The Design and Fabrication

The Design and Fabrication

of an Optical Sensor for Monitoring

of an Optical Sensor for Monitoring

the Growth of Mould in Buildings

the Growth of Mould in Buildings

Presented By: Anna Sauer

MEScCandidate in Electrical Engineering

Supervisors: Drs. Sabarinathan, Savory, & Scott

OUTLIN

EOUTLIN

E

•Project Background and Facility

•What is m

ould?

•Existing Technology for use in the

detection of mould

•Design Requirements

•The Full Sensor

•Components of the sensor

•Results

•Im

plementation

THE INSURANCE RESEARCH LAB

THE INSURANCE RESEARCH LAB

FOR BETTER HOMES

FOR BETTER HOMES

THE INSURANCE RESEARCH LAB

THE INSURANCE RESEARCH LAB

FOR BETTER HOMES

FOR BETTER HOMES

Interchangeable

panels to allow

for the testing

of different

finishes, such as

Aluminum

Siding, Brick,

etc.

WHAT IS MOULD?

WHAT IS MOULD?

•Microscopic organisms known as

fungi, includes: m

ushrooms,

yeast, and m

ould

•They play an important role in

nature –

degrading pant and

animal debris

•Reproduce through spores

•Spores can be tracked or blown

indoors on soil particles in the

air

MOTIVATIO

NMOTIVATIO

N

•Mould in buildings is a

major problem for

homeowners and insurance

companies, as it causes

costly property damage and

can pose serious health

risks.

•About 10% of children are

asthmatic and it has been

shown that this is strongly

correlated with indoor

mould growth.

CURRENT W

AYS OF KNOWING IF

CURRENT W

AYS OF KNOWING IF

A BUILDIN

G HAS MOULD

A BUILDIN

G HAS MOULD

•Invasive and Destructive

–Destruction of Property

•Mould Sniffing Dogs

•High Resolution Units

–Georgia Tech

•Electronic Nose

–SCENTAUR, Hamilton Thorne Biosciences,

(http://w

ww.hamiltonthorne.com/reseach/environment/scentaur.htm

)

OUR GOAL

OUR GOAL

•To build and test a sensor

that can m

onitor the

growth of mould spores on

a m

embrane accurately

•40 or so sensors will be

built and installed into the

wall cavity of the control

building

MOULD

MOULD

•There are 4 predominant species of mould that are

found indoors, they are:

–Stachybotrys

–Cladosporium

–Penicillium

–Aspergillus

•Our membranes are from the Cladosporium

Shearosperimum

family

•Two types of membranes:

–PVC (Poly Vinyl Carbon)

–Teflon (Ploy Tetra Fluro

Ethylene (PTFE))

Day 0

Day 2

Day 4

Day 6

Day 8

DESIGN REQUIREMENTS

DESIGN REQUIREMENTS

Initial design requirements:

•Photoelectric sensor

•Encasement to be small

(around 1”diameter)

•Able to transm

it data and communicate with

a Data Acquisition System

•Porous encasement –to allow m

ould to

grow

INITIAL EXPERIM

ENTS

INITIAL EXPERIM

ENTS

•Using a Spectrometer to determ

ine the

wavelength that is absorbed by the m

ould.

05

10

15

20

25

30

35

40

410

416

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427

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567

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577

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608

613

618

623

628

Largest reflection shown in Blue Range

450nm

FULL SENSOR

FULL SENSOR

HOUSIN

GHOUSIN

G

Housing units as designed by a 4

thyear group

in Mechanical Engineering, designs done in

Solid W

orks

Battery housing

Micro board

Wireless board

Optical board

Light baffle

Location of

membrane

HOUSIN

GHOUSIN

G

Housing unit as fabricated by the

University Machine Shop

ELECTRONICS

ELECTRONICS

3 Boards –in a tier form

at

1. Optical Board

2. Main Processor Board

3. Data Output Board

With a 4th board for power

Optical

Board

Main Processor

Board

Data Output Board

Main

Power

Inputs/Outputs

Inputs/Outputs

Inputs/Outputs

Inputs/Outputs

Power (6V)

Ground

On/Off Switch to

Boards

Sensor Data

Serial Data

Control of Wireless

Wireless Data

ELECTRONICS

ELECTRONICS

Printed Circuit Boards (PCB)

Designed using Eagle and as fabricated by the

Electronics Shop at UWO

microcontroller

voltage regulator

pins to PC

main power pins

npntransistor

-sw

itch

photodiode

link between

micro &

optical board

LED

Programming pins

DATA ACQUISITIO

N SYSTEM

DATA ACQUISITIO

N SYSTEM

Using

Labviewto

acquire data

through a

serial

connection

RESULTS

RESULTS

This experiment was perform

ed to ensure that the results that are being obtained

from the fabricated PCB are similar to those obtained from the breadboard.

0

0.51

1.52

2.53

3.54

4.55

Da

y 2

Da

y 4

Da

y 6

Da

y 8

Days of Mould Growth

Output Voltage (V)

Fabricated PCB

Breadboard circuit

IMPLEMENTATIO

NIM

PLEMENTATIO

N

•Continue lab testing of the

sensor

•Calibration of the sensor

•Evaluation of current

housing unit

•Fabrication and

implementation of 40

sensors into the control

building