsider the design and just put them along the top of the box instead of all over just so we knew they would work consistently. The next problem we had was simply being able to make at the gears turn with only one motor. Though we began developing a solution, it was brought to our attention that we would have probably needed another layer on top of our current one to hold everything in place and would need something stronger like a rubber band to rotate everything. Despite these mechanical issues, I do believe that we have made a satisfactory prototype of a light-based work especially when it is viewed in the dark. I am proud of the starburst effect that emits from the box due to the strands of clear shapes and I like that it almost looks like a water-reflected surface when the gears do rotate. Overall, I feel like while we had our share of construction issues while making this project, it was definitely not a waste and rather something that we learned a lot from with some level of success.

EMS documentation from Rosey Denton on Vimeo.

Our goal for this project was to give our automaton less than admirable human qualities juxtaposed against a desperate will to survive and be free. Our hopes were to capture the gesture of the struggle to free oneself from a straight jacket. As we head towards artificial intelligence with great advances in computing technology and science we began to question if artificial emotion will be developed as well. Is it possible to an intelligent computer to have emotional or mental sickness?

We created this automaton using two servo motors attached to laser-cut wooden framework and gears. It wears a hand-sewn straight jacket to constrain its motion. The figure is attached to a metal box with an on-off switch on the outside and all of the wiring, the Arduino, and the breadboard inside.

The automaton’s movement has three stages: frantic motion, reserved motion, and rest. The servo angles and delay times use a constrained randomized method to simulate struggle.

 

Photos:

   

 

Video:

[youtube http://youtu.be/-bNvmn04A_Q]

 

Fritzing diagram:

 

Code:

// less than and greater than signs messed up the code on this 
// blog post so I had to spell out "is less than" and 
// "is greater than"

#include Servo.h

Servo servo1, servo2;
const int buzzerPin = 4;
const int franticReps = 18;
const int reservedReps = 7;
int position;

void setup() {
  servo1.attach(8);
  servo2.attach(9);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  int m=0;
  // frantic motion
  while (m is less than franticReps){
    franticMotion();
    m++;
  }
  // reserved motion
  int n=0;
  while (n is less than reservedReps){
    reservedMotion();
    n++;
  }
  // rest
  delay(random(8000,10000));
}

void reservedMotion() {
  for(position=40; position is less than 140; position+=4) {
    // shoulders
    servo1.write(position);
    // elbows
    servo2.write(position);
    delay(30);
  }
  for(position=140; position is greater than 40; position-=4) {
    // shoulders
    servo1.write(position);
    // elbows
    servo2.write(position);
    delay(30);
  }
}

void franticMotion() {
  // shoulders
  servo1.write(random(20,60));
  // elbows
  servo2.write(180);
  delay(random(200));
  // shoulders
  servo1.write(random(120,160));
  // elbows
  servo2.write(0);
  delay(random(200));
}