Group 31 Presented by: Yanlin Zhou &Yueqi Ni ECE 445 Senior Design May 1, 2016
What is the problem?
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
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
Design – Block Diagram
CPU module What I have learned: Crystal needs to be placed closely to CPU Need multiple resistor / capacitor as protection
Temperature Module
LM335 Sensor Logic
DC Motor Original Design Used CPU pin output to run DC motor directly. Did not work. Rated Current: 0.25A Measured Current: 0.043A
Modified Design Used NPN Transistor Still had issue Rated Current: 0.25A Measured Current: 0.087A DC Motor
Final Design Change NPN Transistor to Pull-Down Mode. It Works Well ! DC Motor
Dust Sensor Quick Look
PM 10 Sensor Tests in Lab Dust Type Air Chalk Vapor Cigarette smoke
PM10 Dust Sensor Data Collection
PM10 Dust Sensor Facts
Passive Infrared Sensor
PIR Sensor Challenge – Animals Lens
Stepper Motor
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
Power Supply Module Theoretical: 9V to 5V (1A) Measured: 9.48V Alkaline DC Vmax: 5.03V Vmin: 4.97V Max Ripple: 32.37mV
Conclusion Successfully implement all the individual modules. Generally, the whole system works well.
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.