P13625 – INDOOR AIR QUALITY MONITOR

P R E S E N T E D B Y :

Mechanical Engineers:-Rachelle Radi-Kyle Sleggs

Industrial Engineer:-Jeff Wojtusik

Electrical Engineers:-Alem Bahre Gessesse-Shafquat Rahman

Computer Engineer:-Daniel Bower

Faculty Guide:-Sarah Brownell

AGENDA

• Project Description

• Customer Needs & Specs

• System Architecture

• Development Process

• Concept Selection

• Final Design

• Budget

• Testing

• Outcomes

• Future Improvements

PROJECT DESCRIPTION

• Design an air quality monitor capable of collecting a wider range of relevant environmental factors than the UCB-PATS sensor currently in use

• Develop mounting methods and other techniques for collecting reliable data on site

• Create a system capable of gathering data remotely without external power for several days

UCB- Particulate andTemperature Sensor

Indoor Air Quality Monitor

CUSTOMER NEEDS

ENGINEERING SPECIFICATIONS

SYSTEM ARCHITECTURE

PROJECT TIMELINEPhase 0: Planning•Define Project Goal•Develop Customer Needs•Define Specifications

0

Phase 1: Concept Selection•PUGH Concept Selection•Testing of Selected Sensors

1

Phase 2: Product Design•Validation of design through simulation and breadboard builds

2

Phase 4: Building & Refining•Order parts•Electrical Testing•Final Assembly

4

Phase 5: Testing•Multiple tests•Documentation

5

MSD 2

Phase 3: Final Design•Detailed schematics & drawings•Finalized BOM

3

MSD 1

Current Project Status

Sensors:• CO• PM• Temperature

& Humidity

• Case• Assembly

Method• Hanging

Options

CONCEPT SELECTION

FINAL DESIGN

• 6”x6”x4” Repurposed Conduit Box

• PM, CO, Temp & Humidity Sensors

• Two acrylic plates:

• 1 for Sensor Positioning

• 1 for User Interface

• Basic “core” held together with M4 threaded rod

• Secured into case with 4 L-brackets and screws

LAYOUT

Particulate Matter Sensor

Microcontroller

SDCard

CarbonMonoxideSensor

Temperature& HumiditySensor

5V VoltageRegulator &Heat Sink

UARTModule

3.3V VoltageRegulator

BUDGET• $1000 Budget• $1.82 of the budget remains after

experimentation, building, and testing.

• Able to build 2 monitors

• Compare to the UCB-PATS monitor, the Indoor Air Quality Monitor (IAQM) is effectively $65 less• More functionality (Humidity and

CO)• USB connection cable on IAQM is

more readily available and modern than serial connection cable.

TESTING RESULTS• Test 1 – CO Sensor Calibration (Not Conducted)• Test was not conducted due to lack of safe testing facilities and the potential

health hazards to team members

• Test 2 – Environmental Test (Passed)• While lacking access to the environmental test chamber the team was able

to show expected changes in data over a range of small tests.

• Test 3 – Microcontroller Sensor Communication Test (Passed)• The reading and acknowledgement means that a single reading can be done

in 13 ms (77 readings per second)

• Test 4 – Monitor Endurance Test (Passed)• While the monitor failed a live test due to software issues, the theoretical life

span of the batteries is 9.1 days was calculated using measured power consumption.

• Test 5 – Survey Test (Passed)• There were 21 surveys completed to compile data on the style and usability

of the Indoor Air Quality Monitor. All of the survey points resulted in a average between 7.6 to 8.3 (on a scale of 1 to 10).

MONITOR ENDURANCE TEST

• Monitor experienced a software error during the initial endurance testing.• This test lasted for an initial 68 hours and 4 minutes.

• This forced the team to find alternative testing methods due to a time shortage.

• The batteries used during the initial testing were then removed and measured for remaining voltage.• 7.785V was the remaining potential in the battery packs• This allowed for an average circuit load of 148.53 mA to be calculated

• The remaining useful life of the battery packs could then be calculated• Batteries considered “used” with 5.1 V remaining• With a potential drop of 1.215V• 218.487 Hours OR 9.109 Days

ENVIRONMENTAL TEST

• 15 Minute Test

• 180 Readings

• 1 Reading Every 5 s

ENVIRONMENTAL TESTING W/ CO

• 12 Minutes of Testing

• 140 Readings

• 1 Reading Every 5 s

TESTING RESULTS• Test 6 – Drop Test (not conducted)• The drop test was not completed at this time due to the fragile nature of

the sensors within the monitor

• Test 7 – Computer Interfacing Time Test (Passed)• The monitor transfer a complete set of data in approximately 6.5 seconds

• Test 8 – Mounting Test (Passed)• The team was able to test and document 5 different ways of mounting the

monitor to various surfaces

• Test 9 – Footprint and Height (Passed)• The footprint and height of the monitor are 229.3 cm^2 and 10.95 cm

respectively, which falls into our specifications of 400 cm^2 and 10 cm

• Test 10 – Cost Analysis (Passed)• The total cost of the monitor is $435 (parts and labor)

• Test 11 – Reusability (Passed)• The expected lifetime of the monitor (determined by individual component

life expectancy) is approximately 2.28 years

• UCB-PATS• Cost: $500• Functionality:• Particulate Matter• Temperature

• Serial Computer Interface• Uses one 9V battery

• Indoor Air Quality Monitor• Cost: $435• Functionality:• Particulate Matter• Temperature• Carbon Monoxide• Humidity

• USB Computer Interface• Uses twelve AA batteries

COMPARISON OF MONITORS

FUTURE IMPROVEMENTS• Improve Battery Life of Monitor

• Increase Proven Accuracy of Data Collected

• CO sensor with analog not binary type of output

• Continuous data measurements (time history data)

• Different type of Particulate Matter (PM) sensor (ionization versus optical sensors)

• Design and build testing chamber that would allow accurate control and recording of the temp, humidity, PM, and CO concentrations

• Improve overall lifetime of monitor

• Incorporate SD card for larger quantity of measurements

• Integration of mobile device to accelerate data transfer in the field

• Research into alternative case materials that may not insulate as well as the current case

ACKNOWLEDGEMENTS• Sarah Brownell• Faculty Guide• Help with design process• Help with understanding the challenges that impoverished

nations face

• Dr. James Myers• Assistance with understanding what researchers are looking for

in an Air Quality Monitor• Input on design and functionality

• Mr. Rob Kraynik• Provided technical advice in the construction and manufacturing

of the monitor

• Mr. George Slack• Supporting the design stage of the electrical circuit

• Multidisciplinary Senior Design Department• Provided funding for research and monitor construction

QUESTIONS

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