Archive for the 6 Form & Motion Category

An Ordinary Table?

Posted in 6 Form & Motion on December 5, 2009 by melloko

For form and motion, I made a table an ordinary table. But, when the room is dark, the table transforms into a ghost! The ghost spins and stares at you with its glowing green eyes.

A photoresistor was used to sense the amount of light above it. When a shadow is cast over it, it turns on the LEDs and the DC motor. Look out hellokitty!

How it Works:

Materials Used:
1 DC Motor
2 Green LEDs
1 Photoresistor
Cardboard from an oreo box
A hellokitty doll
1 straw
1 napkin
Tape

Circuit Diagram

Arduino Sketch: Melissa_6TableGhost

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Nobody Puts a Finger on My Butterfinger

Posted in 6 Form & Motion on October 19, 2009 by Rohit

So one of my friends is obsessed with butterfingers. Like absolutely obsessed. Her vice, and the old slogan used by Butterfinger (remember the commercials with bart simpson…) tempted me to think up this idea for the Form and Motion assignment.

The idea is very simple: a security box that protects a butterfinger by attacking anyone trying to steal it. If an unsuspecting thief puts their hand in the box a spiked paddle swings down on to them. The owner knows that a secret switch on the side needs to be pressed to safely retrieve the Butterfinger bar.

The mechanism is fairly simple: IR sensor mounted on top that when tripped caused a servo-powered paddle to swing down. When a button on the side, powered by a 9V external power source, is held down a Green “Go” LED is lit and the Servo is disabled.

The box is made out of foamcore. The paddle is a dowel attached to foamcore with thumbtacks as spiked in the foamcore paddle. This paddle worked well because it was light however I would have liked the paddle to be even faster and believe that this might be in part because of the weight of the paddle. The light diffuser on the green LED is a ping pong ball and everything else is just stuck together with red electrical tape.

Some stuff to mention: In the video the paddle will go down when nothing appears to be in the way. This is mainly because the IR sensor was tilted a tiny bit which caused objects to interrupt it even though they weren’t directly in the box. Also you might notice that the butterfinger is an empty wrapper…the project took me longer than expected and I got a bit hungry 😛

Arduino Sketch in comment

Love & Hate Robot

Posted in 6 Form & Motion on October 19, 2009 by mehrdadgh

For the assignment in form and motion, I built a robot which is called hate and love robot. Robot has been assembled on a chariot made of basswood, two wheels in rear and a sliding wheel in front. This robot is basically uses two IR sensor as input device and controls its two DC motors using input information. The input of left sensor controls right motor and the input of right sensor controls left motor. The following image is an illustration:

braitenberg

The robot has a push button on it that send an input to arduino. Using it user can change robot mode. The uploaded code controls arduino so that for odd pushes of push button robot goes on love mode, and for even pushes robot goes on hat mode.

In love mode when a IR sensors detects an object in close distance the related motor generate torque so robot moves toward the object. In hate when a IR sensors detects an object in close distance the related motor stop generating torque so robot moves away from the object for the other motor is generating torque. (Refer to the following book: http://books.google.com/books?id=7KkUAT_q_sQC&dq=braitenberg+vehicles)

DSCN6670

DSCN6672

DSCN6671

Watch the story of this robot:

Dribbling Robot

Posted in 6 Form & Motion on October 18, 2009 by ellenwu

I made a dribbling robot that dribbles faster as a defender approaches. An IR sensor is used to detect the distance of a defender. The signal then determines the speed of a DC motor. Rotary motion of the motor is converted to a rather linear one inspired by a clockwork sping squirrel tail that i saw at shadyside varieties. A similar mechanism called quick return can be found on fly pig.

The circuit and code are very simple in this case, but it took me a long time to tweak the material, shape and position to make the whole thing functions smoothly. I used basswood and sponge tape to attach to the motor because they provide more friction while i used my chicago CTA transit card and acrylic rod to make the quick return unit because they allow rapid spinning, and at the same time, are strong enough to stand the centrifugal force.

Motor was a pain. I tried one gear motor (9V) which ran too slowly, one fan motor (12V) which i had a hard time connecting all the batteries, and one regular motor (3V) which i went with. Whichever took me a long time to test, and i almost burned my arduino once… i was to use a styrofoam ball or pingpong ball, but they are both too heavy for my tiny parts, so i ended up just drew a flat basketball.

Finally, i illustrated my circuit. hopefully it’s more clear than the photos!

circuit02

CIMG9754

CIMG9756

CIMG9760

Arduino Sketch: Wu_dribbling robot

JumpBox

Posted in 6 Form & Motion on October 17, 2009 by lukekambic

It’s a cubic foamcore box about 5 inches tall with a solenoid in the bottom and a long-range Sharp IR sensor on one side. The program sends a shaped pulse to the solenoid coil whenever the sensor detects a rapid decrease in distance. The solenoid has small weights attached to its core and the rapid shift in mass makes the box jump slightly in the opposite direction. The falling side of the pulse is a stepped ramp to make the spring-powered return of the solenoid slower, which keeps the box from moving back in the opposite direction.

This would work with just a spring and weight and a servo to contract it, but a solenoid system is mechanically simpler and allows easier control of the motion of the weight. Three 9 volt batteries in series can’t supply enough current to contract the solenoid, so I attached 14,100 uF worth of capacitors across the supply rails. The time between pulses is enough for them to recharge and deliver the next current pulse. The output is switched with a MOSFET. I didn’t have a logic-level MOSFET on hand, so I stepped up the Arduino output with a bipolar transistor to drive the FET.

It only jumps about 1/8” at the moment. It needs larger weights on the solenoid, and experimentation with roller wheels and unusual surfaces is in order.

Sketch:  <a title=”Arduino Sketch: Luke_Form_Motion” href=”http://code.arc.cmu.edu/~cheng/uploads/Luke_Form_Motion.pde&#8221; target=”_blank”>Luke_Form_Motion</a>

Schematic (this file also includes schematics for the 3rd and 4th assignments): Luke_Schematics_3,4,6

6. Bad Dog

Posted in 6 Form & Motion on October 17, 2009 by Maria Freitas

BadDog

Denzil Ferreira – Assignment 6 – Vigilant alarm!

Posted in 6 Form & Motion on October 17, 2009 by Denzil Ferreira

I’ve connected a servo motor and an IR sensor to the arduino to detect motion. The servo makes a dummy made of clay move from side to side, like as if it is scanning the horizon. Once motion is detected, the LED’s blink, like in an alarm.

Arduino Sketch: DenzilFerreira_A6