P13625 – Indoor AIR Quality Monitor Presented by: 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 UCB- Particulate and Temperature Sensor 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 and Temperature Sensor Indoor Air Quality Monitor

Customer Needs

Engineering Specifications

System architecture

Project TimeLine Current Project Status Phase 0: Planning Define Project Goal Develop Customer Needs Define Specifications 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 3: Final Design Detailed schematics & drawings Finalized BOM 3 MSD 1 Phase 4: Building & Refining Order parts Electrical Testing Final Assembly 4 Phase 5: Testing Multiple tests Documentation 5 MSD 2 Current Project Status

Concept Selection Sensors: CO PM Temperature & Humidity Case Assembly Method Hanging Options

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 5V Voltage Regulator & 3.3V Voltage Heat Sink Regulator Temperature & Humidity Sensor Particulate Matter Sensor Microcontroller Carbon Monoxide Sensor SD Card UART Module

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

Comparison of Monitors 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

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?