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PACE LITES PRESENTATION

Advisor: Professor SahakianAndrew DaiLenore KaplanBenjamin MattsonNikhil Sethi

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PACE global vehicle

PACE is a global collaborative project aimed at designing a new vehicle for the emerging market

Universities across the world are assigned different sub-systems

Northwestern is designing the electrical sub-system

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Goals Safety Minimize

weight Efficiency

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Sonar design utilizes transducers located inside the bumpers Powerful range finder Drivers receive alerts of

objects quickly approaching Onboard processing

An overhead view of the wave propagations from the front and rear of the vehicle.

Each transducer will be housed within the bumper, keeping a smooth surface across bumper face.

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Design detects objects at short and long ranges

Specs: 3 Ultrasonic transducers Center transducer short, wide

range Outside transducers long,

narrow range Senscomp 6500 ranging

module board Basic stamp microcontroller

An overhead view of the range covered by each transducer. Short range is emphasized with parking, long range is focused on collision avoidance.

The sonar works in tandem with the microcontroller in a multi-step process

The sonar system is controlled by the microcontroller, which is integrated into the vehicle’s engine control unit (shown in yellow).

The microcontroller runs the ranging module, which supplies source voltage to the transducers.

Step 1: Begin the sequence

- Microcontroller (MC) tells sonar receiver board to send 400 volt pulse to relay circuits

- MC connects first relay circuit

-MC starts timer

The microcontroller readout (highlighted in yellow) allows the driver to monitor the sequence from beginning to end.

Step 2: Transducer emits wave pulses

- 400v arrives at transducer

- Creates current in metal casing

- Causes diaphragm to flex

- Flex creates ultrasonic wave

Step 3: Reflected waves indicate object is present

-Wave encounters object

-Small portion reflects

-Reflection returns to transducer, causes slight flex

-Flex induces voltage

Step 4: The microcontroller receives detection signal and ends sequence

-Return pulse travels down original line to RB

-RB tells MC an object has reflected wave

-MC stops timer, records time

Step 5: The microcontroller runs code to decipher time to collision

The prototype functions both attached and independent of the vehicle

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Intervehicle communication allows increased awareness between vehicles Zigbee wireless system allows

inter-car communication System can warn others of

weather, incoming traffic, construction

Car Computer

XBee Module

Car Computer

XBee Module

LCD DisplayLCD Display

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The Zigbee standard offers benefits in range, and power Alternate technologies

Wifi – 300ft range Bluetooth – 3ft range

Specs Digi Xbee PRO modules <$25 <1W 5000ft range

Wireless prototype works on a modular basis Components

XBee modules ARM processor Blackbox input Host machine

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Communicating between Xbees and providing readable output

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Zone Number

Encoded Output

Range (in)

1 1000 0”-12”

2 1100 12”-20”

3 1110 36”-120”

4 1111 120”+

Converting output from sonar for transmission

Describing Zones to user

Testing the range and efficiency of the wireless system Tested RSSI (dBm) Transmitted 64bits Was able to operate at a range

of 1 foot to 120 feet.

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-52 -50-56

-68-62

-68-73 -75

-79-75 -74

-79-84

-80-85 -85 -87 -88

-84-90 -88

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

1 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 90 105 110 115 120

RSSI vs Distance

Prototyping enabled us to test for feasibility, range, robustness

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Goals Feasibility Testing

• Cost• Range• Power• Interference

Our prototype showcases a combined sonar and wireless system

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BASIC stamp microcontroller

12V Battery

5V Regulator

SensComp 6500 Ranging Module

Digi Xbee Module

BJT Switches

400V SS

Relays

Environmental Grade Sonar Transducers

Coaxial Cables

Digi Xbee Module Gateway Board

Laptop

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The prototype proves feasibility

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Multiplexing Overview

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Microcontroller (input)

Microcontroller (output)

Input controlsLEDs

LEDs

Sensor

Locks

Front of car Back of car

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Multiplexing allows large minimization of vehicle’s wires MOSFETs

Handles lots of current (60 A) No moving parts

Wire Gauge Less power loss for 8 gauge Easier assembly

PIC microcontroller Programmable communication 40 I/O

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Multiplexing connects all components in a modular fashion Multiplexing will:

Lower wire cost power loss

Connect all electrical components in PACE car

Multiplexing Reduces Installation Time and Cost Less wires mean less

assembly time Boothroyd Dewhurst

DFMA provides methods of predicting assembly time

Example Assembling Wires in wire

loom

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t n = 6.4 + 3.8Nw + (.5 + .4Nw )Lw

Parts for the virtual build

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Next Steps

Design sonar and wireless circuit boards specifically for PACE design

Create user interface Multiplexing

Program so that components are plug and play Universal connections

Testing Sonar Arrays

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Questions and Comments