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 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 of 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: Day 0 – Stachybotrys – Cladosporium Day 2 – Penicillium Day 4 – Aspergillus • Our membranes are from the Cladosporium Day 6 Shearosperimum family Day 8 • Two types of membranes: – PVC (Poly Vinyl Carbon) – Teflon (Ploy Tetra Fluro Ethylene (PTFE))
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. 40 35 Largest reflection shown in Blue Range 30 450nm 25 20 15 10 5 0 410 416 421 427 433 438 444 449 455 460 466 471 477 482 487 493 498 503 509 514 519 525 530 535 541 546 551 556 561 567 572 577 582 587 592 598 603 608 613 618 623 628
FULL SENSOR FULL SENSOR
HOUSING HOUSING Housing units as designed by a 4 th year group in Mechanical Engineering, designs done in Solid Works Battery housing Wireless board Micro board Optical board Location of membrane Light baffle
HOUSING HOUSING Housing unit as fabricated by the University Machine Shop
ELECTRONICS ELECTRONICS 3 Boards – in a tier format 1. Optical Board Main Optical 2. Main Processor Board Power Board 3. Data Output Board With a 4th board for power Inputs/Outputs Inputs/Outputs Inputs/Outputs Inputs/Outputs Main Processor Power (6V) Board Ground On/Off Switch to Boards Sensor Data Data Output Board Serial Data Control of Wireless Wireless Data
ELECTRONICS ELECTRONICS Programming pins main power pins LED link between micro & optical board pins to PC npn transistor photodiode - switch microcontroller voltage regulator Printed Circuit Boards (PCB) Designed using Eagle and as fabricated by the Electronics Shop at UWO
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. 5 4.5 Output Voltage (V) 4 3.5 3 2.5 2 1.5 1 0.5 0 Day 2 Day 4 Day 6 Day 8 Days of Mould Growth Breadboard circuit Fabricated PCB
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
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