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.

Click here to view the embedded video.

View the PDF

            

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.

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. 

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

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.

  

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…

Click here to view the embedded video.

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

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

  

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. 

    

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.

 

    

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

Click here to view the embedded video.

A collaboration with Paul Rothman and Steven Litt.

The steps
A marble rolls down a spiraling track, which then hits a LEGO turnstyle, which pulls a brake from under a LEGO cart’s wheel, which then rolls down a slanted board. The cart has a lit candle on the front, which burns a string holding down the spring on a toaster. The toaster then shoots another LEGO piece onto a mouse trap, which pulls away a stick of wood that is holding up a guillotine. The guillotine then flies down and through the egg, slicing it perfectly in half. A channel under the structure holding the egg directs all the yolk into the final container.

Iterations
Our original idea for the final step was to have a Dremel tool slice off the tip of the egg. The Dremel would be on from the beginning and would gradually move down towards the egg. This was done by balancing it on a pulley with a bucket of sand. The bucket had a hole at the bottom, which was blocked with a piece of cloth. The cloth would get pulled out when the mouse trap got triggered. This only worked a few times because the Dremel had to be lowered very slowly or else it would slip off the egg. When it did work, the shaft of the cutting tool would get caught in the egg causing the Dremel to slip off to one side. Also, this method resulted in a mist of egg yolk being sprayed all over the place, which was sort of disgusting.

We then proceeded with the guillotine idea, but now needed it to be lowered as fast as possible. We tried keeping the bucket of sand and using magnets connected to twine to break it off the pulley, but that was too unreliable. We finally opted for the support wooden stick solution, which worked every time.