In this meeting we discussed the following:

1. belt system for the student running around the computer center. We figured out the approximate length of the belt for our system. We selected possible driving gear and pulleys.

2. main transmission in order to translate the motion from main shaft to all the other gears parallel to the bottom plate. This will be done using either one set of bevel gears right near the main shaft or two sets of bevel gears to reduce torque (one of two snail cams on the right side, one for belt system and the other snail cam on the left side).

3. sizes for gears so that the timing of everything makes sense. we decided that we want the student to take 15seconds to make one revolution. based on that criterion, we talked about possible sizes for snail cam gears and other transmission gears - but this wasn't fully finished.

some pictures from the meeting:

We have preliminary drafts of two of our tougher mechanisms:

1. Popping out and popping back in of characters hiding behind doors: Initially we considered a rack-and-pinion system with a portion of the teeth removed from the gear, with a tensioned spring pulling on the base on which the moving character is mounted. The toothed portion of the gear would pull the character back behind the door against the restoring force of the spring. Then, when the smooth portion of the gear contacted the rack, the rack would get pulled forward quickly by the spring, making the character pop out.

The above idea has been revised, as we have discovered drop cams (a.k.a. snail cams). This mechanism is simpler, although hard to describe in words - see our External Links page for the link to an animation of a snail cam in action.

2. The belt-driven (non-circular) path of the “main character” who will be running around the computer center. We will use a timing belt driven by four gears; a path cut in an acrylic sheet will help to guide the character. We will laser-cut gears for our prototype this week; we intend to eventually buy gears and a timing belt from SDP-SI. A link to their website can be found in our External Links section as well.

I decided to take a look at some of the mechanical systems that we will need to get this automata working. The rough sketches I drew are included below. What I am thinking is that we use a tank tread kit that is available on the internet. The issue that may come up is that it might need to be supported by more than just the placement wheels and the driving gears. By using some tread system, we are allowed to make the characters movement more realistic, rather than a circle or a line.

I also looked into a method of having the elements “pop” out of doors. I figured we could have a spring bring back the figure, and then somehow get it to release it. I believe the tricky part of this would be to have the pop timed with the character walking past the doors. Maybe we could have the spring lock and somehow not wind anymore until the character gets close, then have a trigger release the character and have the gears then wind the spring back up.

We finalized our design with Professor Lima; we had to simplify it a lot. We removed the moving scene of Keith and the computer virus fighting and instead we're going to have the computer virus pop out of that door to Keith's office and try to attack the student. The battling artist and engineer have been removed for space reasons. We've still got Professor Cusack and Professor Lent, as well as a malfunctioning printer. So three moving things other than the student (virus, Lent, Cusack). Professor Lima suggested having the music box paper visibly being pulled through the printer; we're going to try to make that work.

For this week we need to work on our most complicated mechanism, which is definitely getting the student to move in a non-circular track. So we need to brainstorm that mechanism and have detailed drawings for Wednesday. A week from Friday we have to have a prototype of that mechanism made and ready for a demo. We found some tank treads from battle robots online that we think will work - we can have the tread pulled by rollers in a relatively complex path. The issues so far with this are (a) can we have a tread sort of “hanging,” because the rollers will be oriented vertically, (b) how do we attach the figurine to the tread securely, and © can we identify a specific tread that we can buy and make work?

Last week, the group reached the idea of a Cooper student (possibly Greg) circling around in the computer center while getting approached or attacked by three obstacles, one of which is Prof. Cusack with a samurai sword. Over the weekend, each group member were to think about what those obstacles should be, how the room should be set up, and what kinds of motions the character should have. Today we met up as a group to discuss our ideas. Each of us brought our own drawings and presented our ideas to the other members.

In the end, we picked several components from the individual drawings and combined them in a final drawing. The final drawing is shown below. The general idea of the automaton is to illustrate various aspects of a Cooper student’s life. In the center of the “room,” the student is circling around a station of computers. Behind the student, a Peter Cooper head is chasing the student, following the same track. On the left side of the room, there is a clear wall showing a hallway. In the hallway is a duel between an engineering student holding rulers and protractors and an artist student holding paintbrushes. The will move back and forth in linear motion. On the right side of the room, there is a row of professor offices. When the student passes this side of the room, Brian Cusack will pop out holding a samurai sword while Chris Lent pops out with a tweet-bird on his shoulder. These motions will most likely be executed using a spring mechanism. On the back side of the room, Keith is getting attacked by a computer virus. Lastly, a steel mesh surrounds the automaton to present the new Cooper building.