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Systems Design

Table of Contents 1 Project Background 2 Problem Statement 3 Objectives/Scope 4 Assumptions & Constraints 5 Customer Needs 6 Functional Decomposition 7 Specifications 8 House of Quality 9 Concept Development (generation, improvement, selection) 10 Systems Architecture 11 Risk Assessment 12 Work Breakdown Structure 12.1 Questions 12.2 Action Items 12.3

Project Background

The goal of this project is to redesign and improve the existing air quality monitor currently in use by Dr. James Myers who is using this device to conduct research in developing countries. The device is used to collect quantifiable data on particulate matter from home environments, which include cooking and heating fires. The biomaterials currently being used as fuel for fires in developing countries contains materials ranging from construction debris and excrement to conventional heating materials. The current device being used only measures particulate matter and temperature, and there are issues with the sensors’ durability and cost.

Problem Statement

The primary objective of this project is to improve data collection while simultaneously lowering cost and improving robustness in an effort to make research easier and more cost effective for Dr. Myers and other researchers. In order to facilitate this, a longer battery life and individual gas sensors are being explored for use.

Objectives/Scope

• Improve overall monitor durability
• The ability to monitor individual gas levels,environmental factors, and particulate matter and record them for later analysis
• Devise a method to interface with the device to obtain data

Assumptions & Constraints

• Team must learn how existing gas sensors work, and how they are used to track and record particle levels
• Proposed budget is $500-$650 and must include a greater number of features than the existing air monitor
• Device must function in both high and low humidity environments and provide accurate readings (i.e. Haiti and Kosovo)

Customer Needs

Functional Decomposition

Specifications

Specification Table

House of Quality

House of Quality

Concept Development (generation, improvement, selection)

Sensor Types	Selected Sensors	Cost	Information
CO	MQ-7 Gas Sensor (C9O)	$7.25	Link
PM	PPD42NS	$15.50	Link
Temp&Humid	SHT15	$28.95	Link
RealTime Clock	RV2123C2	$9.00	Link
NO2	e2v	$95.16	Link

Additional Information
Pugh System
Microcontroller family chosen msp430 Link

Systems Architecture

Risk Assessment

Risk Assessment

• Continuously Updated

Work Breakdown Structure

Work Breakdown Structure

• Continuously Updated
• Note use of multiple sheets

Questions

Mechanical:

• Tips on culture and style (What would be considered unobtrusive?)
  
• Suggestions of construction and material types and processes
  
• How to test sensors
  
• Ideas for testing facilities (locations)
  
• Techniques to mount the device (Location in home and How?)
  

Electrical:

• Power Management
  
  • Safe and efficient power distribution between multiple sensors
    
• Feasibility of a rechargeable battery
  
• Sensor output
  
  • Feasibility of analog vs. digital outputs in both hardware and software applications
    
  • Ideas for easier analog conversion
    
• Visible warnings and their effect on the battery life
  
• Feasibility of combining humidity and temperature sensors as opposed to individual sensors (advantages or disadvantages)
  
  

Computing:

• How to test sensors (with regards to hardware and the software interface)
  
• Ideas for testing facilities
  
• Efficient controllers and sensors
  
  • Low power
    
  • Power management
    

Chemical:

• How to test sensors
  
• Potential testing locations (within RIT or elsewhere)
  
• Feasibility of combining humidity and temperature sensors as opposed to individual sensors (advantages or disadvantages)
  
  

Action Items

• Customer Needs-
  • Size of monitor to footprint of monitor
• Specifications-
  • Define Resolution
  • How will we test
• System Architecture-
  • Air Needs to come out of system
  • Signal conditioning for signals coming out
  • Sensors be on all time?
  • Power management
  • Temperature Indicator (switch), turn on/off sensors
  • Calibrate Monitor Block
• Risks-
  • Adequate analysis (simulation, simulate design)
  • What are we going to do? (No adjectives, Mitigation)
  • Mitigation needs to be in Project Plan
  • Gantt Chart (more milestones, more detail on chart)
  • Sub heading detail in Gantt Chart
• Concept Development-
  • Need to compare to Datum (current monitor)
  • Build for lower cost from sp
  • Consider Ion sensor for PM
  • Definition

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