Difference between revisions of "Msc1G2:Student4"

Prototype assembling

1st silicone prototype for pneumatic actuators

2nd silicone prototype for pneumatic actuators

Simulation

To get the geometry right of as well the prototype and the 3D model we did several tests in Abaqus. To be able to bend up the triangles, the geometry should have a proper relation in height and weight, because the momentum of the bending force (M = F * a) is stated by determined by the height of a triangle side. Upper left shows a constellation of several triangles in silicone, the upper right an earlier version. The bottom left is a simulation of the very first prototype as seen above. On the bottom right the material is changed from silicone to aerogel silicone, this material has small air bubbles embedded in the material and is therefore way lighter than traditional silicone. Although the Youngs modulus and shear modulus have a negative effect on the bending behavior, this material can because of the weight be interesting to research for the interactive architecture practice.

Setup and arduino code

The swarmscape prototype is controlled by a technical board that reads information and tell the prototype how to react. The board is assembled with simple, low pressure aquarium pumps. These pumps are controlled by solenoid valves which are connected to the silicone structure. To regulate the 24 volt valves, two relay boards and 8 relays are mounted to the board, which are also connected to a Arduino Mega. A second electronic circle with a diode is embedded to prevent short circuits caused by the fall time of the electro magnet (see Setup and arduino code). Additionally, three pressure sensors are connected to the micro controller to process the information to bend up the prototype.

The code for the prototype needed to be sure that the air chambers at the hinges never get too much pressure, that the sensors work independent of one each other and that the controls are as intuitive as possible. This is achieved by defining the code for several states each sensor can be in accompanied with a timer library. A hinge inflates on the input of a pressure sensor. As long as the sensor is pressed it stays inflated, but when released it stays in position for a time defined by the pressure that is applied. After staying inflated for a while the code goes through a deflation part to be sure the chambers never get too much pressure. Eventually the sensor becomes idle again, waiting for pressure.

//sensor.h defenition (library used instead of void)
struct Sensor;

Sensor nextState(Sensor);

// Arduino code for Swarmscape prototype 2015-01-26
// Setup: FSR pressure sensors + array outputs linked to electronic valves

#include "sensor.h"
#include <TimerOne.h>

// Setting constants
int ledPin = 13;
int SENSOR_THRESHOLD = 40;
int SENSOR_TIMEOUT = 50;
int DEFLATE_TIMEOUT = 70;
int PRESSUREMAP_LOW = 0;
int PRESSUREMAP_HIGH = 750;
int MEASURE_TRESHOLD = 7;

// Building the structure
enum sensorState {
  set1,
  set2,
  idle,
  activated,
  measure,
  released,
  timed_out,
  deflate
};

struct Sensor {
  sensorState state;
  int pin;
  int time;
  int pressure;
  int out_pin;
  int defl_pin1;
  int defl_pin2;
};

Sensor sensor1 = {set1, A0, 0, 80, 12, 11, 14};
Sensor sensor2 = {set1, A1, 0, 80, 9, 7, 18};
Sensor sensor3 = {set1, A2, 0, 80, 5, 3, 22};


void setup() {
  Serial.begin(9600);
    
  pinMode(sensor1.pin, INPUT);
  pinMode(sensor2.pin, INPUT);
  pinMode(sensor3.pin, INPUT);
  
  pinMode(sensor1.out_pin, OUTPUT);
  pinMode(sensor2.out_pin, OUTPUT);
  pinMode(sensor3.out_pin, OUTPUT);
  
  pinMode(ledPin, OUTPUT);
  
  pinMode(sensor1.defl_pin1, OUTPUT);
  pinMode(sensor1.defl_pin2, OUTPUT);
  pinMode(sensor2.defl_pin1, OUTPUT);
  pinMode(sensor2.defl_pin2, OUTPUT);
  pinMode(sensor3.defl_pin1, OUTPUT);
  pinMode(sensor3.defl_pin2, OUTPUT);  
  
  Timer1.initialize(50000);         // initialize timer1, and set a 1/2 second period
  
  Timer1.attachInterrupt(callback);  // attaches callback() as a timer overflow interrupt
  
  Serial.println("Start: ");
  Serial.print("sensor1: ");
  Serial.print(sensor1.state); Serial.print(' ');
  Serial.print(sensor1.pin); Serial.print(' ');
  Serial.print(sensor1.time); Serial.print(' ');
  Serial.println(sensor1.out_pin);
  Serial.print("sensor2: ");
  Serial.print(sensor2.state); Serial.print(' ');
  Serial.print(sensor2.pin); Serial.print(' ');
  Serial.print(sensor2.time); Serial.print(' ');
  Serial.println(sensor2.out_pin);
  Serial.print("sensor3: ");
  Serial.print(sensor3.state); Serial.print(' ');
  Serial.print(sensor3.pin); 
}


void callback() {
  sensor1 = nextState(sensor1);
  sensor2 = nextState(sensor2);
  sensor3 = nextState(sensor3);
  
  Serial.print("State 1: ");
  Serial.print(sensor1.state);Serial.print(";");
  Serial.print(sensor1.time);
  
  Serial.print("State 2: ");
  Serial.print(sensor2.state);Serial.print(";");
  Serial.print(sensor2.time);
  
  Serial.print("State 3: ");
  Serial.print(sensor3.state);Serial.print(";");
  Serial.print(sensor3.time);
  Serial.print("\n");
  
}

void loop()
{
  // your program here...
}



Sensor nextState(Sensor sensor) {
  Sensor nextState = {sensor.state, sensor.pin, sensor.time, sensor.pressure, sensor.out_pin, 
sensor.defl_pin1, sensor.defl_pin2};
  boolean pressed = analogRead(sensor.pin) > SENSOR_THRESHOLD;  
  
  switch (sensor.state) {
// Setup state
    case set1:
      digitalWrite(sensor.out_pin, 1);
      nextState.state = set2;
      nextState.state = idle;
      break;
      
    case set2:
      nextState.time ++;  
      if (sensor.time > 50) {
      digitalWrite(sensor.defl_pin1, 0);
      digitalWrite(sensor.defl_pin2, 0);
      nextState.time = 0;
      nextState.state = idle;
      }
      else {
        nextState.state = set2;
      }
      break;
// Idle state
    case idle:
      nextState.time = 0;
      if (pressed) {
        nextState.state = measure;
      } else {
        nextState.state = idle;
      }
      break;
// Measurementstate
    case measure:
        nextState.time++;
        if(sensor.time > MEASURE_TRESHOLD);
          digitalWrite(sensor.out_pin, 0);
          sensor.pressure = analogRead(sensor.pin);
          nextState.time = 0;
          nextState.state = activated;
        }
        else {
          nextState.state = measure;
        }
      break;
// Activated state
    case activated:
      if (pressed) {
        nextState.time ++;
      } else {
        nextState.state = timed_out;
      }
      
      if (sensor.time > SENSOR_TIMEOUT) {
        nextState.state = timed_out;
      }
      
      break;
// Released state (stays up)
    case released:
      digitalWrite(sensor.out_pin, 1);
      nextState.time++;
      if(sensor.time > map(sensor.pressure, 0, 1024, PRESSUREMAP_LOW, PRESSUREMAP_HIGH)) {
        digitalWrite(ledPin, 0);
        nextState.time = 0;
        nextState.state = deflate;
      }
      else {
        digitalWrite(ledPin, 1);
        nextState.state = released;
      }
      break;
// Time-out state      
    case timed_out:    
      digitalWrite(sensor.out_pin, 1);
      if (pressed) {
        nextState.state = timed_out;
      } else {
        nextState.state = released;
      }
      break;
// Deflate state      
    case deflate:
      nextState.time++;
      digitalWrite(sensor.defl_pin1, 0);
      digitalWrite(sensor.defl_pin2, 0); 
      if (sensor.time > DEFLATE_TIMEOUT) {
        digitalWrite(sensor.defl_pin1, 1);
        digitalWrite(sensor.defl_pin2, 1); 
        nextState.state = idle;      
      }
      else {
        nextState.state = deflate;
      }
      break;
    default:
      break;
  }
  return nextState;
}

Documentation

• 

  Arduino setup prototype2

• 

  Origami folding patterns