Wireless Car

Breathalyzer

Ignition Lock System

Matt Lorch & Joshua Fajardo-Frink

At A

Gla

nce

Breathalyzer Unit Instructs

User to Blow

Breathalyzer Unit Takes Reading

Sends Data to Dash Unit

Dash Unit Displays BAC

If Sober, Dash Unit Allows

Ignition to Start for 5

Seconds

Two Device System

Bre

ath

aly

zer

Transm

itte

r

Rece

iver

& L

CD

Inte

rface

Major

Components

Alc

ohol G

as

Senso

r M

Q-3

Analog Biometric Sensor

* “Fast response” and High sensitivity

* Stable and long life* Simple drive circuit

FromHANWEI ELETRONICS CO.,LTD

ADC Initialization

void initADC(void) {

ADCSRA |= (1 << ADPS2) | (1

<< ADPS1) |(1 <<

ADPS0);

// Set ADC prescalar to 128 - 125KHz

// Set ADMUX Register

// Makes AVCC the ADC reference val.

ADMUX = 0b01000000;

//Use ADC0 (No MUX adjustment required)

ADCSRA |= (1 << ADATE); // S

et ADC to Free-Running

mode

ADCSRA |= (1 << ADEN); //

Enable ADC

ADCSRA |= (1 << ADSC); //

Begin A2D conversions

}

For grabbing all 10 bits:

Long bob = (ADCH << 8) | (ADCL); /

/ store all 10 bits from

ADC

Code S

nip

pets”

0 1000 2000 3000 40000

100

200

300

400

194

364

Data

Gra

phin

g

0.00 BAC

Impaired BAC

0 5000 10000 150000

200

400

600

800

1000

196

936A

DC

Valu

eA

DC

Valu

e

Sample

Sample

XB

ee®

Radio

An Elegant and Effective Wireless Solution

* UART for Easy Data Transfer (256kps

Transfer Rate)* Uses 2.4Ghz Frequency Band

*Range of 100 ft. in doors.

* Low Power Consumption* Runs on 2.4-3.4V

FromHANWEI ELETRONICS CO.,LTD

Receiving Data

Code S

nip

pets”

Dash Unit Continuously Listens for Characters in RX

Standard UART with 8 Bit Data, No Parity, & 1 Stop bit

Baud Rate Set to 9600

Characters Used as Commands:

‘ ; ’ – Clear LCD & Allows Characters to Write to LCD

‘ * ’ – Runs Ignition Unlocking for Short Time

‘ / ’ – Stops Displaying Characters on LCD

Time for a Demonstration!It’s just mouthwash.

Marketability

Rental Cars

Truck Drivers

Court Orders