The Smart Bridge:
Individual Project Concept Study

Cristiane J. Likely
David Greene and Pat Sullivan
Group #7, Dr. P. Kogge
EG498a: Multidisciplinary Engineering Design Lab
College of Engineering
University of Notre Dame
8 September 95

Introduction

In keeping with the ultimate objective of introducing the engineering method to freshmen engineering students in laboratory using the LEGO control kit and the LOGO programming language, I present the lab to be given a finite set of resources, design and implement a drawbridge that meets a set of given criteria in a finite time frame.

The "smart bridge" project is a project where a team of students utilizes the engineering method and each others experiences and knowledge of basic math and physics to build a better, smarter structure of the drawbridge design. The notion of competition can also be introduced where the winning group is the one that's bridge is the most engineering conscious, functional, and practical.

Objective And Goals

The goal of the project is to introduce freshmen engineers to the different fields of study in the College of Engineering being Civil, Mechanical, Computer Science, Electrical, and Chemical by integrating all these in a comprehensive object. Keeping in the spirit of practical engineering this lab allows the students to relate their designs to real life-sized bridges. It opens up to them the ability to research bridge design and apply that to their own project design. It gives them the sense that they are not merely playing with childhood toys, but are doing what professional engineers do in society. The project design involves civil and mechanical engineering in planning and developing strong structures and joints. Electrical and chemical engineering to wire the devices effectively and efficiently. Computer science and computer engineering to program the project to perform certain functions and routines.

This project keeps in mind several important criteria. First being it's relative simplicity in conjunction with it's vast range of possibilities. There is always more than one way to design a bridge, therefore the students are able to be as creative as possible but still be in the realm of functionality. The bridge must be able to meet several criteria: (1) have a solid structural integrity (2) it meets certain criteria as far as weight, length and height, (3) perform certain basic functions such as several ways to detect under bridge traffic, when to lift the drawbridge, how fast the bridge is to be drawn up, and various other safety features.

Criteria

The following are the criteria that must be met for the implementation of the bridge:

(1) The full length of the bridge cannot be shorter than 2 feet nor longer than 2 and one quarter feet long.
(2) The full width of the bridge cannot be wider than 8 inches nor narrower than 4 inches.
(3) The under bridge clearance has to be 4 inches ± 1 inch.
(4) The bridge must have several safety features:
a. There must be two gates that lower 5 seconds before the bridge starts to draw.
b. There must be a siren that sounds when the gates are coming down and a different siren sound when the drawbridge rises and descends. The siren should stop when the motion of the gate or drawbridge has ceased.
c. There must be a manual emergency button that can either stop or start the bridge to rise or fall.

(5) The bridge should not rise more than 75 degrees.
(6) The bridge should be able to withstand XX amount of force upon it.
(7) Besides being limited to the assigned number or LEGO pieces, the bridge has the following material constraints:
- 1 light sensor
- 1 angle sensor
- 3 motors
- 1 sound piece
- 1 touch sensor
- 4 feet of string
(8) The final design must be finished in the time allowed.

The design of the bridge does not require any special equipment outside the basic kits. It does require extra basic parts such as the black connectors (which serve as bolts) and the long one row, multi-prong piece (which act as beams), and string. These pieces are very cost effective and cheap.

Method

The design and implementation of the bridge allows for engineering disciplines to contribute to the best possible design. There are essentially 5 parts to successfully implement any project. Brainstorming, narrowing, designing, building, evaluating, testing, and re-evaluating. Brainstorming involves the process of getting ideas and suggestions from all the group members. In this stage, no idea is a bad idea. The students should talk about how they want their bridge to look, what things might they need, what other aspects do they need to consider.

Narrowing and designing are the next steps where given all the possibilities and ideas from brainstorming, now it is time to narrow down to get some basic idea of the bridge and start building. The student throws out what they donŐt need and the ideas that arenŐt feasible. Designing involves, just that, designing the bridge while also keeping in mind all the previous planning. In this stage, the students will inevitably come across a design errors and unforeseen problems and they are faced with the situation where they will need to make design changes. They will also need to consistently check and evaluate their design as the they continue to build. They have to program different aspects of the bridge and incorporate the procedures into the larger code.

When the group feels that their design is complete, they need to test it given the criteria. If any component of the bridge is nonfunctional or does something outside of itŐs proper service, then changes will have to be made.

Conclusion

This purpose of the project was to introduce engineering freshmen to the fundamentals of engineering group design and the Ňengineering methodÓ. The project also gives the students Ňhands onÓ experience in several different engineering fields of study giving them a general view of what each field has to offer. The design of the bridge gives the students the opportunity to do so while keeping the costs to a minimum, offering creative input, giving satisfaction when their project is functional and working well, and the insight to the vast possibilities in the Department of Engineering.