Design Project: Bop-It!

University of Pittsburgh; Department of Electrical and Computer Engineering
ECE 1895: Junior Design Fundamentals
Team: Thomas Driscoll, Meara Murphy, Elizabeth Steward

Design Overview

Our design is a variation of the popular game “Bop It”. Our three distinctly different tactile commands are Squeeze It, Shake It, and Flick It.

·       Squeeze It: A stress ball with a conductive pressure sensitive sheet glued inside
·       Shake It: Utilizing a tilt sensor
·       Flick It:  A joystick that accepts movement in any direction

Although our group tested out many different types of audio outputs to indicate which input the game expects the user to enter, we settled on using a buzzer to emit a sequence of notes unique to each input. Our visual cues for the player utilized a RGB LED: red for an incorrect move resulting in a lost game; green for correct inputs; blue for the start and completion of each game played.

Tom was responsible for writing the pseudocode, designing the Upverter schematic and PCB with Lizzie, testing and soldering the PCB board with Meara, and creating the enclosure for our design. This involved taking precise measurements of our final PCB board, designing the enclosure on Fusion 360, 3D printing the design, and fitting the PCB board inside it.

PCB Schematic & Layout

To start, we centered the ATMega328 chip, as this is the focal point of our design. Then, we created all our components and their necessary auxiliary components, such as capacitors, resistors, and ground nets. The schematic was connected using busses. As this was the easiest way to keep track of individual inputs and outputs on the board.

There are a few male header pins in place of components on the board. These were specifically chosen so we could use female-to-female wires to get secure components further away from the PCB, outside of the enclosure, for user interaction. This was especially true for our Squeeze input, as the user is required to squeeze a stress ball with a Velostat pressure-conductive sheet inside.

Enclosure Design

The enclosure was the last to be designed after the PCB and parts were chosen. We could have used the PCB layout to determine part spacing and datasheets for other dimensions, but with the slow rolling shipment of parts and the changes we had made, it was better to measure the parts and dimensions after our design was assembled in its entirety.

Measurements were made of each of the components protruding significantly from the PCB board that needed clearance,  such as the headers and tilt switch, as well as the parts we wanted to expose, like the hex displays and start button. More measurements were taken of the joystick breakout, MP3 trigger board, speaker, and battery. These were all modeled in Fusion 360, which allowed us to rearrange and reconfigure the parts. The most compact arrangement to fit the design placed the joystick on the left, ball on the right, main PCB on the top with the hex displays, button, and toggle switch, and the remaining parts arranged underneath to make one package. The enclosure designed around this arrangement consists of: Top and bottom lid, body, joystick cap, claw, and a center brace.

The enclosure design was manufactured in individual parts on a 3D printer over the course of two days. The various parts were screwed, glued, and fitted in as intended, with the only modification being the removal of one arm of the claw. The components and PCBs were then assembled and installed, completing the design.