1. Dec03-11 Portable Gas Safety Sensor December 9, 2003
Team Members:
Soell, Sven Qin, Michelle Miao
Ryu, Hwa-Sung
Teoh, Pek-Yee
Advisors:
Dr. Nicola Elia
Dr. Ratnesh Kumar
Clients:
Senior Design

2. Presentation Outline Project Overview Problem Statement
Operating Environment
Intended Uses/Users
Assumptions and Limitations
Expected End Product
Project Activities
Accomplishments
Approaches
Project Definition
Research Activities
Design Activities
Implementation Activities
Testing Activities

3. Presentation Outline (cont)
Resources and Schedules
Personnel Efforts
Other Resources
Financial Requirements
Schedules
Closing Materials
Project Evaluation
Commercialization
Additional Work
Lessons Learned
Risk and Risk Management
Closing Summary

4. Definitions CO Carbon monoxide LCD Liquid crystal display
PCB Printed circuit board
PIC Peripheral integrated controller
PPM Parts per million

5. Problem Statement
The design and implementation of a gas detector for carbon monoxide
A semiconductor sensor indicates the concentration of the gas which will be processed and displayed

6. Operating Environment
The gas detector will mainly be used in residential domains
No extreme environmental conditions
Basement and kitchen

7. Intended Users and Uses
Intended users: - Residents
Intended uses: - To detect and monitor carbon monoxide - Display concentration

8. Assumptions Positioned according to the nature of the target gas
Concentration of target gas must not exceed high levels
Environmental condition should be dry
No other high concentrated gases are present

9. Limitations Costs - $100 Budget No exposure to adverse environment
No excessive vibrations or dropping
Battery life

10. Expected End Product Monitor and display concentration of target gas
Choice of using battery or power outlet
Operating manual

11. Present Accomplishments
Circuit parts and components were ordered
The sensing, data acquisition and display circuit was implemented
Different sensors were implemented/tested
Microcontroller was tested
Programming of the PIC
Power supply
Packaging

12. Approaches Considered
Different kind of gas sensors - Multi-Purpose Sensor  reacts to many types of gases  don’t know the reaction gas
- Specific Gas Sensor (CO)  more accurate  need one sensor for each gas

13. Approaches Considered (cont)
Different programming languages - PIC Basic  Easy to use  Not powerful enough
- C
 Variety of functions available  More complicated

14. Approaches Used Specific sensor for carbon monoxide
C to program the micro-controller

15. Project Definition Detect and monitor the target gas
Display concentration
Keep unit size reasonable
Choices of battery or power outlet

16. Research Activities Different Gas Sensors - Semiconductor : low cost
: long life
: good sensitivity
- Infra red
: detects combustible gases
: not suitable for toxic gases

17. Research Activities (cont)
Programming Languages
- C - PIC Basic

18. Design Activities
Sensor circuit

19. Design Activities (cont)
Overall Circuit

20. Implementation Activities
Use of different gas sensors
 Multipurpose sensor  Specific sensor for CO
Use of different coding languages  Pic Basic  C

21. Testing Activities
Hardware Test - Sensor - Sensing, data acquisition, and display circuit - Power supplies
Software Test - Programming of PIC - Look-Up-Table - Display

22. Testing Activities (cont)
End Product Test - Functionality - Comparison to a commercial product - Battery life

23. Test Results

24. Test Results (cont) Accuracy within 20%
More accurate in higher ppm range
Battery life about 1 hour
Sensor takes long time to settle

25. Other Activities
Packaging
Writing the user manual

26. Personnel Efforts

27. Other Resources

28. Financial Requirements

29. Schedules

30. Schedules (cont)
Cause of Delays - Implementation of different sensor - Not all tools available (compiler)

31. Project Evaluation Order parts fully met
Circuit implementation fully met
Programming partially met
Calibration fully met
Packaging fully met
Testing partially met

32. Commercialization Production Cost $50
- parts only, not including labor
Selling Price $70

33. Additional Work Include more gas sensors
Increase accuracy by using more expensive sensors
Build a monitoring system which interacts with environment

34. Lessons Learned The Devil is in the Detail Time Management
Communication among team members
Organization
Things often do not work the way you want them

35. Risk and Risk Management
Equipment Damage
- Keep back up, order more quantities
Late Arrival of Parts and Equipment
- Order in Advance
- Select Alternatives

36. Closing Summary Portable Gas Safety Sensor accuracy and reliability
portable and easy to use
economical

37. Questions