SMOKE SENTRY 2Preliminary Design Review

Senior Design Clinic

Team 10

Team Members and Roles Core Team:

Jeff Frank (EE) – Team LeadKelvin Kosbab (EE)Tim Nguyen (EE)Mike Masek (ME)

Advisor: Ramesh Rajagopalan Observers:

Chris Engelmann (Sponsor)Kevin Nicholson (Engineering Coordinator)

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Background

Smoke from fires and cigarettes differs greatlyCigarette smoke particles:

○ Considerably smaller○ Reduced particle concentration

Commercial smoke detectors are designed for fires○ Insensitive to cigarette smoke

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Problem Statement

Very challenging for hotels to enforce no smoking policies Some guests are sensitive to smoke residue

○ Discomfort○ Health issues○ Unpleasant odors

Smoke damage can result in thousands of dollars in repair costs

Customer needs system capable of notifying hotel staff of smoking violations

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Statement of Work

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Statement of Work

Deliverables:Research documentationDesign documentationPrototype of a cigarette smoke monitoring

systemTest specificationsData supporting a prototype functioning

within specifications

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Customer Requirements

Cost target: Detection Unit: < $50Monitoring Station: < $1,500

Size target: < twice fire smoke detectorssmaller than 8.5” x 8.5” x 3”

Improved sensitivity over existing detectors

Network capable of 100 room hotel Functional under US regulations

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Requirements Validation

Functional Requirement Validation

Capable of detecting cigarette smoke

Minimize false positives < 2 per hotel

Latency Network: < 20 seconds Detection: < 5 minutes

Establish controlled tests Record conditions

Run in controlled setting Count total false positives

Measure using timestamp

Testing in similar room

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What is Smoke? Gases

Carbon monoxide, nitrogen oxide

ChemicalsFormeldehyde, acrolene, benzene

ParticulatesNicotene, phenol, polyaromatic hydrocarbonsSize: 100 – 4,000 nm

http://www.engineeringtoolbox.com/particle-sizes-d_934.html

http://cancercontrol.cancer.gov/tcrb/monographs/7/m7_5.pdf 9

Work Breakdown Structure

Design choices have little effect on each other

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Smoke Detection

Cigarette smoke (average):

100 nm – 300 nm

Goal: optimize laser technique Increase sensitivity

○ Obscuration○ Particle size

Minimize false positives

Type of Detector

Obscuration Level(% obs/m)

Particle Sensitivity Range(nm)

Ionization 2.6 – 5.0 10 - 300

Photoelectric 6.5 – 13.0 300 – 10,000

Laser 0.06 – 6.41 N/A

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Ionization Method

Smoke Absent Smoke Present

http://www.epa.gov/radiation/sources/smoke_ion.html 15

Ionization Design Tweaks

Dual chamber sensorRejects fluctuations in humidity and

atmospheric pressure Increase current between plates

Larger voltageMinimize distance

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Implementation Difficulties

Measuring pico-Amps Design and construction of ionization

chamber Radioactive material

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Photoelectric Method

Smoke Absent Smoke Present18

Optimization Design Tweaks Laser Diode

Much brighter than LED

635 nm Photo-sensor array

Minimize ambient light

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Optimization Design Tweaks

Optical techniquesMirrorsLensFilters

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Optimization Design Tweaks Lock-in Amplifier

Laser sine wavePhotosensor sine wave

Noise rejectionAll frequencies components not equal to

sine wave attenuated○ Ambient light○ High frequency transients

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General Techniques

Optimize airflow into smoke chamber Concentrate airflow to one area

Laser beam path Algorithm rejects dust detection

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Flame Detection

UV and IR detection in combination

Used as a secondary sensorApplied as an aid for primary sensorIncrease sampling rate of Photoelectric

sensorSend notification to front desk

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Sensor Nodes: Microprocessor Requirements on microprocessor not

demandingChoose a PIC from Microchip

○ Many microprocessors availableChoose the smallest, cheapest one with

enough I/O and peripherals

Requires SPI, timer, sufficient I/O pins

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Wireless Network

Transmitted DataSmoke statusFlame statusRoom #Time Stamp

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Wireless Network Protocol IEEE 802.15.4

Low data rate, Personal Area Networks○ Zigbee○ MiWi

2.4 GHz – International○ 250 Kbit/s○ Shorter range

915 MHz – North America○ 40 Kbit/s○ Longer range

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MiWi Less complex implementation of ZigBee

Shorter development time○ MiWi Development Studio○ ZENA

MiWi standardizes…Network protocol

○ Software package

Transceivers

Hotel room capability: 8,128Mesh routing 28

Monitoring Station Application run on Windows 7 laptop

USB connected MiWi transceiver (ZENA)

Option 1: LabVIEWPros: Easiest to implement, most of the

programming already doneCons: License fee, not as flexible, limited

hardware options (NI hardware only)

http://labviewwiki.org/images/thumb/3/32/LabVIEW_Logo_Vertical_4c.jpg/200px-LabVIEW_Logo_Vertical_4c.jpg

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Monitoring Station Option 2: Java application

Communication with ZENA via C commands and system commands

Pros: Free, flexible, easy to implement, more control, experience in Java programming

Cons: more coding, more testing

http://www.digitaltrends.com/computing/most-vulnerable-browser-plugin-think-java-not-flash/

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Design Summary

Cigarette DetectionSmoke detection – Laser (Photoelectric)Flame detection – UV & IR

Wireless NetworkMiWi

Monitoring StationJavaZENA

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Project Schedule

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Budget

Total Allocated Budget = $2,500○ Cigarette Detection

$200

○ Wireless Network$500

○ PCB & Housing$400

○ Miscellaneous Prototyping$300

Estimated Cost: $1,400

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QUESTIONS?

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