Passenger/Item Detection System for VehiclesDec03-05 members

• Jason Adams• Ryan Anderson• Jason Bogh• Brett Sternberg

Acknowledgements• Clive Woods – Advisor

• Heart of Iowa Regional Transportation Agency (HIRTA) – Client

Presentation Outline• Introductory Materials

• Assumptions & Limitations

• Accomplishments

• Technical Approach

• System Design

• Implementation & Testing

• Resources & Schedules

• Closing

Problem Statement

• Need to prevent passengers from remaining on the bus after the driver leaves the bus.

• Need for automatic detection system- Rectifies problem of driver not checking the bus

General Solution-Approach Statement• Develop initial design

• Present design to client for approval

• Order parts

• Assemble prototype circuits

• Test prototype circuits

• Combine circuits into complete detection system

• Test detection system

Operating Environment• Transient bus

• Vibrations- Bus’s engine

- Roadways traveled• Environmental elements

- Dust

- Dirt

- Moisture

• Normal temperatures

• Withstand pressure given off by passengers

Intended Users/Uses

Users• male or female adult• commercial driver’s license• no discrimination on the basis of sex, ethnic background, physical

size, or disability• able to operate the commercial vehicle according to the laws of the

state.

Uses• automatically detect remaining passengers and possible items • alarm driver of the situation before he or she has fully exited the bus.

Assumptions• Will be used on a transient bus

• Occupancy ranges from ten to seventy-five passengers

• System off while bus is running

• System starts when bus shuts off

• Automatic

• Versatile

• Pressure sensors cover all seats

• LED’s attenuation is eight to ten feet

• Photodiode sensitive to LED only

Limitations• Cost not to exceed two hundred fifty dollars

• Power for the system comes from bus’s battery

• Structure of the bus

• Response time

• Self-operational

• Operating environment

• Spectrum of LED

End Product and Other Deliverables

• Passenger detection system

– Seat pressure system

– Floor optical system

• Technical specifications for parts

• Installation directions

• End product design report

– Cost analysis report

Present Accomplishments• Defined problem

• Determined possible technologies

• Researched possible technologies

• Eliminated non-feasible technologies

• Designed initial circuit designs

• Presented design to HIRTA

• Ordered Parts

• Produced prototype circuits

• Lab tested prototype circuits

Technical Approach

• Light sensitive resistors

• Pyrometers

• Ultra-sonic signature

• Pressure sensitive resistors

• Optical counters

• Photodiode (detector)

• Weight systems

• Piezoelectric sensors

• Magnetic counters

• Infrared LED (emitter)

• Analog alarm system

• Digital display system

Alarm System Approaches

Technical Approach Results

Hybrid system

• Seats - pressure sensitive resistors

• Floor - infrared emitters / photodiode detectors

Research Activities

• Phase detection

Remove overlapped signals of unwanted emitters

Synchronous detection methods allow detectors to accept only wanted signals

• Seat weight distribution

Distribute weight located anywhere on a seat to the force sensor

Design Constraints

Physical properties – System should not be restrictive, distracting, or discomforting to the driver and passengers.

Size – System should not interfere with normal bus operations. Fail-safe – System should never neglect to alert if a passenger is

present when the bus is shut off.

Power consumption – Power from the system must come from a 12-volt battery.

Response time – System will need to respond within 3-7 seconds of the bus being shut off.

Design Constraints (cont’d)

• Robust – System may be exposed to the elements and anything tracked on by passengers such as: rain, snow, mud, dust, and dirt.

• Flexible – Design implementation must be supported for several bus designs.

• Cost effective – If system cost is over $100, some type of funding must be provided.

System DesignPart I: Pressure Sensors

Purpose: – To detect a left behind passenger and/or item located on

the seats.

Basic Operation:– If pressure is detected on the sensor then an analog signal

is output triggering the alarm.

Pressure Sensors

Bus Schematic – Pressure Sensors

Force Sensitive Resistor Sensors

Wiring

Buzzer Alarm System

• Force-to-voltage circuit• Rf sets sensitivity of circuit• Signaling voltage pre-determined according to Rf• Output will signal parallelizing circuit to trigger alarm

Pressure Sensing Circuit

• Initial force-to-voltage circuit design

– Removed negative voltage from op-amp

– Altered input voltage to incorporate bus battery voltage

• Short range of linear output voltage– Set alarm trigger voltage within the linear range

• Size of sensing surface area small– Install a surface to distribute weight from anywhere on

the seat to the sensing area

Pressure Sensor Implementation

• Testing output voltage of force-to-voltage circuit (lab)

– Variable pressure sensor sensitivities (1 lb, 25 lb, 100 lb)

– Variable input voltages

– Variable Rf resistance

•

• Largest S occurred with 100 lb sensor and Rs = 100 kΩ– Voltage difference = 3 V

Pressure Sensor Testing

System DesignPart II: Optics

Optics

Purpose: •To detect a left behind passenger and/or item located on the floor.•To detect a left behind passengers in a wheelchair

Basic Operation:•Emitted light that is blocked will cause the alarm to be triggered

Optics

General Layout:

Seat WheelDriver

Seat

Seat

Seat

Seat

Seat

Seat

Seat

Seat

Seat

SeatChair

Seat

Ligh

t

Ligh

t

Ligh

t

Optics

General Layout:

Exhibit A Exhibit B

Exhibit A demonstrates a much more efficient configuration among the emitter and detectors!

Optics

Why Infrared light?• To prevent interference from ambient light• Optical receiver designed to only recognize infrared light

(tinted photodiode)• To maintain a failsafe detection system

Optics

Benefits: • Low Cost • Small (Will not alter the aesthetics of the bus)• Very low maintenance • System does not impose any health risk

Optics

Drawbacks:• Tampering with may cause issues

Solution: -Enclose in box-type structure-Sheet of plexy-glass over aperture

Emitter or Detector

Optics

Transmitter

INFRARED EMITTER

D-FLIP FLOPSWITCH

12 V

SQUARE WAVE

5VBATTERY

TRANSISTOR (BJT)

VOLTAGEREGULATOR

BUS

SINE WAVE 50-50 SPACEDOSCILLATOR30 KHz

INFAREDLIGHT

Optics

Receiver

TRANSISTOR(BJT)

DIODE TRANSISTOR(BJT)

AMPLIFIER AMPLIFIER PHASE DETECTIONCIRCUITTRANSISTOR

(BJT)ALARM

INFRARED DETECTOR AMPLIFIER

Optics

Phase Detection (in phase)

Optics

Phase Detection (90˚ out of phase)

Alarm

• Both the pressure sensors and optics will be able to trigger the alarm

• Alarm in consideration has the following features:-90 dB buzzer

• Some other sound levels -Conversation ---------------> 60 dB

-Rock Concert ---------------> 110 dB

Cost Analysis

Personnel Name Total HoursAdams, Jason 165Anderson, Ryan 140Bogh, Jason 140Sternberg, Brett 160

Personal Effort (Total of 605 Hours)

Brett Sternberg\160 Hours

26%

Jason Adams165 Hours

28%

Jason Bogh140 Hours

23%

Ryan Anderson140 Hours

23%

Adams, JasonAnderson, RyanBogh, JasonSternberg, Brett

Personal Effort

Item Cost1- 75dB Piezo Electric Buzzer $2.993- Infared LED pk/3 $3.007- 5 kohm resistor pk/5 $6.237- 0.1uF Capacitor pk/5 $6.937- LM339 Comparator $6.9314- LM741CN Operational Amplifier $12.4614- 1 kohm resistor pk/5 $12.467- Photodiodes $21.008- Circuit Chip & Wiring $40.0010- Flexiforce Pressure Sensor $100.00

Total $212.00

Other Resources' Cost

$2.99

$3.00

$6.23

$6.93

$6.93

$12.46

$12.46

$21.00

$40.00

$100.00

$0.00 $20.00 $40.00 $60.00 $80.00 $100.00 $120.00

1- 75dB Piezo Electric Buzzer

3- Infared LED pk/3

7- 5 kohm resistor pk/5

7- 0.1uF Capacitor pk/5

7- LM339 Comparator

14- LM741CN Operational Amplifier

14- 1 kohm resistor pk/5

7- Photodiodes

8- Circuit Chip & Wiring

10- Flexiforce Pressure Sensor

Other Resources’

Cost

Item W/O Labor With LaborParts and Materials 1- 75dB Piezo Electric Buzzer $2.99 $2.99 3- Infared LED pk/3 $3.00 $3.00 7- 5 kohm resistor pk/5 $6.23 $6.23 7- 0.1uF Capacitor pk/5 $6.93 $6.93 7- LM339 Comparator $6.93 $6.93 14- LM741CN Operational Amplifier $12.46 $12.46 14- 1 kohm resistor pk/5 $12.46 $12.46 7- Photodiodes $21.00 $21.00 8- Circuit Chip & Wiring $40.00 $40.00 10- Flexiforce Pressure Sensor $100.00 $100.00

Subtotal $212.00 $212.00Labor at $10.00 per hour:a. Adams, Jason $1,650.00b. Anderson, Ryan $1,400.00c. Bogh, Jason $1,400.00d. Sternberg, Brett $1,600.00

Subtotal $0.00 $6,050.00Total $212.00 $6,262.00

Final Project Cost ($6262.00)

$212.00

$6,262.00

$0.00

$1,000.00

$2,000.00

$3,000.00

$4,000.00

$5,000.00

$6,000.00

$7,000.00

Parts Labor

Item

Cost

Final Projected Costs

Project % Start FinishProject Definition 01-Feb-2003 08-Feb-2003Project Definition (Revised) 01-Feb-2003 08-Feb-2003 Project Definition Completion 01-Feb-2003 03-Feb-2003 Project Definition Completion (Revised) 01-Feb-2003 03-Feb-2003 End User(s) End use(s) 03-Feb-2003 04-Feb-2003 End User(s) End use(s) (Revised) 03-Feb-2003 04-Feb-2003 Constraint Identification 04-Feb-2003 08-Feb-2003 Constraint Identification (Revised) 04-Feb-2003 08-Feb-2003Technology Considerations 06-Feb-2003 08-Mar-2003Technology Considerations (Revised) 06-Feb-2003 08-Apr-2003 Identification of Technologies 06-Feb-2003 10-Feb-2003 Identification of Technologies (Revised) 06-Feb-2003 10-Feb-2003 Identification of Criteria 10-Feb-2003 12-Feb-2003 Identification of Criteria (Revised) 10-Feb-2003 12-Feb-2003 Technology Research 12-Feb-2003 06-Mar-2003 Technology Research (Revised) 12-Feb-2003 06-Apr-2003 Technology Selection 06-Mar-2003 08-Mar-2003 Technology Selection (Revised) 06-Apr-2003 08-Apr-2003End-Product Design 10-Mar-2003 20-Apr-2003End-Product Design (Revised) 10-Apr-2003 15-Apr-2003 Identification of Requirements 10-Mar-2003 15-Mar-2003 Identification of Requirements (Revised) 10-Apr-2003 11-Apr-2003 Design Process 20-Mar-2003 12-Apr-2003 Design Process (Revised) 11-Apr-2003 12-Apr-2003 Document Design 13-Apr-2003 20-Apr-2003 Document Design (Revised) 13-Apr-2003 15-Apr-2003Prototype Implementation 24-Aug-2003 18-Sep-2003Prototype Implementation (Revised) 24-Aug-2003 18-Sep-2003 Identification of Limitations 24-Aug-2003 28-Aug-2003 Identification of Limitations (Revised) 24-Aug-2003 28-Aug-2003 Implementation of Prototype 29-Aug-2003 18-Sep-2003 Implementation of Prototype (Revised) 29-Aug-2003 18-Sep-2003End-Product Testing 19-Sep-2003 20-Oct-2003End-Product Testing (Revised) 19-Sep-2003 20-Oct-2003 Test Planning 19-Sep-2003 01-Oct-2003 Test Planning (Revised) 19-Sep-2003 01-Oct-2003 Actual Testing 02-Oct-2003 15-Oct-2003 Actual Testing (Revised) 02-Oct-2003 15-Oct-2003 Results Evaluation 16-Oct-2003 20-Oct-2003 Results Evaluation (Revised) 16-Oct-2003 20-Oct-2003End-Product Documentation 21-Oct-2003 10-Nov-2003End-Product Documentation (Revised) 21-Oct-2003 10-Nov-2003 End-user Documentation 21-Oct-2003 30-Oct-2003 End-user Documentation (Revised) 21-Oct-2003 30-Oct-2003 Maintenance Documentation 31-Oct-2003 10-Nov-2003 Maintenance Documentation (Revised) 31-Oct-2003 10-Nov-2003End-Product Demonstration 11-Nov-2003 20-Dec-2003End-Product Demonstration (Revised) 11-Nov-2003 20-Dec-2003 Demonstration Planning 11-Nov-2003 12-Dec-2003 Demonstration Planning (Revised) 11-Nov-2003 12-Dec-2003 Faculty Advisor Demonstration 14-Dec-2003 15-Dec-2003 Faculty Advisor Demonstration (Revised) 14-Dec-2003 15-Dec-2003 Industrial Review Panel Demonstration 16-Dec-2003 17-Dec-2003 Industrial Review Panel Demonstration (Revised) 16-Dec-2003 17-Dec-2003Project Reporting 01-Feb-2003 20-Dec-2003Project Reporting (Revised) 01-Feb-2003 20-Dec-2003 Project Plan 01-Feb-2003 10-Feb-2003 Project Plan (Revised) 01-Feb-2003 10-Feb-2003 Project Poster 01-Mar-2003 14-Mar-2003 Project Poster (Revised) 01-Mar-2003 14-Mar-2003 Design Report 01-Apr-2003 06-May-2003 Design Report (Revised) 01-Apr-2003 15-Apr-2003 Final Report 11-Nov-2003 20-Dec-2003 Final Report (Revised) 11-Nov-2003 20-Dec-2003 Weekly Email Reporting 01-Feb-2003 20-Dec-2003

Oct Nov DecJul Aug SepApr May JunJan Feb Mar

Milestone Percent Completed

Project Definition 100

Technologies Considered 100

Ordering of Prototype Parts 100

Construction of Prototype 100

Testing of Prototype 75

Final System Construction 0

Final System Testing 0

Remove Bugs from Final System 0

Project Total 75

Project Evaluation

Commercialization

• The cost to produce the product is very difficult to determine- Each system depends on size of bus or vehicle- Each system must be installed during construction of the vehicle

• Potential market for this product is large- Every large capacity transportation company (bus, airline)

Recommendations for Additional Work

• Detect items in specific locations

• Timer/Delay

• Alarm fully on or off

• Reset/override

• Digital display

Lessons Learned

• Practical and applicable solution

• Time constraints and inability to catch up

• Circuit design

• Research techniques

• Application of engineering skills to real world problems

• Set more strict deadlines

• Documentation

Risk and Risk Management• Time consumption of learning the technologies used

– Consulting advisor more often than not• Complete redesign of optoelectronics

– Learn the technology• Delay in ordering parts

– Ordered parts as soon as possible• Unavailability of times for the team to meet

– Two smaller teams• Reliability of the breadboards used in circuitry

– Troubleshoot, troubleshoot• Receiving wrong parts

– Use replacement parts– Redesign circuitry

•Small size of the pressure sensing area– Find a surface to distribute weight to the sensor

Closing Summary

• Passenger detection system

• Hybrid design using two technologies

– Floor space : Optoelectronics

– Seats : Pressure sensors

• Automated

• Eliminates the factors of human error

Questions?