The Design and Fabrication The Design and Fabrication of an Optical - - PowerPoint PPT Presentation

The Design and Fabrication The Design and Fabrication

• f an Optical Sensor for Monitoring
• f an Optical Sensor for Monitoring

the Growth of Mould in Buildings the Growth of Mould in Buildings

Presented By: Anna Sauer

MESc Candidate in Electrical Engineering Supervisors: Drs. Sabarinathan, Savory, & Scott

OUTLINE OUTLINE

• Project Background and Facility
• What is mould?
• Existing Technology for use in the

detection of mould

• Design Requirements
• The Full Sensor
• Components of the sensor
• Results
• Implementation

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

• f different

finishes, such as Aluminum Siding, Brick, etc.

WHAT IS MOULD? WHAT IS MOULD?

• Microscopic organisms known as

fungi, includes: mushrooms, yeast, and mould

• 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

MOTIVATION MOTIVATION

• 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 WAYS OF KNOWING IF CURRENT WAYS OF KNOWING IF A BUILDING HAS MOULD A BUILDING HAS MOULD

• Invasive and Destructive

– Destruction of Property

• Mould Sniffing Dogs
• High Resolution Units

– Georgia Tech

• Electronic Nose

– SCENTAUR, Hamilton Thorne Biosciences,

(http://www.hamiltonthorne.com/reseach/environment/scentaur.htm)

OUR GOAL OUR GOAL

• To build and test a sensor

that can monitor the growth of mould spores on a membrane 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 transmit data and communicate with

a Data Acquisition System

• Porous encasement – to allow mould to

grow

INITIAL EXPERIMENTS INITIAL EXPERIMENTS

• Using a Spectrometer to determine the

wavelength that is absorbed by the mould.

5 10 15 20 25 30 35 40 410 416 421 427 433 438 444 449 455 460 466 471 477 482 487 493 498 503 509 514 519 525 530 535 541 546 551 556 561 567 572 577 582 587 592 598 603 608 613 618 623 628

Largest reflection shown in Blue Range 450nm

FULL SENSOR FULL SENSOR

HOUSING HOUSING

Housing units as designed by a 4th year group in Mechanical Engineering, designs done in Solid Works

Battery housing Micro board Wireless board Optical board Light baffle Location of membrane

HOUSING HOUSING

Housing unit as fabricated by the University Machine Shop

ELECTRONICS ELECTRONICS

3 Boards – in a tier format

• 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 npn transistor

• switch

photodiode link between micro &

• ptical board

LED Programming pins

DATA ACQUISITION SYSTEM DATA ACQUISITION SYSTEM

Using Labview to acquire data through a serial connection

RESULTS RESULTS

This experiment was performed to ensure that the results that are being obtained from the fabricated PCB are similar to those obtained from the breadboard.

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Day 2 Day 4 Day 6 Day 8

Days of Mould Growth Output Voltage (V)

Fabricated PCB Breadboard circuit

IMPLEMENTATION IMPLEMENTATION

• 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