Brake Intensity Advisory System Final Design Assessment Jace Hall Michael Purvis Caleb Trotter Edward Yri ECE 4007-L01 12/05/2011

2 Project Details What -BIAS (Brake Intensity Advisory System) operates by illuminating an auxiliary set of LEDS located around the perimeter of the standard brake lights when “hard braking” occurs Cost -The cost associated with mass production of the BIAS is projected to be $66.83

3 Project Motivation Why -The percentage of rear-end collisions (17% of all claims) ranks second among all automobile accidents Who -BIAS is intended for drivers and car manufacturers who are concerned with operating and manufacturing safer vehicles

4 Proposed vs. Actual Design Goals Proposed Design Goal Actual Design Feature Simple integration with current braking systems Design Goal Achieved Non-intrusive design Design Goal Achieved Real-time response Design Goal Achieved Software definability based on vehicle brake force parameters Design Goal Achieved

5 Proposed vs. Actual Technical Objectives Proposed Technical Objectives Actual Technical Performance Receive a voltage sensor output between V corresponding to a defined force. Tech. Objective Achieved Categorize the inputs into three defined states using the Mbed microcontroller. Tech. Objective Achieved Illuminate the auxiliary LEDs when a voltage of 1.9V or higher is received by the microcontroller. Tech. Objective Achieved Achieve a visual indication of braking force in real time. Tech. Objective Achieved

6 High Level BIAS Schematic

7 Implemented BIAS Design

8 BIAS Operation

9 Testing the Force Sensing Resistor Circuitry Output Specification 0 – 3.3 V output from the force sensing resistor circuit Testing Method The FSR was attached to the vehicle brake pedal, and the divider circuit resistor was sized to produce the appropriate output

10 Confirming Transition at the Hard Breaking Voltage Threshold Specification Real time response to the determined voltage threshold value Testing Method A volt meter measured the FSR voltage when the second LED array zone was initially illuminated. The value was 1.9 volts

11 Software Tests Specifications Three defined controller states corresponding to illumination parameters Software definability Testing Method LED output confirmed the controller states operated properly Sensitivity was altered to ensure software definability

12 Design Modifications 12 V voltage regulator added to reduce 13.8 V car outlet voltage 1.5 MΩ grounding resistor added to LED driver circuit Common grounding network established

13 Supporting Design Modification Figure

14 Problems Encountered and Solutions Problem: The LED driver circuit current limiting resistors were overloaded Solution: New resistors were added with higher power ratings Problem: LED brightness was not consistent Solution: Shorted soldering points were located, and fixed

15 Prototype Cost Analysis Prototype Expenditures -Of the requested $405, $ was spent - Many of the required parts were donated Mass Production Cost -Reduced hardware cost based on quantities purchased -Lower microcontroller cost based on reduction of features

16 Production Cost Break Down PartsMass Production CostPrototype Cost FSR$16.00$7.95 Wire/Connectors$5.50Donated Resistors/Voltage Regulator/Capacitors $4.95Donated Perforated Boards$5.75Donated Microcontroller$2.16Donated ($60) LEDs$19.25 LED Drivers$4.50 Parts Total$58.11$31.70 ($91.70) Contingency (15%)$8.72$4.76 ($13.76) TOTAL$66.83$36.46 ($105.46)

17 Marketability and Projected Profits –No automobile manufactures currently use a FSR to process braking force and illuminate brake lights accordingly –Profits from the system would come from royalty payments allotted to the patent holders Projected BIAS Royalty Profits Payment per Unit Installed $2.00 Projected Installations500,000 Total Profits$1,000,000 * Projected installations based on ~25% of the vehicles produced by Ford Motor Company annually

18 Improvements and Future Work Create a printed circuit board for control and FSR circuitry Integrate and program a lower cost microcontroller Fabricate lenses to cover LED arrays Test BIAS system on alternative vehicles