retrointerfacing

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Archive for the ‘fablab’ Category

Hexapod in the press

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IEEE Pervasive Computing magazine recently had an article featuring the hexapod..

Written by edwin

February 18th, 2012 at 2:36 pm

TechFest 2012

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Together with PLANETART and FullFormFreedom invited to show some of the robots at the TechFest 2012 festival in Mumbai, India.

img_8697

Written by edwin

January 22nd, 2012 at 12:31 am

Posted in Robotics, expo, fablab, rapid prototyping

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MakerBot Thing-O-Matic

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Ok, one could argue that it is cheeting, but before the PrinterPrinter is ready, I thought of taking a shortcut by building a makerbot first. The Thing-O-Matic works right out of the box (and about 200 m3×16 socket screws later):

Written by edwin

March 21st, 2011 at 4:05 pm

PrinterPrinter @ Refab session

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During Fab6, the international fablab conference, the printerprinter has been presented during a session on ‘refab’ at the fablab Amersfoort. Results of the workshop, presentation slides etc. can be found on the wiki. The workshop resulted in a set of ‘house rules’ for refab in fablabs (but they equally apply to work in whatever lab you’re making stuff):

  • bring your own stuff, take your own waste
  • be efficient with your design and materials (limit your waste)
  • be efficient with your tools (hand tools are handy too)
  • make it modular, upgradable, repairable, recyclable!
  • make sure you know the material you are working with
  • contribute your errors and mistakes (document!)
  • mark what your thing’s made of (document!)
  • reuse what you can find!
  • build stuff to last

Written by edwin

September 13th, 2010 at 2:33 pm

Posted in fablab, fabrication

Tagged with ,

Repstrap using HP840c’s

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With the StarLC10 matrix repstrap ending up as pizza plotter, a start has been made building a new 3D machine using only the parts of 3 HP deskjet 840c printers.

r0013937

The printers contain many useful parts, the casing is made almost entirely out of ABS (printing material, hurray!)

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Especially the sliders come in nice, rectangular frame’s which make mounting them easy. For the first tests a frame has been assembled using standard aluminum X-beams (boikon).

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Using the cleaner bin (which normally brushes and seals the cartridge) a Z-axis has been made which has at least 8cm of travel:

r0013947 r0013958 r0013959

Arduino-based control of a DC motor using incremental encoder and PID is not much more difficult than controlling a stepper motor. See the wiki for full documentation.

void setup(){
  int oldposition;
  Serial.begin(9600);
  attachInterrupt(0, encoder, RISING);
  pinMode(10,OUTPUT);
  pinMode(12,OUTPUT);
  setMotor(-150);
  delay(50);
  while(position!=oldposition)  {
    oldposition=position;
    delay(50);
  }
  setMotor(0);
  position=0;
}
void loop(){
if(millis()>time+1)
{
  float setpoint = 1000+400*sin(n/200)+200*sin(n/50); // 1890 positions
  float error = setpoint - position;
  setMotor((int)(limit((Kp*error + Kd*(error-oldError) + limit((Ki*sumError),antiWindup)),255)));
  oldError = error;
  sumError+=error;
  n++;
  time=millis();
}
}
void encoder() {// encoder service routine
  if (digitalRead(4)>0) position++;
  else position--;
}
void setMotor(int value){ // set PWM of motor, value may range from -255 to 255
  if (value>=0)   {
    digitalWrite(12,LOW);
    analogWrite(10,value);
  }
  if (value<0)   {
    digitalWrite(12,HIGH);
    analogWrite(10,value);
  }
}

next up: including the extruder head, interfacing, making connections, shredding abs, making a scrap-2-3mm-wire extruder system, etc.. etc…

Written by edwin

August 22nd, 2010 at 9:28 pm

Posted in fablab, fabrication

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18-servo walker

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New A4 flat-kit design: a 18-servo 6-legged hexapod. It does not walk (yet) but servo control works and the mechanics look good:

r0013970

All parts can be cut from a single A4 sheet of acrylic glass. Other parts include 18 miniature servo’s (selling for 5EUR as TopLine mini-servo ES-05 JR (at Conrad Electronic)) and an ottantotto board

r0013969

The servo’s are controlled using a simple soft-servo library (for the timebeing) which can be found here.

Written by edwin

August 22nd, 2010 at 8:53 pm

Posted in Arduino, Robotics, fablab, fabrication

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Flatpack Walker with Sensor

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As presented for the first time on FAB6, using a Sharp gp2y0a02 sensor the flatpack-walker just got a little bit smarter. As long as the distance sensor is triggered, the robot walks backwards.

flatpack

The code is still pretty simple:

// avoid obstacles using Sharp G2P sensor on Analog 0
#include <Servo.h>
Servo frontservo,backservo;
char walkpattern[] = {60,100,100,100,100,60,60,60};
void setup(){
  frontservo.attach(9);
  backservo.attach(10);
}
void loop(){
  for(int n=0;n<4;n++){
    if(analogRead(0)>500){
      frontservo.write(walkpattern[2*n]);
      backservo.write(walkpattern[(2*n)+1]);
    }
    else{
      backservo.write(walkpattern[2*n]);
      frontservo.write(walkpattern[(2*n)+1]);
    }
    delay(200);
  }
}

Written by edwin

August 22nd, 2010 at 7:40 pm

Posted in Arduino, Robotics, fablab

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