Mechanical

First prototype

Before starting the mechanical part of the project, we prototyped our design. We took a cardboard box and covered with inside with black paper to avoid light reflection. We cut a window for observing the pet and another one for manually controlling the screen with a picture of eyes.

The prototype confirmed our vision, and we continued working on the project.

Prototype 1.mp4

Eye Kinematics

One of the most time-consuming parts of our project was the mechanical design of the eye-motion system.

Sketches of Kinematics: Early stage sketches of possible methods

Choosing Kinematics:Virtual experiments in SolidWorks

Prototype Kinematics.mp4

Prototype of Kinematics: Physical prototyping with DC motors

After several prototypes of more complex mechanisms, we simplified our approach to a single degree of freedom mechanism due to time constraints and the number of available pins on the microcontroller. The vertical movement of the eyes would be controlled by a servo motor, while the horizontal movement of eyes would be animated on the LED display. Servo rotations would be transmitted to vertical, linear motion through a wheel and pulley system.

Mechanism_Video.MOV

IMG_3745.mov

For the primary eye mechanism, we built several prototypes and failed. Learning from them, we built one final design that met our expectations.

To economize pin usage on the microcontroller, we reduced our scope to use only one motor to manipulate the eyes. To reduce pins further (no H-bridge) and for easier position control, we chose to use a servo motor. This allowed us to control the speed and direction of eyes with only one pin.

Through iteration, we reduced the mechanical complexity of the system to improve robustness, friction, cost, and ease of construction.

We designed a slot in a wall to use as a rail for a carriage. The frame for the display is mounted on the carriage. The carriage and wheel are 3D printed and linked with rope.

Housing

We designed a case for our device in a CAD and cut parts from Duron sheets on a laser cutter. To make the design flush with the external box, we designed corner joints to hold the plates together. Most of the dimensions of the device were chosen during early tests and prototyping.

CAD

Laser Cutter File

3D Printed Plastic Corner Joints

Aesthetics

The cherry on top is the cute, informational stickers we designed for our device. They also explain how to interact with The Void.

Page updated

Report abuse