Specifications

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TABLE OF CONTENTS
1. INTRODUCTION ................................................................................................................................. 1
1.1 EXECUTIVE SUMMARY...................................................................................................................... 1
1.2 MOTIVATION ..................................................................................................................................... 2
1.3 GOALS AND OBJECTIVES ................................................................................................................. 3
1.4 COMPARISON OF EXISTING PRODUCTS ........................................................................................... 4
1.5 SYSTEM OVERVIEW ......................................................................................................................... 9
2. RESEARCH AND REQUIREMENTS .............................................................................................. 10
2.1 PLATFORM ..................................................................................................................................... 10
2.2 SYSTEM LOGIC............................................................................................................................... 12
2.3 VOLTAGE REGULATOR ................................................................................................................... 20
2.4 POWER & I/O INTERFACE............................................................................................................... 28
2.5 LEDS ............................................................................................................................................. 34
2.6 SOFTWARE ..................................................................................................................................... 37
2.7 INTERLOCK DEVICE ........................................................................................................................ 41
2.8 ENCLOSURE ................................................................................................................................... 42
2.10 ALCOHOL SENSOR ....................................................................................................................... 51
2.11 BATTERY ...................................................................................................................................... 56
2.12 CHARGING CIRCUIT ..................................................................................................................... 64
2.13 AIRFLOW MEASUREMENT ............................................................................................................ 71
3. HARDWARE DESIGN ...................................................................................................................... 74
3.1 SYSTEM DESIGN SUMMARY ........................................................................................................... 74
3.2 MICROCONTROLLER INTERFACE .................................................................................................... 76
3.3 POWER SUPPLY ............................................................................................................................. 83
3.4 DISPLAY ......................................................................................................................................... 88
3.5 PORTABLE UNIT CIRCUIT BOARD ................................................................................................... 90
3.7 CONTROL/BASE UNIT CIRCUIT BOARD .......................................................................................... 93
4. SOFTWARE DESIGN ..................................................................................................................... 100
4.1 SOFTWARE DESIGN SUMMARY .................................................................................................... 100
4.2 COMMUNICATIONS ....................................................................................................................... 103
4.2.1 WIRELESS COMMUNICATIONS FUNCTIONS ............................................................................................ 105
4.3 PORTABLE UNIT SOFTWARE ........................................................................................................ 106
4.3.1 DISPLAY FUNCTIONS................................................................................................................. 107
4.3.2 SAMPLING FUNCTIONS .............................................................................................................. 108
4.4 CONTROL UNIT SOFTWARE.......................................................................................................... 108
5. TESTING AND VALIDATION ........................................................................................................ 111
5.1 HARDWARE VERIFICATION REQUIREMENTS ................................................................................. 111
5.2 HARDWARE TEST PROCEDURE .................................................................................................... 113
5.3 SOFTWARE VERIFICATION REQUIREMENTS.................................................................................. 118