P13675: Bike Helmet Mirror System


Project Summary Project Information

One major cause of bicycling accidents is a vehicle overtaking the cyclist from the rear. Currently, riders have the option to use a side mounted mirror system to aid in their vision to the rear. However, this mirror arrangement has several drawbacks: distorted vision, difficult adjustment, and view obstruction. A multiple mirror system has been proposed by industrial design student Rob Fish, as seen in the following presentation. This system is mounted over the top of the helmet to provide a wide angle field of view behind the rider while being above the forward line of sight.

There were multiple issues with the prototype developed by Rob Fish. This senior design project will develop a helmet mounted mirror system that corrects for the issues seen in the prototype. Safety will be the biggest concern in designing and developing this system. Other considerations to be accounted for are minimizing the forward vision obstruction, maximizing the rear vision angle and image quality, and maintaining the proper image orientation. The ultimate goal will be a final product that is marketable in the cycling community that can be adaptable to multiple helmet styles currently on the market. However, the success of this senior design project will not be contingent on this ultimate goal being reached. This project will be deemed successful if it shows an improvement over the prototype in the areas detailed above. This project has the potential to be continued on in future MSD projects to perfect the design. The Project Readiness Package gives additional details about the senior design project overview.

This project is a student initiated project and was developed by Stephen Wess through the Design Project Management course. Due to this, there is no direct customer for the project. The acting customer for this project is Dr. Bernard Brooks, a professor in the School of Mathematical Sciences at RIT. Dr. Brooks is an avid cyclist and is familiar with the needs of the cycling community in developing an improved rear vision system.

Updated Description

Detailed Design & Preliminary Testing

Mirror Surface: Options for mirror surface were reflective Mylar, chrome window tint, spray on mirror, and acrylic. Each material was obtained and tested by the team for reflective image quality. Acrylic was determined to be optimal solution

Geometric Optics Analysis: Two and three mirror systems were analyzed for this design. A 50th percentile male head was used to determine the positions, curvature, and dimensions of the mirrors. Sensitivity analysis showed that the dual mirror system performed better.

Drop Test Analysis: To simulate the impact stress of dropping the designed system, a drop test analysis was performed using SolidWorks Simulation package. From this, adjustments were made to the design to strengthen and optimize the system

Finalized Concept & Rapid Prototyping

Dual Mirror System: Front mirror is in the user’s peripherals while the top concave mirror reflects the image behind the cyclist in the proper orientation.

Gooseneck: Gooseneck tubing is flexible enough to allow the system to attach to multiple helmet styles yet rigid enough to support the top mirror. Snap-fit Attachment: Snap-fits were utilized to increase the ease of assembling the system.

Dual-lock: Dual Lock allows users to easily attach and detach the bike helmet mirror system to helmets. ABS: ABS plastic was chosen for material properties including resistance to water, heat, and UV, and for its ability to be both 3D printed and injection molded.

Rapid Prototyped: The finalized concept was prototyped on the Fused Deposition Modeling (FDM) machine in RIT’s Brinkman lab. Acrylic: Heat was applied to the acrylic until it was pliable. Mirror was then molded to the proper curvature and attached using an adhesive.

Testing & Results

Rear Viewing Angle: The rear viewing angle specification calls for a minimum angle of 10 degrees (marginal) and 25 degrees (ideal). The system displayed a viewing angle of 40 degrees.

Rear Viewing Distance: The specifications require a distance of 130 feet (marginal) and 200 feet (ideal). The system was able to identify a vehicle at over 270 ft.

Wind Speed Resistance: The wind speed requirement was 45 mph (marginal) and 65 mph (ideal). RIT’s wind tunnel was utilized for testing. The system stayed attached to the helmet at the wind tunnel’s maximum speed of 130 mph. System Weight: The marginal value of the weight specification was 0.775 lbs., the total component weight was measured to be 0.403 lbs


The team successfully carried a concept proposed by an industrial design student into a working prototype that performs well with respect to the predefined engineering specifications.

Lessons Learned

Documentation Throughout Design Process: It is important to document the decision making progress through the design phase so people outside the group can follow the design’s progression.

Communication: Staying on the same page was key for the group in order to move forward with the project as one.

Back-up Plans: Keeping an updated Risk Assessment log was critical to project success. When we ran into issues regarding the reflective surface, we knew which materials to test next.

Future Work

Complete Testing: Finish testing specifications for (1) System Break Away Force and (2) Drop from Height.

Improved Stability: Design additional support for the front mirror in order to reduce vibrations.

Weight Reduction: Asses which components of the assembly weigh the most and redesign for lighter weight.

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Project Name
Bike Helmet Mirror System
Project Number
Project Family
Start Term
2012-2013 Winter Quarter
End Term
2012-2013 Spring Quarter
Faculty Guide
Rick Lux, 585-303-5995, ralddm@rit.edu
Primary Customer
Dr. Bernard Brooks, bpbsma@rit.edu
Sponsor (financial support)
MSD Project Office, mwspd21@rit.edu

Team Members

Member Role Contact
Zachary Kirsch Mechanical Engineer, PM zlk7086@rit.edu
Martin Savage Mechanical Engineer mhs4650@rit.edu
Olivia Scheibel Mechanical Engineer ovs8379@rit.edu
Henry Woltag Industrial and Systems Engineer hsw7863@rit.edu

Table of Contents - MSD I

Planning & Execution Systems Design Detailed Design Project Review

Customer Needs

Engineering Specifications

Project Schedule

Meeting Minutes

Team Code of Ethics


Concept Development

Functional Decomposition

SDR Risk Assessment

SDR Review Agenda

SDR Presentation File

SDR Meeting Notes

Feasibility Analysis

Technical Drawings

Comparing Design to Customer Needs & Specs.

DDR Risk Assessment

DDR Pre-Read

DDR Presentation

DDR Meeting Notes & Moving Forward

Table of Contents - MSD II

Planning & Execution Build, Test, Document Final Project

Meeting Agendas

MSDII Project Schedule

Current Week's Risk Assessment

Testing Plan

Updated Project Budget

Preliminary Drop Test Results

System Design Specs / Engineering Drawing Packet

Specification Testing Results

Final Presentation

Technical Paper


Current Design CAD Models