CMU's Spring Carnival is similar to Homecoming for other colleges. One of the main attractions of Carnival is Booth.

Student organizations build multi-story structures that fit with a chosen theme. In 2025, the overall theme was Hollywood. 

Each individual booth chose a distinct movie theme. Inside each booth there are interactive games and elaborate decorations of their distinct theme.

Our Booth's theme was Jurassic Park and our interactive game was a story driven puzzle.

The end of the attraction must feature a dinosaur jump scare with different expressions based on win or loss.

Enclosure:

• Fits in a box size: 56cm x 100cm (LxW)

• Fits through a window sized: 6.5in (W)

• User Experience requested: Centered at the wall at 110cm high.

• Dinosaur cannot appear to be captured (cage, observation tank, etc.) to depictions of animal cruelty.

Skull size:

• Artists requested: 12in x 5in (LxW)

Movement:

• Eye moves up + down + left + right

• Eyelid moves up + down

• Jaw moves up + down

The end of the attraction must feature a dinosaur jump scare with different expressions based on win or loss.

Enclosure:

• Fits in a box size: 56cm x 100cm (LxW)

• Fits through a window sized: 6.5in (W)

• User Experience requested: Centered at the wall at 110cm high.

• Dinosaur cannot appear to be captured (cage, observation tank, etc.) to depictions of animal cruelty.

Skull size:

• Artists requested: 12in x 5in (LxW)

Movement:

• Eye moves up + down + left + right

• Eyelid moves up + down

• Jaw moves up + down

Idea 1: The head lies on the ground and is rotated  to an upright position. (Problem: lifting the whole body against gravity requires a very powerful motor with a lot of torque. Probably expensive.)

Idea 2: Head is held upright using a cable in tension. Head is reset by retracting the cable. (Problem: we are still lifting the whole head. It will be very heavy.)

Idea 3: Head is always held upright, head hides behind a wall and rotates into view. (Problem: might be unstable, need a counterweight. Need a lot of width for head to be completely out of view.)

We liked idea 3 the most because the motor would not be working against gravity. 

Given our room constraints and desired head size, are we able to fit the dinosaur head and hide it around the corner? CAD says yes!

A concern that was brought up was:

• Is the user able to punch the dinosaur?

Although this behavior is not encouraged, we understand that a frightened user might act without thinking and some users might act irresponsibly.

To prevent contact with the dinosaur, we thought about placing a desk in front of the enclosure, placing a plastic covid shield, adding a scrim, and having the dinosaur jump out of a window/wall like a jack-in-the-box.

Due to size limitations of our booth, we had trouble adding obstacles in our booth. Instead, when the dinosaur pops out, the user will be solving a puzzle on the other side of the room. The distance will give users more time to react and adjust to the dinosaur. We will also add an operator close outside of the room but still close to the dinosaur to control interactions with the dinosaur.

A big influence on many of our approaches was the project I had just worked on: Oscar the Grouch (Robotic Hand Puppet)

The influence was very apparent in the use of 4-bar linkages for eye and mouth movement.

Oscar's limbs couldn't move because the servos were too low powered. For the dinosaur, we consulted the artists about how much the skin and foam would weight and we ran a rough torque calculation based on measurements. We then bought motors that far exceeded our needs.

In Oscar, there was minimal support for the outside material, making it difficult to sculpt and attach material. This time, we added more plates to sculpt a more detailed head. The plates are made of wood to glue sculpting foam more easily.

A collection of our progress leading up to Spring Carnival.

When we started testing the rotating arm, we grew concerned with how much the stand was shaking.

We thought that the sandbags would reduce the shaking but we were wrong. With the added weight of the skull, the shaking became even more violent.

While reducing the rotation speed also reduced the shaking, our solution was to support the middle of the structure to the wall using leftover wood (not photographed).

IT WORKS!!!

https://youtube.com/shorts/uLk6XO6OhGQ?feature=share

During inspection, right before opening, our dinosaur was mishandled and could no longer rotate.

We decided to keep the dinosaur rotation static and only move the eyes and mouth.

We also realized that due to the angle of the enclosure, the eyes were not visible to the user.

We may have built the robot dinosaur, but Sophie gave life to the velociraptor.

Thank you Sophie!

From left to right:

• Sophie

  • Skinner.

  • Brought the robot to life.

  • Added skin and foam to the mouth, teeth, and skull.

• Jessica

  • Designed the outline of the skull.

• Namky (me!)

  • Designed the support for the head/body.

  • Consulted on movement and electronics/motor selections.

• Matthew

  • Team lead. Communicated with other teams.

  • Wired the electronics.

  • Programmed the motors and electronics.

• Audrey

  • Designed for eye and jaw movement.