Tag Archive for 'mechanisms'

The Zoeprojectoscope

The Zoeprojectoscope is a mechanical toy designed to teach kids the main concepts of frame-by-frame animation.¬†Animation is a fascinating concept, especially for kids who watch a lot of it. It’s always exciting to understand how the shows they watch are made.

How it works

  • Each frame is a piece of acetate which is drawn on.
  • The acetate is sandwiched between two clear pieces of acrylic and placed in the wheel, which holds slots for 12 frames.
  • To animate the drawings, the user turns the crank, which makes the wheel turn, and places the frames in front of the optics in the right order.
  • A light shines through each frame at the right moment, powered using the energy generated by turning the crank.
  • A system of gears attached to the crank spin a motor at high speed, generating enough electricity to power a set of LEDs.
  • A contact switch is positioned in front of the wheel so that the light is only turned on when each frame is perfectly aligned with the optics. This simulates the shutter from a real projector.
Next Steps
  • Fix the optics to make the projection work
  • Add legs on the side to make the production surface usable
  • Make the whole thing lighter by using a thinner wheel
  • Add a base to increase stability

View the PDF

Zoeprojectoscope Prototype

Here are some pics of the Zoeprojectoscope being built. All the pieces were laser cut and then assembled using acrylic glue. Everything fit surprisingly well together, and I added a layer of Teflon tape to pieces that required a tighter fit.

IMG_2678 IMG_2698 IMG_2676 IMG_2702 IMG_2714 IMG_9635 IMG_2712 IMG_9660 IMG_9661 IMG_9671 IMG_9672 IMG_9673 

There is still work to be done. I have to recut the lens case and also cut a bunch of stopper pieces to attach the gears and wheel to the shafts, which is something I completely forgot about.

Zoeprojectoscope Proposal

A more thought-out proposal of my zoetrope/projector…


The Zoeprojectotrope is a hybrid between a projector and a zoetrope. It is a toy designed to teach kids the main concepts of animation. 

Each frame is a piece of acetate which is drawn on. A recession in the frame of the device can be used to position two frames on top of one another, to ensure that the movement between them is fluid. The acetate is then sandwiched between two clear pieces of acrylic and placed in the wheel, which holds slots for 12 frames. To animate the drawings, the user turns the crank, which makes the wheel turn, and places the frames in front of the optics in the right order. 
zoetrope-right zoetrope-left

The optics at the front follow the same principle as an overhead projector. A light will shine through the frame, and the image will reflect off a mirror on the other side, get enlarged through the lens, and finally get displayed on the wall. 

The light will be powered using the energy generated by turning the crank. A system of gears attached to the crank will spin a motor at high speed, generating enough electricity to power a set of LEDs. A set of contact switched will be positioned around the wheel so that the light is only turned on when each frame is perfectly aligned with the optics. This will simulate the shutter from a real projector. 

The Zoeprojectotrope will be entirely made out of acrylic sheets. The sheets will be laser cut because of the complexity of the shapes and because of the high level of precision required for the gear system and the optics. The lens and the mirror in the optics will be made out of glass.

View the PDF

Ball and Cup, the Spring Version

Here is the spring contraption Stella and I built for the Mechanisms assignment. The object is to get the LED into the cup by hammering the end of the stick down. The spring then pushes it back up, propelling the LED into the air.

DSC00078 DSC00076
DSC00075
DSC00073

DizzyCat User Testing

Here are some images of the completed object. It is a little bulkier than I originally intended, mainly to accommodate the 4 AA batteries. My original idea of powering the whole circuit using a coin cell battery did not fly because it does not supply enough current.

IMG_0079 IMG_0094 IMG_0107 IMG_0098

The base is made out of a thin custom cut piece of wood. The shell is a plastic dome covered with some fur I got from skinning a teddy bear. The dome offers good protection for the electronics on the top of the base, but I still need to find a way to guard the motor and batteries at the bottom.

IMG_0102 IMG_0099 

I took DizzyCat up to Montreal with me to test it out with my cat before working on the collar. I was a little worried that she would not be too crazy about it since it is a little slow and noisy. As can be seen in the following video, I was right to worry. Back to the drawing board…

DizzyCat Proposal

DizzyCat is a toy designed to make my cat active again, as she is getting fatter every day and needs to exercise. I unfortunately cannot play with her on a daily basis since moving to New York, and since she is alone for the most part of the day, she spends all her time eating and sleeping.

DizzyCat is a little toy on wheels that has four basic behaviours:

  • If the cat is not moving, it slowly creeps towards her.
  • If the cat is moving towards the toy, it moves away from her.
  • If the cat is moving away from the toy, ¬†it moves towards her.
  • If the toy bumps into something, it moves in the opposite direction.

The idea is to make an autonomous toy that will keep her entertained for hours. As any cat owner will tell you, it is very difficult to find a good toy because cats expect whatever they are playing with to react to them, either by fighting back or running away. A weight at the end of a string just does not cut it because it quickly becomes boring, even for an animal. Any good cat toy needs to be interactive; it needs to taunt the cat to play with it and offer it some sort of challenge.

Special attention will be brought in the design to make DizzyCat as quiet as possible, as I have noticed that my cat tends to stay away from noisy things. It should also be built strong as it will probably be thrown around a lot, but should feel soft like a small, helpless animal.

The body of the toy will be made out of blue foam, because it is a very light and fairly solid material. This will be covered with a furry or feathery material so that it feels good to the bite. The moving mechanism will consist of a battery-powered DC motor attached to the wheels, using a system of gears to achieve appropriate speed and torque. The behaviours will be achieved by simply turning the motor in either direction using an H-bridge. Proximity between the cat and DizzyCat will be measured using XBee modules. One XBee will be placed on DizzyCat, and the other will be attached to a custom cat collar. An Arduino board will take care of the logic, polling the distance between the XBees, judging if both objects are getting closer or futher away from each other, and choosing a direction and speed to spin the motor based on this information.

View the PDF

Zoetrope Early Tests

After presenting my zoetrope toy idea to class last Tuesday, I realized that I had completely forgot to add a lens to the design. A lens would be necessary for the projection, so that the image on the wall is bigger than 2″ wide. I ran some quick tests today to see what sort of setup is possible.

I had many lenses to try: an acrylic half-sphere from Canal Plastics and a bunch of lenses Matt pulled off a projector. 

IMG_1546 IMG_1553 

I made a tube out of sheet metal and placed a piece of acetate with a drawing on it between two pieces of acrylic at one end. I attached a super-bright LED to the end of a wooden stick, which I put in the tube from the other end. Using the stick, I could move the light back and forth to see what  distance would work best. 

IMG_1551 IMG_1552 IMG_1548 IMG_1547 

Only one lens worked properly, but my whole setup was a bit too loose to calculate any distances. I’ll have to build a second prototype where the lens, drawing, and light are all mobile to get more concrete results.

 IMG_1535

Mousetrap Race Car

Here is the mousetrap race car I built with Karla. The frame is built out of LEGOs, the back wheels are an electric wire spindle cut in two, and we used a rubber band connected to the mouse trap as the engine.

IMG_1529 IMG_1531 IMG_1532 IMG_1530 

It goes pretty fast, but we over-wound the rubber band for the official race and came out in 3rd place.

LEGO Crane

Here is our awesome LEGO crane. As can be seen in the pictures, we went for the version with the electric motor.
IMG_1515 IMG_1518

Rube Goldberg Machine

The object the Rube Goldberg machine was to crack an egg in at least five steps, ending up with more than half the egg and less than half the shell in the final container. As can be seen in the video, we managed to get most of the egg and no shell at all!

A collaboration with Paul Rothman and Steven Litt.

Continue reading ‘Rube Goldberg Machine’