1. Group 31 Presented by: Yanlin Zhou &Yueqi Ni ECE 445 Senior Design May 1, 2016

2. What is the problem?

3. What is this project about? Air purify system for house use Working with the existing HVAC(Heat, ventilation and air conditioning) system Eliminate Air Pollution Efficiently Energy Saving

4. Why is it cool? Provides a solution to air pollution problems of a house size. Our purify system will not interfere with normal functionality of HVAC. Replaces the traditional supply air grills to a rotatable fan. Automatic speed control through a dust sensor. Energy Saving

5. Design – Block Diagram

6. CPU module What I have learned: Crystal needs to be placed closely to CPU Need multiple resistor / capacitor as protection

7. Temperature Module

8. LM335 Sensor Logic

9. DC Motor Original Design Used CPU pin output to run DC motor directly. Did not work.  Rated Current: 0.25A  Measured Current: 0.043A

10. Modified Design Used NPN Transistor Still had issue  Rated Current: 0.25A  Measured Current: 0.087A DC Motor

11. Final Design Change NPN Transistor to Pull-Down Mode. It Works Well ! DC Motor

12. Dust Sensor Quick Look

13. PM 10 Sensor Tests in Lab Dust Type Air Chalk Vapor Cigarette smoke

14. PM10 Dust Sensor Data Collection

15. PM10 Dust Sensor Facts

16. Passive Infrared Sensor

17. PIR Sensor Challenge – Animals Lens

18. Stepper Motor

19. Stepper Motor Challenges Work with PIR motion sensors to move the fan. Not enough current:  Rated: 0.33A vs. Measured: 0.12A  Solution: DC generator from lab bench or higher battery voltage (e.g. 18V) Different Power Supply system:  9V/18V for Stepper Motor vs. 5V for PIR motion sensors & CPU module  Noise and glitch.  Solution: Same Ground

20. Power Supply Module Theoretical: 9V to 5V (1A) Measured: 9.48V Alkaline DC Vmax: 5.03V Vmin: 4.97V Max Ripple: 32.37mV

21. Conclusion Successfully implement all the individual modules. Generally, the whole system works well.

22.  Improve the false signal processing, eg. Animal detection, radiational wind.  More features to support thermostat, or build our own UI.  Get hands on a real installation for better sensor calibrations.